Stormwater Requirements for Melbourne Homes: A Builder's Guide
If you are building, extending or renovating in Melbourne, stormwater is one of those topics that rarely comes up until a permit stalls. The short version: rainwater that lands on your property must be collected on site and sent to an approved legal point of discharge. Depending on your council and your block, you may also need a water sensitive urban design (WSUD) assessment, a rainwater tank, flood-level advice or approval to build near drains and easements. Here is how the pieces fit together, so you can plan for them early rather than discover them late.
TL;DR
You are responsible for the stormwater on your property. It must be collected on site and discharged to the legal point of discharge your council nominates.
A legal point of discharge report is needed under the Building Regulations 2018 when building work includes a stormwater drainage system, and your building surveyor will ask for it.
Many councils expect a WSUD or STORM report for extensions and new dwellings. City of Melbourne, for example, asks for a STORM rating of 100 per cent or more.
Flood overlays, easements and nearby Melbourne Water drains can add approvals, so check your property before the design is locked in.
Rules differ from council to council. Always confirm the current requirements with your own council and Melbourne Water.
Table of Contents
Who sets the rules: council, Melbourne Water and you
Stormwater in Melbourne is managed in layers, and knowing which layer your site touches tells you who to ask.
Your council is generally the local drainage authority. It looks after the smaller drains in the street, such as kerbs and channels, pits and underground pipes in roads and drainage easements. Melbourne Water manages creeks, larger main drains and floodplains across greater Melbourne. You, as the owner, are responsible for the drains and pipes on your own property.
Runoff usually travels the same way water always does: from your roof and paving downhill into the council drain, then into a larger Melbourne Water drain, and eventually into a creek. Each handover point has its own rules.
There is also your building surveyor. Under the Building Regulations 2018, surveyors must consult Melbourne Water before issuing a building permit in certain situations, so that flooding and the impact on waterways or drains have been considered. If you want the wider permit picture, our guide to building permits in Melbourne explains how the surveyor fits in.
The legal point of discharge
The legal point of discharge (LPD) is the spot where your property’s stormwater is allowed to leave your land and enter the public drainage system. Your council nominates it, and it is not always where you would guess. On a sloping Melbourne block, the nominated point might be a kerb outlet at the front, a pit in a rear easement or a connection into a council pipe.
A few things to know:
It is required for building work with a stormwater system. Regulation 133(2) of the Building Regulations 2018 calls for a legal point of discharge report when the work includes a stormwater drainage system. In practice, that covers most extensions and every new build.
It follows the council’s rules on how water gets there. City of Melbourne, for instance, only accepts discharge to the nominated point by gravity. If your new floor level or basement sits below that point, pumped systems need a conversation with the council first.
Triggers are broader than a brand-new house. Yarra City Council asks for a report and consent when the existing system is altered, when stormwater volume or flow rate increases, when a new dwelling is built, or when an extension increases runoff.
It has a shelf life. Yarra states that the report and consent are valid for 12 months and approved plans for 18 months. If your project drifts, you may need to reapply.
Fees and turnaround times vary. At the time of writing, City of Melbourne publishes a report fee of $164.20 with a determination within 10 business days, and Yarra quotes a response time of 10 to 15 business days for single dwellings. Check your council’s page for the current figures, because they change.
To apply, councils typically want a title plan, a dimensioned site plan, a feature and level survey, and civil stormwater plans showing downpipes, pits, any pump-well and WSUD elements, plus floor plans showing the connection to the discharge point. Having your designer prepare these together saves a lot of back and forth.
WSUD and STORM reports: treating the water you send away
Collecting stormwater is only half the job. Councils also want to know that runoff leaving your site is cleaner and slower than it would be from a bare roof and a big slab. That is what water sensitive urban design is about.
The Melbourne Planning Scheme requires WSUD in the design of buildings and works. Planning applications are expected to meet best-practice water quality targets: an 80 per cent reduction in total suspended solids, 45 per cent in total phosphorus, 45 per cent in total nitrogen and 70 per cent in litter.
What is a STORM report?
STORM (Stormwater Treatment Objective, Relative Measure) is a free online calculator that many Victorian councils accept for smaller projects. You enter your roof area, paved areas and the treatment you plan to use, such as a rainwater tank connected to toilets or a raingarden, and it produces a score. A score of 100 per cent or more meets the standard. City of Melbourne requires that rating for compliance, and its calculator can produce a report for extensions, single dwellings, units and townhouses.
