Stormwater quality targets

If you want to connect to or develop a property that connects to one of our stormwater assets or natural waterways, you must meet our stormwater quality targets.

This makes sure we protect the health of our waterways by minimising the environmental impacts of urban stormwater run-off.

Stormwater quality improvements aren't new. They were already required for multi-dwelling developments. 

Until now, these requirements were set and managed by councils. However, each council had a different set of conditions across our area of operations.

We want to make the connection process as simple as possible.

So you can easily see our standards for the quality of stormwater entering our system, we're making our requirements clearer and adopting a Stormwater quality targets policy.


Check out the free Small Scale Stormwater Quality Model (S3QM) tool to see if your proposal meets these standards.

The targets apply to certain types of development that connect to a Sydney Water stormwater asset or natural waterway. 

These include (but are not exclusive to): 

  • residential developments that are part of a greater subdivision resulting in more than two single, attached or semi-detached dwellings, eg free-standing houses, duplexes, terraced houses
  • residential development for multi-dwellings or units that are under strata management, eg townhouses, villas, apartments
  • developments that are commercial, industrial or are a special use building or structure, eg a community, education or recreational building
  • developments or infrastructure that have state significance.


You may be exempt from meeting these targets if:

  • the original total site area of your development is less than 250 m2
  • you're refurbishing an existing building and maintaining the existing drainage system.

The minimum stormwater quality targets are:

Pollutant Average annual pollutant load reduction objective (%)1
Gross pollutants (>5 mm) 90
Total suspended solids 85
Total phosphorous 60
Total nitrogen 45

1 Pollutant removal design criteria adopted from Western Sydney Growth Centres – Stormwater Guidance for Precinct Planning (Prepared by DEC Nov 2006).

Use the free Small Scale Stormwater Quality Model tool to see if your proposal meets the standards.

To use the tool:

  1. Open the Small Scale Stormwater Quality Model tool
  2. Set up a user account
  3. Enter the details of your development and your proposed stormwater quality improvement device or treatment train
  4. Receive a ‘Deemed to comply’ certificate if your proposal meets the criteria.


Sometimes, you will still need an eWater MUSIC model. Read our 
Stormwater quality targets policy to find out more.