Water Sensitive Urban Design — a practical Victorian guide.
How WSUD requirements apply to inner-suburban infill, outer-growth subdivisions, and regional Victorian development. The measures, the modelling, and what councils and Melbourne Water expect to see.
Integrating stormwater into the built environment.
Water Sensitive Urban Design (WSUD) is an approach to planning and designing urban developments that integrates the management of the water cycle — stormwater, groundwater, and potable water — into the built environment.
Across Victoria, WSUD is required for many new developments as a condition of planning permits. Melbourne Water and local councils use WSUD requirements to ensure that new development does not increase pollutant loads or runoff volumes entering the local waterway network.
Sensitive waterways, tight sites.
Inner Melbourne councils — Yarra, Stonnington, Port Phillip, Boroondara, Melbourne — apply strict WSUD requirements due to the sensitivity of urban waterways like the Yarra River, Merri Creek, and Moonee Ponds Creek.
Common WSUD measures for inner-suburban infill:
- Rainwater tanks plumbed to toilet flushing and external taps
- Rain gardens (bioretention systems) within streetscape or front setbacks
- Permeable paving for driveways and car parks
- Green roofs or walls where structurally feasible
- Connection to recycled water schemes where available
On tight inner-city sites, achieving WSUD compliance often requires creative design. The combination of a rainwater tank plus a small rain garden plus permeable paving typically delivers STORM ≥100% on a constrained lot without losing developable area.
Drainage-scheme-coordinated treatment.
In Melbourne's outer growth corridors — Wyndham, Melton, Whittlesea, Hume, Casey, Cardinia — WSUD requirements are shaped by Melbourne Water's Port Phillip and Westernport Drainage Schemes.
Greenfield developments in these areas typically must:
- Demonstrate STORM score ≥100% (best-practice pollutant reduction)
- Provide an integrated water management plan for larger subdivisions
- Include retarding basin and wetland design at estate scale
- Consider stormwater harvesting and reuse where feasible
- Coordinate treatment with the broader Melbourne Water drainage scheme
The treatment elements you'll see on Victorian development sites.
- Rain gardens (bioretention systems)
- Planted stormwater treatment systems that filter pollutants through engineered soil before discharge. Effective at TSS, TP, TN reduction at lot and street scale.
- Rainwater tanks
- Capture roof runoff for reuse in toilets, laundry, and irrigation. Demand-side benefit reduces post-development discharge as well as supplying non-potable water.
- Permeable paving
- Allows stormwater to infiltrate through the surface, reducing runoff volume and providing some pollutant capture. Suits driveways, car parks, and shared paths.
- Constructed wetlands
- Estate-scale treatment systems used in larger subdivisions; coordinate with Melbourne Water drainage scheme design.
- Gross pollutant traps
- Mechanical devices that capture litter and coarse sediment from stormwater. Often a first-pass element of an industrial or commercial treatment train.
- Bioretention basins
- Larger-scale rain gardens; common in subdivision treatment trains and on commercial sites with available space.
Frequently asked about WSUD in Victoria.
When is WSUD required for a Victorian development?
Most Victorian planning permits carry a WSUD condition. The trigger is typically Clause 56.07-4 of the Victorian Planning Provisions for residential subdivisions, Clause 53.18 for non-subdivision development, or a council-specific local policy. If the permit references EPA Publication 1739.1 or "best-practice stormwater treatment", a WSUD requirement is the deliverable.
What does STORM ≥100% mean?
STORM is a tool for scoring residential WSUD compliance against EPA Publication 1739.1 best-practice targets. A score of 100% indicates the treatment train delivers the standard pollutant load reductions (80% TSS, 45% TP, 45% TN). Most Victorian councils require STORM ≥100% as the compliance threshold.
Which WSUD measures work for tight inner-suburban sites?
On constrained inner-city sites, the most effective combination is typically a rainwater tank plumbed to toilet flushing and external taps, a small rain garden in the front setback, and permeable paving across driveways. The combination delivers STORM ≥100% on most lot configurations without compromising the developable area.
What is different about outer-growth subdivisions?
Outer-growth corridor sites — Wyndham, Whittlesea, Hume, Casey, Melton, Cardinia — typically sit within Melbourne Water Port Phillip and Westernport Drainage Schemes. Treatment train design has to coordinate with estate-scale wetlands, retarding basins, and the broader scheme drainage logic, not just the lot-scale compliance score.
When is MUSIC modelling required instead of STORM?
MUSIC modelling is used for larger subdivisions, sites near sensitive waterways, or where the council scheme specifically requires detailed water-quality modelling. Some councils default to MUSIC for any site above a certain area threshold. We confirm during site analysis which tool the project will use.