City of South Perth - New Drainage/Stormwater Requirements

New Drainage/Stormwater Requirements

Information on requirements for new stormwater / drainage connections.

Last updated on: 17 May 2024

In this article

Stormwater disposal
Which stormwater disposal should I use?
Stormwater design guidelines
Stormwater drainage approval
Stormwater applications
Raise a request

Stormwater disposal

The two methods of stormwater disposal are:

Soakwells. Stormwater is discharged on the property via soakwells.
Connecting to drainage. Stormwater collected from the roof and pavement of the property is discharged via a connection to the City's or water provider's drainage system.

Which stormwater disposal should I use?

Your site will determine the most effective method of stormwater disposal. Storing stormwater runoff for re-use is encouraged.
A Geotechnical Consultant will recommend a stormwater disposal method after an investigation of the site.
Stormwater disposal methods are influenced by the following:
High water table.
Soil infiltration rates.

Soakwells

Soakwells are the suitable stormwater disposal method when stormwater is to be discharged on-site via soakwells or on-site disposal
Soakwells are underground tanks that allow water to gently seep into the surrounding soil
They are generally suitable for sandy sites with no underlying clay or silt content
Soakwell sizes can be varied to achieve the required capacity; however in some districts soakwell depth may be restricted due to a high ground water table
Soakwells should be interconnected to provide relief if one tank reaches capacity.

Connecting to drainage

Soakwells are generally not the suitable stormwater disposal method when connecting to the City drainage network
To ensure stormwater disposal is effective, lots will generally require interconnected sumps connected to the local drainage network
Sumps are solid underground tanks that hold water instead of allowing it to seep into the surrounding reactive soil
They should be interconnected at the base and must be connected into a local drainage network to enable the tanks to empty
In most new developments silt pits and lot connections are provided at subdivision, but in some older areas a new connection may be required to accommodate infill development (e.g. units).

Stormwater design guidelines

See the Stormwater Drainage for Proposed Buildings Design Guidelines.

Stormwater drainage approval

Stormwater drainage approval is required to:

Limit the effects of high density urban development on drainage infrastructure
Improve the quality of stormwater entering the lakes, river system and groundwater
Ensure that the most appropriate form of stormwater disposal is utilised in each area.

Stormwater applications

Submit a stormwater drainage application online via the mySouthPerth portal. You will need to have a design or site plan (mandatory) and other supporting documents to complete your application.

Raise a request

For any queries about stormwater requirements or applications, raise a request below
An officer will investigate and respond within 10 working days.

New Drainage Enquiry

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