FAQ
User Tutorial
For Planning Permit Applicants
Blue Factor has been designed with online help and guidance to work progressively through an assessment, and experiment with potential improvements along the way.
Blue Factor is the successor to STORM and replaces it as the recommended tool under relevant planning policy and requirements for assessing whether development meets stormwater management requirements.
Blue Factor can assess single houses, townhouse developments, apartment buildings, smaller commercial and other non-residential or mixed use developments.
For larger and more complex developments, it is recommended to use MUSIC rather than Blue Factor. Specifically, it is recommended that any developments containing a public road or car parking should preferably use MUSIC. However, at a minimum, such developments should seek compliance with all parameters in Blue Factor rather than just relying solely on the Blue Factor Score.
Blue Factor can also be used to support an assessment through BESS which is the recommended tool under the Sustainable Design Assessment in the Planning Process (SDAPP) framework.
Blue Factor becomes more complex with the complexity of the development:
- For single houses or renovations, no prior experience is required to use Blue Factor although we recommend you start with the User tutorial and read through the Tool notes. However, you will always benefit from using professionals (architects or building designers) with sustainability credentials.
- For multi-unit, non-residential and mixed use developments, a sustainability professional such as an ecologically sustainable development (ESD) or water sensitive urban design (WSUD) consultant should always be engaged to prepare the assessment and to advise on the project from the concept design phase.
To begin your assessment you will need to login to the tool. If this is your first time using Blue Factor, you will need to register an account.
Once logged in, you will need the following information about your project:
- Town planning drawings
- Drainage layout plan
- Knowledge of water sensitive urban design assets such as rainwater tanks and raingardens
- An understanding of the physical layout of the site, where water drains and potential locations for water sensitive urban design assets for treatment or reuse
For technical support or to provide feedback or suggestions, use the Contact form.
For Councils
Blue Factor has been developed with support from DEECA. The tool is free for planning permit applicants, but can only be used within the state of Victoria.
For authorities outside Victoria, please contact us if you wish to discuss potential to extend the service area.
Rainfall falls on the ground and is absorbed into the soil. Most of it (about 70-80%) goes back into the atmosphere through evaporation and transpiration (plants using water). A small portion of it infiltrates deep into groundwater and a smaller portion flows into our creeks and rivers. This creates flow patterns in our waterways where most of the flows enter through the soil and groundwater and are called baseflows. Surface flows mostly occur during wet periods in winter or in larger storms.
Our creeks, rivers and bays have all sorts of amazing creatures in them like bugs, fish, birds and platypus. These are adapted to the particular flow patterns where they live. These can vary from a dry creek bed that has deep pools of water and only flows for a few months to large rivers with steady baseflows year round.
We all understand removing water from our rivers using dams for use in cities or agriculture can change the flow patterns and impact on the many creatures that live within them.
What is less well understood is that towns and cities have a much greater negative impact on habitat and waterway creatures by increasing the flows into them.
In our towns and cities, we remove the vegetation and cover the land with buildings, roads and other surfaces that don't absorb water.
This means less water can be absorbed into the soil, returned to the atmosphere through evaporation and plant transpiration and infiltrated into the ground.
Where does all the extra water go? Well, if we didn't do anything, we would have floods so we build efficient drainage pipes and channels to get the water to the waterways and away as quickly as possible.
Unfortunately in our towns and cities, the direct surface stormwater flows into our waterways are as much as 3 to 5 times greater than they would be naturally. This massive increase in flow volumes has a big impact on our waterways and all the creatures living within them.
The frequency of flows also increases, from just occassional storms to every time it rains. These changes have impacts like increased erosion and removal of habitat. It can also wash away eggs before they have a chance to hatch and some of our native species literally cannot swim upstream against the higher flow rates.
Next time there's even a little rain, walk by one of your local creeks and see how the water level has risen.
Not only do towns and cities produce much more stormwater flows than would occur naturally, they also discharge a cocktail of stormwater pollutants that can be harmful to the creatures living in our creeks and waterways. These can include:
- Sediment
- Nutrients like nitrogen and phosphorus
- Heavy metals
- Pesticides and herbicides
- Pathogens
Like increased stormwater flows, stormwater pollutants put stress on creatures living in waterways. Frogs are actually highly sensitive because they can absorb pollutants directly through their skin.
- Sediment- Can smother habitat and remove in-stream variety. Sediment also carries a range of other pollutants like heavy metals and can smother seagrass. These present a threat to the Ramsar listed seagrass meadows of Western Port.
- Nutrients - Nitrogen and phosphorus loads contribute to algal blooms. Nitrogen is most important for salt water and phosphorus for fresh water. Reducing nitrogen loads to Port Phillip Bay is a key focus for the greater Melbourne area. Most nitrogen is derived from the atmosphere and the problem is the increase in volume increasing loads. Agricultural fertilisers are another important source.
- Heavy metals- Can be toxic to plants and animals in waterways. Heavy metals mostly come from roads and industry.
- Pesticides and herbicides - Can affect plants and animals in waterways
- Pathogens - Can make humans or animals sick and need to be removed before stormwater is reused for purposes like irrigation
What are we doing about it?
As a country, we have made huge progress on reducing industrial discharges and raw wastewater going into waterways over the past 50 years.
However, in the last few decades, cities like Melbourne have grown substantially. We have also changed the way we build, from a house with a large backyard to either densely packed townhouses or large houses on smaller lots with very little backyards. This means even more impervious surfaces and less space for water to soak into the ground. As a result, there is even more stormwater to manage and greater impacts on our creeks, rivers and bays.
Over the past 20 years, planning requirements mean most big new developments on our city fringes have stormwater treatments like wetlands. These help to slow the increase in pollutant loads flowing to our waterways.
However, addressing the legacy of existing urban areas is a big challenge.
Water authorities and Councils also retrofit stormwater treatments like wetlands and raingardens in existing towns and cities but there is simply not enough space available in the right places.
Planning requirements are in place so that all new developments within existing towns and cities reduce their stormwater pollutant loads. In this way, they are doing their part by managing stormwater at the source where it is generated.