When do you need one?
If your changes may affect the quality or amount of stormwater leaving the property, City of Melbourne asks you to submit a WSUD report. Other councils set their own thresholds. A commonly used trigger is an extension that adds around 50 square metres of hard surface, though that is not universal and you should confirm it with your council. City of Melbourne’s drainage guidelines also exempt residential extensions and single dwellings adding less than a certain amount of floor area from some integrated water cycle requirements, so a small renovation may face a lighter process than a new build.
Choosing the right treatment
City of Melbourne suggests weighing the space you have, site levels relative to the discharge point, ease of maintenance, upfront and lifecycle costs, and extra benefits such as an alternative water supply. On a tight inner-city lot, a tank under a deck may be the only realistic option. On a larger suburban block, a raingarden and more permeable ground cover may do the job more cheaply. Melbourne Water’s guidance points the same way: keep as much ground pervious as you can, and use rainwater tanks plumbed to toilets and household raingardens.
This is a decision for the design stage. Pushing it to after the plans are drawn is how a courtyard becomes a tank problem.
Rainwater tanks and on-site detention
Rainwater tanks
In Victoria, many new homes and renovations are asked to include a rainwater tank as their stormwater response. The common benchmark in the BESS sustainable design fact sheets for a single dwelling is a tank of at least 2,000 litres, connected to at least 50 square metres of roof and plumbed to all internal toilets. Whether this applies to you depends on your council’s planning policy and your permit conditions, so treat it as a starting assumption and confirm it.
Plan for the tank’s location early. It needs a roof catchment that drains to it, a place to sit (beside the house, under a deck, or buried) and plumbing back to the toilets.
On-site detention (OSD)
Some sites, particularly where a council drain has limited capacity, need on-site detention: a way of holding stormwater temporarily and releasing it slowly. City of Melbourne’s guidelines describe a system with three parts:
A runoff collection system: gutters, downpipes, pits and pipes.
A storage area, such as an oversized pipe or a tank.
A flow control device, which releases water to the legal point of discharge at a set rate.
The storage volume is worked out by a drainage designer using a formula that includes an allowance for climate change, which City of Melbourne sets at 18.5 per cent higher rainfall intensity. This is not a calculation for guesswork. It belongs with a hydraulic or civil engineer.
Flood overlays and overland flow paths
Stormwater does not only run through pipes. In a heavy storm, water follows overland flow paths along streets, driveways and between houses. Councils map these with planning overlays such as the Special Building Overlay (SBO), the Land Subject to Inundation Overlay and the Urban Flood Zone.
If your land sits under one of these:
A planning permit is needed for building or renovation works. The SBO specifically captures land affected by 1 in 100 year overland flow paths.
Melbourne Water states that where land is subject to flooding or near its assets, the council will not issue a planning or building permit until Melbourne Water has reviewed and approved the plans.
Flood level requirements can shape the design. City of Boroondara, for example, requires the finished floor level to sit above the identified flood level with an extra 300 mm of freeboard, plus setbacks from overland flow paths, and charges an assessment fee ($310.00 in 2025-26).
A flood level statement from Melbourne Water may be required for the Building Code of Australia, and Melbourne Water describes it as a free service taking 14 days.
These steps add weeks, and they are far easier to absorb at the start than mid-project. We have written more about this in our guide to building on a Melbourne flood overlay and about checking planning overlays on VicPlan.
Easements and drains under or near your build
Many Melbourne blocks, especially older ones, carry a drainage easement: a strip where a pipe serves your property and your neighbours’. Councils protect these carefully.
Maroondah City Council’s guidelines are a useful example of how strict the rules can be. Works over an easement are unlikely to be approved when it carries overland flows, holds water in a storm or contains a hydraulically critical drain. Where building over is possible, its minimum clearances include:
footings founded 200 mm below a 45-degree line from the invert of any stormwater pipe
600 mm horizontal clearance from the pipe
500 mm minimum cover to the top of the council drain
2,700 mm vertical clearance for eaves over the easement
Those numbers are one council’s. Yours may differ, which is why you should ask early. If an easement runs through your site, our builder’s checklist for building over an easement walks through the questions to settle before design is final. Boundary walls bring their own stormwater and drainage questions too, covered in our piece on building on a boundary.