The 3 things that can be done at the development stage are:
- Reduce the quantity of water the house or business will consume
- Reduce the quantity of stormwater that flows into drains and downstream waterways
- Improve the quality of stormwater discharged
Water sensitive urban design or WSUD is an approach to planning and urban design that recognises the important role of water and takes it into account within the planning process. When doing WSUD we will:
Protect waterways and waterbodies - Stormwater contains pollutants like sediment that smothers habitat, nutrients that can lead to algal growth and heavy metals, hydrocarbons and other toxins that can kill fish and other aquatic life
Make way for the river - Make sure waterways have adequate floodplains to contain flood flows and that water is stored and managed within the catchment where there is opportunity
Maintain a hydrologic balance - Urban development removes plants from the landscape and covers soil with buildings and roads, preventing natural evaporation and transpiration of water and infiltration to groundwater. This greatly increases rapid and damaging surface runoff into waterways, causing downstream flooding and eroding stream banks while reducing natural baseflows. WSUD increases evapotranspiration and infiltration to reduce these effects
Reuse stormwater - Every year we discharge enough excess stormwater into our waterways to meet our cities water needs. Instead of taking this water from other waterways or wasting energy with desalination and pumping we can treat and use the water flowing down our streets and drains.
Water sensitive urban design (WSUD) has been mandatory for all new residential subdivisions in Victoria under Clause 56.07 of the Victorian Planning Provisions since 2006.
The requirement to undertake a WSUD approach and to meet standard requirements was extended to most forms of subdivision and development through Amendment VC154 to update the Victorian Planning Provisions.
If you are sub-dividing or developing it is likely you will need to meet these requirements.
Additional planning provisions were introduced in 2018, including Clause 53.18 – Stormwater management in urban development. These extened the existing requirements to:
All commercial and industrial subdivisions and developments
All public use developments
All residential multi-dwelling developments
Further details can be found here: Amendment VC154
Some Councils also have requirements for other types of developments.
Do stormwater requirements apply for my development?
If you are not sure what requirements apply for your development, then use the Online Navigator Tool to find out here:
https://clearwatervic.com.au/resource-library/toolkits/stormwater-planning/
At a minimum, most development types need to meet the current best practice performance objectives for stormwater in the Urban Stormwater Management Guidance (EPA, 2021) or, for some objectives, have achieved ‘as much as is reasonably practicable’. See here for more details: https://www.epa.vic.gov.au/urban-stormwater-management-guidance
Some forms, such as subdivision of existing dwellings and/or car parks may be exempt.
In all cases, you should also consider what obligations you may have under the General Environmental Duty (GED).
There are a range of treatments available in Blue Factor.
At present, these are limited to:
More treatment types will be progressively rolled out.
Learn more about other stormwater treatments here:
There is no one right answer for which treatment to use. It will depend on the opportunities and constraints presented by the site.
If most of the impervious areas are roofs, then a rainwater tank will usually be the simplest response. Rainwater tanks are also effective in combination with another treatment for any ground surface areas. Rainwater tanks are used on more than 90% of sites and when optimised will provide the greatest benefit for the home-owner.
For treating ground surfaces, raingardens and permeable paving are the most common approaches.
Raingardens are a space efficient and flexible treatment system that be used to treat runoff from any surface. However they are more complex and require greater ongoing maintenance than buffers and swales.
Permeable pavements can reduce the impervious area requiring treatment by converting a driveway into a porous surface that allows water to infiltrate into the soil below it. However they are a relatively higher cost response.
Buffers and swales are cost effective ways to treat smaller impervious areas including driveways and small roof areas.
An infiltration trench should generally only receive stormwater with low concentrations of sediment, that is only rainwater from roofs or stormwater that has passed through another treatment to remove sediment. Infiltration trenches receiving flows from roof areas may be modelled in Blue Factor. Infiltration trenches are most commonly used in coastal areas.
These assets are most effective in areas with sandy soils. They require greater levels of expertise to implement as they require careful consideration of soil conditions, flow pathways and potential contamination risks.
Generally, in optimising the tank, a minimum rainwater tank volume of at least 2 kL (2,000 Litres) for every 100m2 of total roof area is recommended.
Water should be collected from at least 60% of the new roof area including any attached garage. Increasing the catchment will increase the amount of water flowing to the tank. This is especially important in drier areas.
The tank should preferably be connected to all toilets, cold water tap in the laundry and garden taps. Connecting to more uses is most important in wetter areas to absorb the higher flow volumes.
Optimising the tank reduces the need for additional assets. Usually, an optimised rainwater tank only needs to be installed with one extra asset type for treatment for the next largest surface area. An optimised rainwater tank also reduces demand on the reticulated water supply.
All Victorians have responsibilities under the General Environmental Duty (GED). You need to understand the risks your business activities may pose to human health and the environment and how to address them as far as reasonably practicable.
Further information about these obligations can be found here:
https://www.epa.vic.gov.au/general-environmental-duty
Information on the Environment Reference Standards is set out here:
https://www.epa.vic.gov.au/environment-reference-standard
The ‘State of knowledge’ is all the information you should reasonably know about managing your business’s risks.
Guidance on the state of knowledge specific to stormwater is set out in the urban stormwater management guidance:
The key take-away from this guidance is that stormwater pollution needs to managed. Urban development results in significant increases in stormwater 'excess' flow volumes being generated as well as higher concentrations of pollutants, relative to natural conditions.
Firstly, stormwater should be treated as established through long-standing practices to manage and address stormwater pollution risks in accordance with existing planning requirements.
Secondly, stormwater excess volumes and changes to the natural hydrology should be minimised to protect waterways. This means seeking to retain water on-site through evapotranspiration (evaporation and plant transpiration) and harvesting as well as infiltration to soils to recharge groundwater and preserve natural baseflows.
A water sensitive urban design (WSUD) approach seeking to eliminate or minimise risks through reduced impervious surfaces and to further mitigate risks through stormwater treatment and harvesting is recommended.
Melbourne Water have developed a Healthy Waterways Strategy.
The strategy identifies 9 key community values associated with waterways:
- fish
- platypus
- frogs
- birds
- macroinvertebrates
- vegetation
- amenity
- community connection – with each other and nature
- recreation
Learn more here: https://www.melbournewater.com.au/water-and-environment/water-management/rivers-and-creeks/river-health-and-monitoring
Learn more about how Melbourne Water is researching ways to save platypus in our creeks and rivers within Melbourne using smart tanks: https://pursuit.unimelb.edu.au/articles/saving-melbourne-s-platypus-with-smart-water-storage
What are we doing to make our waterways healthy?
As a country, we have made huge progress on reducing industrial discharges and raw wastewater going into waterways over the past 50 years.
However, in the last few decades, cities like Melbourne have grown substantially. We have also changed the way we build, from a house with a large backyard to either densely packed townhouses or large houses on smaller lots with very little backyards. This means even more impervious surfaces and less space for water to soak into the ground. As a result, there is even more stormwater to manage and greater impacts on our creeks, rivers and bays.
Over the past 20 years, planning requirements mean most big new developments on our city fringes have stormwater treatments like wetlands. These help slow down the rate at which we are increasing pollutant loads, but there is still a net impact.
However, addressing the legacy of existing urban areas is a big challenge.
Water authorities and Councils have retrofitted stormwater treatments like wetlands and raingardens in existing urban areas but there is simply not enough public land available and this land has many competing needs.
Planning requirements require that new homes and businesses within existing towns and cities do their part by managing stormwater at the source where it is generated. This further slows the rate at which we increase stormwater flows and pollutant loads.
It will be easier to prepare a Blue Factor model if you have a site layout plan
The Townhouse and Low rise housing code provides some guidance on preparing a site layout plan.
1: Provide a site layout plan showing the site boundary, dimensions, and total site area
2: Show all building roofs and covered areas, pervious (unsealed) surface areas and impervious (sealed) surface areas with dimensions and areas. These details must be consistent with the plans and other documents lodged with the planning application.
3: Show the legal point of discharge.
4: Specify the area draining to each downpipe, treatment and legal point of discharge – including both impervious and pervious areas.
The following may be drawn or updated based on iterative design using Blue Factor:
5: Show the location, type and surface area (sqm) of the proposed WSUD treatment assets on a plan, including how each internal catchment area to be treated will be connected to a WSUD element (e.g. roof to rainwater tank, driveway to raingarden).
Show how piped connections will be made within the site and to the legal point of discharge.
Clearly annotate any impervious areas not being treated by a WSUD asset.
Some Councils offer a stormwater offset. Where this is available there are two ways to achieve compliance:
A) Achieve a 100% stormwater treatment compliance on-site.
This is the most common pathway.
B) Achieve a minimum specified percentage stormwater treatment compliance on-site then make a financial contribution to Council through the WSUD Developer Voluntary Contribution Scheme.
This is a voluntary option available to planning applicants and prerequisites apply.
The contribution is calculated based on the stormwater offset rate and the equivalent area of developed untreated impervious area.
WSUD voluntary contribution = Total impervious area of the site X Percentage variance (100 per cent - STORM Rating per cent) X WSUD voluntary contribution rate (e.g. $55)
Further information can be found on the respective Councils website:
Moonee Valley
https://mvcc.vic.gov.au/work/my-development/sustainable-development/
Kingston
Mornington Peninsula
https://www.mornpen.vic.gov.au/Environment/Water/Stormwater-Quality-in-lieu-Contribution-Scheme
Building demands are calculated based on the number of occupants.
For residential, occupants are residents.
For non-residential, occupants are employees.
Average demands or water use
The typical per person water use based on water retailer end use data is used as a basis.
The number of occupants is multiplied by the water demand per person for each given use supplied
Water use calculated based on fittings and fixtures
The typical per person water use is estimated based on an assumed flow rate and number of uses per day.
The number of occupants is multiplied by the water demand per person for each water use.
Toilets
The total toilet use demand is calculated based on the number of occupants and water use per person per day.
The number of toilets connected to each source may be defined. The total use is then apportioned to each source based on the proportion of toilets connected to it. This does not change the total toilet use estimated. This is intended to allow for the situation where a rainwater tank is connected to one or two toilets in a house (e.g. the downstairs toilets) while mains water is used for others.
It is recommended to connect all toilets within a building to the rainwater tank where possible. This will increase benefits in terms of potable water savings to the householder as well as reducing stormwater excess flows to the environment.
Laundry
Laundry use per person per day is slightly greater than toilet water use.
This means that connecting laundry use to a rainwater tank significantly increases the demands on it.
Connecting laundry uses will increase benefits in terms of potable water savings to the householder as well as reducing stormwater excess flows to the environment.
Irrigation
Irrigation demands vary seasonally and can be less certain than constant internal uses.
However, they are relatively easy to connect and increase benefits in terms of potable water savings to the householder as well as reducing stormwater excess flows to the environment.
Providing water for irrigation also helps to keep gardens and lawns green in summer which helps improve landscape amenity, supports healthy plants and trees and can contribute to urban cooling.
Overall
The more demands or uses that are connected to a rainwater tank, the more water will be used, resulting in greater performance in terms of stormwater treatment and flow volume reductions.
Overall outcomes may be limited by the flows coming from the roof, the tank size or the demands. If the demands are already large relative to the flows from the roof or the storage is too small, increasing demands will have limited effect. This can be seen by a small increase in performance when the demands are increased.
The uses connected to a rainwater tank should preferably be maximised, subject to being realistic and reasonable for the context to get the best benefits and value from a rainwater tank.
Blue Factor is intended for small-scale redevelopment sites.
It is recommended that Blue Factor is only used for development sites up to 1 ha (10,000 m2).
Larger sites may have other treatment assets such as wetlands or sediment ponds, more complex treatment trains and additional considerations for hydrology.
MUSIC or a suitable equivalent may be used for large development sites.
Blue Factor was designed to support small-scale residential and simple commercial developments with a simple and accessible tool.
Currently the following development types are supported with the in-built calculator for demands:
Residential
- Detached house
- Townhouse
- Apartment
Non-residential
- BCA Class 5 - Commercial / Office
- BCA Class 6 - Retail / Food
- Mixed use
These types are supported because:
- Total suspended solids (TSS) loads are usually very low from these development types post-construction and reliance upon the STORM score method is therefore a reasonable and practical approach.