Connecting to a Melbourne Water drain
Most homes connect to a council drain. If your property backs onto a creek, open drain or a Melbourne Water main drain, though, a different process applies. Melbourne Water requires formal approval before any new or modified stormwater connection into its drains, waterways or open channels. The technical requirements differ depending on whether you are building an inlet (into underground drains) or an outlet (into an open waterway or drain).
For an inlet, Melbourne Water’s standard calls for the connection to be angled at 45 degrees, or as close as achievable, downstream, and set in the middle third of the drain. Works on its assets must be done by preferred contractors who hold a Permit to Work. That is not a job for a general plumber on a Friday afternoon.
The application is also tied to your drainage scheme. Melbourne Water offers a map to find your drainage scheme if you are planning a development in greater Melbourne.
How to check what applies to your site
Before a designer draws anything, a few checks give you the lay of the land:
Planning overlays. Look up your property on VicPlan for flood-related overlays. Our planning permit guide explains what comes next if one applies.
Melbourne Water flood information. You can request a flood level statement from Melbourne Water for free, which takes about 14 days. Property flood information is also available through LANDATA or Dye & Durham, at about $50 and around 10 days.
Assets near your property. Dial Before You Dig is a free service that shows whether Melbourne Water assets are on or near your land.
Your council’s stormwater page. Look for the legal point of discharge application, its fee, what plans it wants and whether a WSUD report is needed.
Your title. It shows easements. Ask whoever is designing your project to read it with you.
Then set the right order of play. The legal point of discharge and WSUD assessment generally need to be sorted before or alongside your building permit application, and the town planning process may come first. Our six-step guide to the town planning process and guide to renovation building permits show where stormwater slots in.
How we handle stormwater on a Yorcon project
Stormwater is exactly the sort of detail that gets lost between a designer, an engineer, a surveyor and a council. Our approach is to manage the whole process, from design through permits and approvals to construction, so these requirements are identified at the start and built into the plans instead of showing up as surprises.
If you are planning a home extension, a major renovation or a design and build project, we can talk through your site’s drainage, overlays and easements before you commit to a design. Our architectural house designs are offered from $15,000 to $35,000 as a one-off. If your home is older, our heritage home renovation and restoration service takes into account how drainage and character interact on older streets.
Not sure where to start? Book a free project feasibility call and we will help you work out which stormwater steps are likely to apply to your block.
A realistic order of work
Here is the sequence we would suggest for most Melbourne projects:
Feasibility. Check the title, overlays, easements and flood information.
Concept design. Position the building, hard surfaces, tank and any raingarden with drainage in mind, not as an afterthought.
WSUD or STORM assessment. Run the numbers and confirm the design reaches the required score.
Planning permit, if required. Overlays, heritage controls and neighbourhood character can all trigger one.
Legal point of discharge report and consent. Apply with your stormwater plans, and allow for your council’s response time.
Building permit. Your surveyor checks that the documentation is complete, and may consult Melbourne Water.
Construction and inspection. Drainage is installed and inspected as the build progresses, and your documentation is finalised.
Council timeframes and fees change, so confirm current figures at each step rather than relying on any guide, including this one.
FAQ
Do I need a legal point of discharge report for a small extension?
If the building work includes a stormwater drainage system, the Building Regulations 2018 require one. Some councils, such as Yarra, also ask for it whenever an extension increases runoff. Check with your council, because a small addition can still change where water goes.
Do I need a STORM report for my renovation?
It depends on your council and the scale of the work. City of Melbourne asks for a WSUD report when changes may affect the quality or amount of stormwater, and requires a STORM rating of 100 per cent or more. Other councils often set a threshold based on added hard surface area.
Do I have to install a rainwater tank?
Often, yes, for new single dwellings and larger renovations, but it is set by your council’s policy and permit conditions. A common benchmark is a tank of at least 2,000 litres connected to 50 square metres of roof and to the toilets. Ask your council or designer what applies to your site.
Can I build over a drainage easement?
Sometimes, with council consent and strict clearances. Councils are unlikely to approve works over an easement that carries overland flows or a critical drain. Raise it before design is finished, since it can change where the house sits.
How do I find out if my property is flood-prone?
Check planning overlays on VicPlan and request a flood level statement from Melbourne Water, which is free and takes about 14 days. Your council can also confirm whether the Special Building Overlay or another flood control applies.
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