- Data is available to support estimation of demands
Other development types can also be assessed. However, the simplified assessment used for the low-risk types above may not be suitable and a broader assessment of pollutant loads is needed. Consideration of progress towards flow volume objectives is also recommended.
See 'Using the score' and the EPA stormwater management guidance (EPA, 2021) for more information. https://www.epa.vic.gov.au/sites/default/files/2025-09/Urban-stormwater-management-guidance.pdf
Like STORM, Blue Factor is intended as a simple and accessible tool.
The STORM or Blue Factor score generated may be used to assess small-scale low-risk developments including the following:
of less than 1 hectare that do not include public roads.
Currently the following development types are supported with the built-in demand calculator:
1. Small-scale residential developments
- Detached house
- Townhouse
- Apartment
2. Simple and small-scale commercial developments including:
- BCA Class 5 - Commercial / Office
- BCA Class 6 - Retail / Food
- Mixed use
In terms of General Environmental Duty obligations, the designer should generally consider:
- Stormwater flow and pollutant risks created by the development (Hazard)
- Values, sensitivity and potential impacts to receiving waterways and water bodies (Potential impacts)
- Soil conditions and properties
- Extent to which hazards (impervious surfaces, generation of pollutants) will increase and extent to which these have been eliminated, minimised or substituted
- Controls in place to reduce risk (e.g. WSUD)
The STORM or Blue Factor score is intended to provide a simplified deemed to comply approach for developments where the hazard presented by litter and sediment pollutant loads is relatively low.
It is based on assessing the extent to which the total nitrogen pollutant load reduction is achieved. This practice has been in place for over 20 years through use of the STORM tool.
This is consistent with the risk-based approach adopted in the Urban stormwater management guidance to identify hazards and assess potential impacts.
The use of the score in isolation is limited to the above types of developments that have the following characteristics
- Low levels of litter and sediment generation
- No public road areas (which may generate significant sediment)
- Car parking is limited in area and primarily used by occupants or visitors with low traffic levels
- Total of roof and paved surfaces comprise at least 50% roof areas
In particular, the user should consider:
- The values and sensitivity of the receiving waterway
- The risks and values of stormwater excess flow volumes and and whether or not or the extent to which these objectives are met
- The risks of litter and sediment generation, values of receiving waterways and whether or not or the extent to which these objectives are met
- Whether an offset will be paid to meet any shortfall in its objective obligations (recognising offsets are specific to meeting the total nitrogen objective)
While not yet mandated for planning, it is recommended that significant progress towards meeting stormwater flow volume objectives should be demonstrated for most or all developments discharging to waterways (i.e. not directly to a bay or ocean).
For other development types or developments where the above characteristics are not met, it is generally recommended that all stormwater pollutant load objectives are met.
Please refer to the Urban stormwater management guidance for more information: https://www.epa.vic.gov.au/sites/default/files/2025-09/Urban-stormwater-management-guidance.pdf
I want to discuss my project with Council, how can I share it with them?
Once a project is published, it can be made available for viewing by Council officers.
The consultant or user can contact the council directly and provide them with the unique project id. Some staff at the Council will then be able to view the project. This allows the user and Council to discuss the project directly and quickly reach a satisfactory and acceptable outcome.
The applicant for the Planning Permit then attaches the report/score card to the planning permit application. This can help speed up the planning process by reducing the need for iterative written referrals and responses.
When a planning permit is submitted to Council it is recommended to include the following:
- A Blue Factor report
- A WSUD plan showing all catchments and treatments and their area (Refer site layout plan)
- Written documentation and justification for any key assumptions
How should existing STORM projects be treated?
Existing STORM projects should, where possible be transferred to BlueFactor. In some cases it may be appropriate to use another acceptable compliance tool such as MUSIC.
If transferring a particular project is too difficult then please contact: [email protected]
It is recognised that construction and buildings works generate a significant proportion of the sediment generated over the life cycle of urban areas.
During greenfield development, soils are exposed during bulk earthworks and subdivision construction and are at significant risk of significant erosion. This continues through the building and landscaping phase (Russell, 2017).
Research suggests that construction phase sediment loads can be 5-50 times as much as those post-establishment.
Furthermore, it is estimated that in areas with suburban infill, overall catchment sediment loads may be as much as 25% higher than those without significant infill activity. Building sites can also be significant sources of litter or gross pollutants.
Preliminary inspections suggest that as many as 80-90% of typical infill building sites do not comply with even the three most basic litter, sediment and erosion control measures such as:
- Contained litter storage
- Stabilisation of trafficked exposed soil surfaces
- Bunding of stockpiles
This means that there is ready opportunity for significant improvement in overall catchment outcomes. This can be achieved through use of simple and cost-efficient sediment and erosion controls for a relatively short period of time of up to two years during infill construction. This is therefore a highly effective and cost efficient means of reducing sediment loads. See 'Construction phase sediment and erosion control' for further information.
Planning and building requirements should require that sediment and erosion controls are in place throughout the construction phase.
These should be enforced through regular inspections of building sites by Council.
Resources
A range of potential resources are available to support management of risks from erosion and sediment
Keeping our stormwater clean: A builders guide: https://www.clearwatervic.com.au/resource-library/guidelines-and-strategy/keeping-our-stormwater-clean-a-builders-guide.php
EPA guidance on managing risks from erosion and sediment
Erosion and sediment control guide (North-east Victoria Councils): Erosion and sediment control guide for building sites
International erosion control association
Many Councils have specific guidance on water sensitive urban design.
Search for 'water sensitive urban design', 'WSUD' or integrated water management on their website.
For example, information for Brimbank can be found at the following:
Brimbank City Council
Guidance for drafting ESD reports for WSUD: Water Sensitive Urban Design Report (WSUD)
Guidance on water sensitive urban design: Brimbank ESD guidance - Water sensitive urban design
Guidance on water efficiency and reducting potable water use: Integrated Water Management
Moonee Valley City Council
https://mvcc.vic.gov.au/work/my-development/sustainable-development/#water-sensitive-urban-design
This document sets out the terms and conditions relating to use of Blue Factor and the terms of use under which you are provided access as a Registered User to Blue Factor (the terms).
IMPORTANT PLEASE READ THE TERMS AND CONDITIONS OF THIS LICENSE AGREEMENT CAREFULLY BEFORE CONTINUING TO USE THIS WEBSITE.
These terms and conditions are a legal agreement between you (either an individual or a single entity) and Microburst Software for the Blue Factor website including all associated software components, media, printed materials, and "online" or electronic documentation ("Blue Factor").
By viewing or using Blue Factor, you agree that you and the organisation you are representing will be bound by the terms of these terms and conditions. These terms and conditions represent the entire license agreement concerning Blue Factor between you and Microburst Software, (referred to as "licenser"), and it supersedes any prior proposal, representation, or understanding between the parties. If you do not agree to the terms of this EULA, you must discontinue use of Blue Factor now.
Blue Factor is protected by copyright laws and international copyright treaties, as well as other intellectual property laws and treaties. Blue Factor is licensed, not sold.
If you have any questions about these terms and conditions or wish to correct your personal information, please contact us.
- Definitions
- Blue Factor refers to the Blue Factor website including all data, information, software, calculations, databases and other materials contained within it.
- Microburst Software refers to Microburst Software Pty Ltd
- DEECA refers to the Department of Energy, Environment and Climate Action, Victoria
- General conditions
Agreement
In accessing and using the Blue Factor website, you agree that you have read and understood all of the relevant terms including but not limited to the Terms and conditions, General Conditions, Disclaimer, Copyright and Privacy Statement.
Grant of license
Blue Factor is licensed as follows:
Use of Software
Microburst Software grants you a non-exclusive, revocable, non-sublicensable, limited license to access and use Blue Factor.
Internet charges
You may access Blue Factor on your computer through the use of an internet browser (such as Edge, Internet Explorer or Chrome).
You are wholly responsible for any internet connection fees that you incur.
Area of use
Blue Factor is strictly intended for use on projects only within the service area or area of jurisdiction of specified ‘Authorities’ that have a license agreement with Microburst Software. These may be a government department, water authority, catchment management authority or municipal council.
The user agrees that, to the best of their knowledge, Blue Factor will only be used for projects located within a designated service area. The application of Blue Factor for projects outside the relevant service area may lead to erroneous results and the user is wholly responsible for any such use and its consequences. Where such use is identified, Microburst Software reserve the right to suspend or terminate the user account of any or all users belonging to the corresponding company or organisation.
Where an ‘Authority’ license agreement exists, sub-authorities within the service area may also elect to use Blue Factor for the purpose of assessing Development Application compliance with stormwater requirements. Such use is subject to any additional terms and conditions within a relevant Authority license agreement and those contained herein.
The specified authority is the Department of Energy, Environment and Climate Action (DEECA) of the State of Victoria, or as revised.
The designated service area for Blue Factor is: The State of Victoria
New or revised Terms and Conditions
Microburst Software reserve the right to update these terms and conditions at any time without notice.
However, where practical, you will be notified of any significant changes and given the opportunity to accept the new terms and conditions. When this occurs, your right to access and use the Tool or the Service under the existing terms will terminate immediately upon notice of the new Terms and Conditions of Use for Registered Users (the terms). You will be given an opportunity to review and accept the new terms. If you accept, and if the log-on identity registered to you is accepted, you will be able to continue using the Tool and the Service subject to the conditions of the new terms. If you decline to accept the new terms, or if you cannot comply with the conditions of the new terms for any reason, you will no longer be permitted to access the Tool or Service.
Governing law
Your access to and use of Blue Factor is governed by the law of the State of Victoria and the Commonwealth of Australia, and you agree to submit to the non-exclusive jurisdiction of the courts in those locations.
Service availability
It is impossible for Microburst Software and DEECA to ensure that the services are provided to you at all times or at any specific times or will be able to operate at all times error-free. After hours provision of services are influenced by availability of related computer systems. Microburst Software and DEECA make no warranties in regard to the availability of services but all reasonable efforts will be made to provide the best possible service to you.
- Copyright
All title, including but not limited to copyrights, in and to Blue Factor and any copies thereof are owned by Microburst Software 2025. All rights reserved.
All title and intellectual property rights in and to the content which may be accessed through use of the Blue Factor is the property of Microburst Software or the respective content owner and may be protected by applicable copyright or other intellectual property laws and treaties.
This agreement grants you no rights to use such content other than in accordance with terms of this agreement. All rights not expressly granted are reserved by Microburst Software.
All content on this website viewable after logging in may not be copied, reproduced or used without consent. Please contact us to seek permission to reproduce, alter, store or transmit copyrighted material from this website for any purpose.
Permission is hereby granted to registered users to use a Blue Factor report that can be generated through this website, provided that:
Any reports are unaltered (other than by completing information entered in the input forms). When providing the reports to third parties it is the user's responsibility to ensure that they are up to date at all times
Use of website materials as training data or within any other system or service
The use of any material on this website as training data for a model, artificial intelligence (AI) or any other system is explicitly prohibited, except for the purposes of web search and indexation.
Notwithstanding the above limitations, should any part of this website, associated data or databases be used within any training data for a model, system or service in any form without written permission, the owner of that model, system or service agrees to immediately and without delay assign the greater of $10,000 or ownership of 1% of all shares of the owning parent company to Microburst Software without reservation and to undertake all actions necessary to effect the transfer of funds or shares.
In using material from the website, the owner of the model or AI system asserts that it has granted permission by an authorised person of the owning parent company for this ownership transfer to be made. Interest shall be payable on any delay in effecting this transfer exceeding 90 days from the date of extraction of information and/or data at 12% per annum compounded daily.
It is further agreed that any such model, system or service will be immediately withdrawn from use upon receiving a written request from Microburst Software, regardless of any fees as outlined above. Continued use constitutes a breach of this license agreement and the laws of the State of Victoria and the Commonwealth of Australia.
Maintenance of Copyright Notices
You must not remove, alter, deface or destroy any copyright notices or other proprietary marking of Microburst Software on any and all copies of Blue Factor or any associated materials or reports.
- Terms of use
Only registered users can access and use the Blue Factor website. Registered users of this site agree to be bound by these Terms of Use and are provided access to Blue Factor on this basis only.
Before you can use Blue Factor, you must read, understand and agree to these Terms and Conditions (the terms). In accessing and using the Blue Factor website, you agree that you have read and understood the terms and other relevant documents including but not limited to General Conditions, Definitions, Copyright, Code of Conduct, Disclaimer and the Privacy Policy.
User eligibility
You may register to use Blue Factor for the purposes of accessing or using the website and to prepare a Blue Factor report only if you are over 18 years old, a corporation, Limited Liability Company, partnership or other legal or business entity registered to trade in an Australian jurisdiction.
Becoming a Registered User
You must register as a user (“Authorised user”) to access and use the Blue Factor website and to prepare a Blue Factor report. When creating or updating a Registered User log-on, you are required to provide certain personal information such as your name, phone number, email address, company and default municipality. You agree that you will supply accurate and complete information when requested, and that you will update that information promptly after it changes. Refer to our Privacy Policy and/or contact us directly if you have any concerns about providing this information.
Username and password
In creating an Account, you will be required to select a unique username and password (collectively, “Login Credentials”), which you will use each time you access the Blue Factor website.
You agree that it is your responsibility to keep these secure. You agree not to share the Login Credentials with anyone other than as expressly authorised by these Terms of Use. You are responsible for maintaining the confidentiality of the Login Credentials, and are responsible for all uses of the log-in identity, including payments, whether or not authorised by you.
In the event you become aware of or reasonably suspect any breach of security, including without limitation any loss, theft, or unauthorised disclosure of the Login Credentials, you agree to immediately log-in and change it and to also advise us by using the Contact Us link on the home page.
To respond to enquiries, Microburst Software, DEECA, Water Authority or Council staff may request that you disclose your username. Such disclosure is not a breach of these terms.
User and Project Details
Information entered into the Blue Factor website to prepare a Blue Factor report may be accessed by DEECA and Council officers for the purposes of responding to help requests, for quality control, auditing and compliance checks as well as assessing a Development Application for stormwater compliance.
Ownership of Blue Factor reports
Ownership, interest, copyright or other intellectual property value contained in project files is limited to any interest or rights the user, or any third party, may have in the design of the project, and does not extend to the added value, if any, that the details have as a Blue Factor project file, as a means to calculate ‘STORM’ or ‘Blue Factor’ scores or compliance with planning requirements and objectives or to generate a Blue Factor report.
You agree that ownership of the Blue Factor project files created by you remains with Microburst Software and any right to access, modify, add or amend projects is granted by Microburst Software at its discretion and in accordance with any limitations contained within these Terms of Use.
Discontinuation or modification of the Blue Factor Tool
Microburst Software and/or DEECA may change, modify, suspend, or discontinue any aspect of the Blue Factor website at any time. You have no interest, monetary or otherwise, in any feature or content contained in the website or associated with your project files. Microburst Software, DEECA and Council may also revise other policies, including without limitation the Best Practice objectives and STORM score assessment methods, at any time.
Notwithstanding that no notice is required, Microburst Software and DEECA will use reasonable endeavours to advise you of changes to the Blue Factor website, but will not be held liable for failure to notify.
Improper use of the Blue Factor website ('the site')
You agree that you will not, under any circumstances:
- Seek to log in to an account that you have not created unless you are an authorised Microburst Software or DEECA administrator. If you are found to have logged into another individual or organisations accounts without written evidence permission, you and your organisation may be permanently excluded from using Blue Factor.
- modify or cause to be modified any Blue Factor reports in any way not expressly authorised by Microburst Software or DEECA, attempt to gain unauthorised access to project files registered to other users, or the computer systems or networks connected to the site.
- Instigate, encourage, sponsor, institute, assist, or become involved in any type of attack, including without limitation denial of service attacks, use automation software, hacks, or any other unauthorised third-party software designed to modify the website, intercept, "mine", or otherwise collect information from or through the website or otherwise attempt to disrupt the site or any other person's use of the site;
- host, provide or develop matchmaking services for the site, or intercept, emulate or redirect the communication protocols used by Microburst Software, DEECA and Councils in any way, for any purpose, including without limitation unauthorised generation of Blue Factor reports, calculation of Blue Factor scores or calculation of ‘STORM’ scores.
Prohibition on Reverse Engineering, Decompilation, and Disassembly
You may not reverse engineer, decompile, disassemble or create derivative works based on the whole or any part of Blue Factor, except and only to the extent that such activity is expressly permitted by applicable law notwithstanding this limitation.
You agree that you will not repeatedly run Blue Factor with incremental changes with the intent or for the purpose of extracting or ‘mining’ data from the tool or any other purpose other than that for which it is intended.
Support Services.
Microburst Software and DEECA may provide you with support services related to Blue Factor ("Support Services") but is under no obligation to do so. Any supplemental software code provided to you as part of the Support Services shall be considered part of the Blue Factor and subject to the terms and conditions of this agreement.
Compliance with Applicable Laws
You must comply with all applicable laws regarding use of Blue Factor.
Rental
You may not rent, lease, loan, merge, adapt, vary or modify Blue Factor.
Assignment
You may not assign or otherwise transfer this license or any of your rights or obligations arising under it, without Microburst Software's prior written consent.
Termination
Without prejudice to any other rights, Microburst Software may terminate this agreement if you fail to comply with the terms and conditions of the agreement. In such event, your access to Blue Factor will be revoked and you must immediately cease all activities authorised by this license agreement. All rights granted to you under this agreement will immediately cease, however, the rights and obligations of the parties which by their nature survive termination or expiration of this license shall remain in full force and effect.
No warranties
Microburst Software expressly disclaims any warranty for Blue Factor. Blue Factor is provided 'As Is' without any express or implied warranty of any kind, including but not limited to any warranties of merchantability, non-infringement, or fitness of a particular purpose.
Microburst Software does not warrant or assume responsibility for the accuracy or completeness of any information, text, graphics, links or other items contained within Blue Factor.
Microburst Software makes no warranties respecting any harm that may be caused by the transmission of a computer virus, worm, time bomb, logic bomb, or other such computer program.
Microburst Software further expressly disclaims any warranty or representation to Authorized Users or to any third party. The originator of any design assessed using Blue Factor remains entirely responsible for the corresponding design and Microburst Software accept no responsibility or liability associated with the above, or any changes that may be made arising out of use of Blue Factor and associated documentation.
Limitations of liability
Blue Factor has been provided for the purpose of information and communication. It is not intended to be, and should not be relied upon as, the ultimate and complete source of information on any particular topic. While we make every effort to ensure that material on this site is accurate and up to date (except where denoted as ‘archival’), this material does in no way constitute the provision of professional or specific advice. You should seek appropriate, independent, professional advice before acting in any of the areas covered.
By entering Blue Factor, you will be deemed to have released and discharged Microburst Software, DEECA and Victorian councils from all liability in respect of any loss suffered as a result of relying on the information on this site. By entering this site, you will be assuming all risks associated with the use of this site.
Microburst Software shall have no liability with respect to the content of Blue Factor or any part thereof, including but not limited to errors or omissions contained therein, libel, infringements of rights of publicity, privacy, trademark rights, business interruption, personal injury, loss of privacy, moral rights or the disclosure of confidential information.
Microburst Software, DEECA and Victorian councils do not guarantee, and accept no legal liability whatsoever arising from or connected to, the accuracy, reliability, currency or completeness of any material contained on Blue Factor.
Microburst Software, DEECA and Victorian councils accept no responsibility for information on other websites, even where links have been provided from Blu Factor. It is the responsibility of the user to make their own decisions about the accuracy, currency, reliability and correctness of information contained in linked external websites. Links to external websites do not constitute a recommendation or endorsement of any product, information or service contained on that website.
In no event shall Microburst Software, DEECA or Victorian Councils be liable for any damages (including, without limitation, lost profits, business interruption, or lost information) arising out of 'Authorized Users' use of or inability to use Blue Factor, even if Microburst Software has been advised of the possibility of such damages.
In no event will Microburst Software be liable for loss of data or for indirect, special, incidental, consequential (including lost profit), or other damages based in contract, tort or otherwise.
Information on this website does not necessarily reflect the views of Microburst Software, DEECA or Victorian councils.
Last updated: 5th November 2025
Privacy
Microburst Software, the Department of Energy, Environment and Climate Action (DEECA) and Victorian councils, responsibly collect and handle personal information. Microburst Software, DEECA and Victorian councils are committed to complying with the Privacy and Data Protection Act 2014.
Collection of information is also governed by the DEECA Privacy Policy and the relevant Council’s privacy policies. These Privacy Policies may change from time to time and changes will take effect from the date of posting on their website. These Privacy policies are available on the DEECA and Council websites or upon request.
Collecting personal information
Personal information is information about you, from which your identity could reasonably be ascertained.
You can visit and browse this website without disclosing your personal information, other than that which is requested to register on the website. Microburst Software, DEECA and Victorian councils, through the Blue Factor website, do not retrieve or collect personal information, except where that information is freely given, for example:
- Registering to use Blue Factor
- Contacting us through this website.
Microburst Software collect personal information through Blue Factor only when it is necessary for its function or services, including information needed to manage or administer those functions and services.
Information provided in the registration process and when completing a Blue Factor report may be accessed by Microburst Software, DEECA staff or council staff from the municipality in which the project is located.
Microburst Software, DEECA and council staff that access the information on the Blue Factor website collect and handle your personal information in accordance with the privacy principles in the Privacy and Data Protection Act 2014.
Cookies
A cookie is information that is shared between a web server and a user's browser. Cookies give the server information about a user's identity and website visiting patterns and preferences.
Cookies may be issued when you log into Blue Factor. You can change your internet settings to allow all cookies, notify you when one's issued or not accept them at all. You can also delete cookies at any time. If you have your cookies disabled in your browser, you will still be able to access this website.
If you don't allow our cookies or delete them you will need to re-enter your username and password each time you login to the Blue Factor website. The cookie does not record your login password.
Google Analytics
Our website collects information through Google Analytics.
For statistical and system administration reasons, Google Analytics automatically records some of your computer information such as:
- the Internet Protocol (IP) number (the IP number is assigned to your computer when you use the internet)
- the domain name of the account you use to access the internet (eg. "your-university.edu.au" or "your-department.gov.au")
- the date and time of your visit to the site
- the pages you accessed and downloaded
- the address of the last site you visited, and
- the type of browser you are using, for example, Firefox or Internet Explorer.
This information will only be used for internal statistical purposes, to update and improve our website and occasionally to assist in providing helpdesk support. To the extent that this data could make you identifiable, MAV and CASBE member councils will not attempt to identify individuals from the records the server automatically generates unless that is necessary to investigate a breach of law or regulation.
Data Quality and Security
Microburst Software, DEECA and Victorian councils will take reasonable steps to protect the personal information they collect through the Blue Factor website. However, while Microburst Software, DEECA and Victorian councils will strive to protect your personal information, they cannot ensure or warrant the security of any information transmitted to them online.
Access
You have a right to access the personal information about you held by public entities. In accordance with the Act, requests for access to data about you held by DEECA or a Council should be made via formal application under the Freedom of Information Act 1982 (Vic).
In certain circumstances requests may be dealt with by DEECA or a council without the need to make formal application.
Charges may apply to cover the cost of accessing and providing this information to you.
Requests for access should be sent to DEECA or council via the contact details listed at the bottom of this Privacy Statement.
Contact us
Any questions relating to this Privacy Policy or your personal information can be directed to
Last Updated – 5th November 2025
Infiltration helps recharge groundwater and sustain baseflows in waterways.
Infiltration contributes towards the infiltration/filtered flows objective.
The soil type chosen is used to estimate infiltration into the underlying soils beneath the corresponding WSUD asset.
Since most assets infiltrate at depth, it should be considered whether such soils are present at a depth of 0.5 m or more.
Across much of the state and most of Melbourne, the most common soil types are clays, particularly for deeper underlying soils.
Therefore, clay should usually be adopted in most cases in most municipalities.
Other soil types should only be used where there is desktop or measured geotechnical evidence that soils such as sands or loams that are more freely draining are present. Examples where these may occur include:
- Coastal areas that are sandy (e.g. Mornington Peninsula and inner suburbs in Port Phillip, Bayside, Kingston and Frankston) - Sand
- Agricultural areas with sandy or loamy soils such as around Clyde and Officer - Sand
- Large desert areas near the western border of the state - Sand
- Many alpine areas - Sandy loam
Some assets may be lined and will have no infiltration. Examples include:
An above ground raingarden planter box
A raingarden that is lined to prevent infiltration
The same soil type should usually be used for all assets within a given site. The exception to this may be where some assets may be unlined but others may be lined due to design or configuration.
The infiltration rate is assumed to be at the lower end of the textbook range for each soil type as follows:
- 0 mm/hour for lined
- 0.36 mm/hour for clay
- 3.6 mm/hour for sandy clay
- 36 mm/hour for sandy loam
Several councils offer a voluntary in-lieu stormwater contribution scheme, sometimes also referred to as a stormwater offset.
For example, Kingston, Moonee Valley and Mornington Peninsula.
The intention of these is to recognise that in some very constrained high density sites it may be practically very difficult or financially very costly to meet the objectives onsite.
The in-lieu scheme provides a voluntary alternative pathway that a developer may opt into to achieve compliance where this is allowed by Council.
The contribution or offset rate is based on the area and type of development. Usually, but not always, there is a set charge per square metre of impervious area.
The stormwater offsets are generally designed to offset shortfalls in meeting the total nitrogen load reduction objective. In effect, Council take on the obligations of the developer to meet the nitrogen load objective by delivering other projects with the contributions received. It is generally implied that in meeting the nitrogen objective, the total suspended solids and total phosphorus loads would also be met since these are usually readily achievable through typical offset projects.
Reliance upon an in-lieu scheme does not diminish the developer's general environmental duty to ensure that they have:
1. Done everything reasonable and practical to minimise the risk of harm to the environment and to meet the range of stormwater objectives.
2. Considered and either eliiminated or mitigated risks that may be present beyond those for a typical urban development. For example a factory, petrol station or shopping centre may have above average risks for heavy metals, hydrocarbons or litter pollution respectively. These should be separately addressed and offsets should be used with careful consideration of these risks.
Some Councils require a minimum threshold to be met through on-site WSUD before using offsets. For example, City of Moonee Valley require a minimum STORM/Blue Factor score of 80% with a proportion of the remainder up to 20% that can be offset.
Other limitations may also be imposed such as certain development types, limitation on the size of development or where discharging to sensitive sites or receiving waters.
Blue Factor estimate of stormwater quality in-lieu contribution
If a Council stormwater quality in-lieu scheme is available and any minimum threshold has been met, Blue Factor will provide an estimate of the in-lieu contribution and an option to 'Apply offset' to achieve compliance.
Blue Factor will then provide an updated report with a '100% STORM/Blue Factor score' and an estimate of the in-lieu contribution or offset cost.
Note that compliance through this pathway is conditional upon payment of the in-lieu contribution for compliance to have been achieved.
The final cost is subject to calculation and confirmation by Council and their calculation will be taken as final.
Whilst all reasonable efforts are made to ensure the accuracy of the Blue Factor tool, we do not guarantee the accuracy of the financial calculations and it is recommended to confirm with Council any in-lieu contribution payment that may be payable.
Note: Blue Factor only provides estimates for 'Development applications' and not 'Subdivision applications' at this time. Users should refer to the relevant Council calculator for subidivision applications (e.g. Mornington Peninsula).
Further information on existing stormwater in-lieu schemes and eligibility may be found below:
City of Moonee Valley
https://mvcc.vic.gov.au/work/my-development/wsud-voluntary-contribution-scheme-eligibility-tool/
City of Kingston
Stormwater requirements: https://www.kingston.vic.gov.au/property/property-management/drains-and-stormwater/stormwater-requirements-for-developers#section-2
Mornington Peninsula Shire
https://www.mornpen.vic.gov.au/Environment/Water/Stormwater-Quality-in-lieu-Contribution-Scheme
Melbourne water also offer a stormwater offset program. This is available for areas with Melbourne Water's jurisdiction that are not located within either:
- A drainage scheme; or
- A municipality that offers a stormwater in-lieu scheme.
Some Melbourne Water drainage schemes also incorporate a stormwater offset to address shortfalls.
The intention of the stormwater offset program is to recognise that in some very constrained high density sites it may be practically very difficult or financially very costly to meet the objectives onsite.
The stormwater offset program provides a voluntary alternative pathway that a developer may opt into to achieve compliance where this is allowed by Council and Melbourne Water.
The offset rate is usually based on the area developed and the development type.
The stormwater offsets are generally designed to offset shortfalls in meeting the total nitrogen load reduction objective. In effect, Melbourne Water take on the obligations of the developer to meet the nitrogen load objective. It is implied that in meeting the nitrogen objective, the total suspended solids and total phosphorus loads would also be met through the offset program since these are usually more readily achievable through typical offset projects.
Reliance upon an in-lieu scheme does not diminish the developer's general environmental duty to ensure that they have:
1. Done everything reasonable and practical to minimise the risk of harm to the environment and to meet the range of stormwater objectives.
2. Considered and either eliminated or mitigated risks that may be present beyond those for a typical urban development. For example a factory, petrol station or shopping centre may have above average risks for heavy metals, hydrocarbons or litter pollution respectively. These should be separately addressed and offsets should be used with careful consideration of these risks.
A Melbourne Water offset may be estimated at the using the calculator at the following link:
The STORM or Blue Factor score calculated by Blue Factor may be used as an input to the calculator for the question: 'What percentage of best practice of stormwater treatment are you achieving on site?'
Blue Factor does not calculate the Melbourne Water stormwater offset directly.