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Stormwater for builders and developers

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Stormwater for builders and developers

Council's plans and codes

The primary documents which relate to stormwater for developments are Council's Development Control Plan and Stormwater and On-site Detention Code.

Section 2.17 of the DCP specifies requirements for specific developments to meet water conservation and stormwater quality targets that have been established for the Marrickville Council area. Section 2.22 of the DCP provides a description of flood affected areas within the Marrickville Council area and relevant development controls.

Council's Stormwater and On-site Detention Code is intended to provide a clear statement of policy, requirements and methods relating to stormwater drainage for residential, commercial, industrial and all other types of development.

Typical Development Application requirements

Each development will have different requirements depending on the type of development and site specific circumstances. However a Stormwater Drainage Concept Plan will typically be required for all new buildings and for alterations and additions that involve changes to stormwater drainage.

The Stormwater Drainage Concept Plan must illustrate how rainwater will be managed on site. Council should be contacted about the drainage requirements that apply to the site before the drainage plan is prepared. Typically if the impervious area (hard surfaces) of a property is increased by more than 40m² then on-site detention (OSD) of stormwater will be required.

The Erosion and Sediment Control plan must show how erosion will be prevented from a construction site and how washing or blowing of sediment into adjoining land or into Council's stormwater drainage system will be avoided.

Legal points of discharge

The property owner is responsible for connection of a properties stormwater system to a legal point of discharge. 

The Building Code of Australia provides technical standards for all aspects of building. With relation to stormwater the Building Code of Australia references Australian Standard AS/NZ 3500 Plumbing and drainage.

Australian Standard AS/NZ 3500.3  states that roof water and surface water should be collected and discharged through underground pipes to legal points of discharge including:

  • Council's public drainage system including the roadside kerb and gutter
  • Inter-allotment drainage systems

Where a property slopes to the road, typically a new connection is installed to the roadside kerb and gutter. When installing a new connection across Council's footpath to the gutter, the person undertaking the works is required to gain approval from Council. The Approval to Excavate Council Roads and Footpaths Application Form is available on Councils website.

Where a property slopes away from the road an easement to drain through neighbouring properties to Council's public drainage system is typically required. In this case the owner is responsible for negotiations with the neighbouring owners to establish an easement. A drainage easement generally incorporates a drainage pipe, and may also include an overland flow path.

If a lot drains to non-Council owned stormwater systems, such as Rail Corp or Sydney Water, the developer will have to seek approval from the relevant authority to connect to their system.

Stormwater may not be discharged to the sewer.

Depending on the circumstances, fines up to $20,000 may be issued for illegal connections.

Maintaining overland flow paths

Overland flow paths are an integral part of the drainage system. Overland flow paths are to be preserved, or alternatives provided, wherever they pass through or affect the development site.

To this end, buildings, solid fences and other structures should not be built across overland flow paths unless an acceptable alternative is provided.

Building near or over Council's stormwater assets

Council manages the public stormwater system which is sometimes located in drainage easements on private property and sometimes on private property without easements.

If a development impacts Council's stormwater assets, either by building near or over an asset, it is likely Council will require the developer to undertake special measures to protect Council's assets and ensure its continued function in the future.

Applicants are encouraged to arrange formal discussions with Council officers prior to lodging a development application to address likely issues and opportunities based on the unique circumstances of their site prior to finalising the design of the development. To do this contact Council's Development Engineer on 9335 2225 during normal business hours.

Frequently asked questions

Does Council have records of stormwater on private property?

Council maintains records of its stormwater assets which can be provided on request when required but does not maintain records of private stormwater systems.

How can I tell if a property is flood affected?

Section 2.22 of the DCP provides a description of flood affected areas within the Marrickville Council area and relevant development controls. The DCP is available on Council's website.

Not all of Council's flood affected properties are currently mapped as Council has not undertaken flood studies in all areas. Council also has some flood studies that are currently in draft edition or have not yet been formally adopted.

The property I'm building on does not have an outlet to the road. What can I do?

The property owner is responsible for connecting property drainage to Council's stormwater system. If you need to connect your stormwater system to the road gutter, you will need to fill and submit an Approval to Excavate Council Roads and Footpaths Application Form which is available on Council's website.

What stormwater information needs to be submitted as part of a Development Application?

Each development will have different requirements depending on the type of development and site specific circumstances. However a Drainage Plan and Erosion and Sediment Control Plan will typically be required for all new buildings and for alterations and additions that involve changes to stormwater drainage.

When redirecting and/or concentrating stormwater flows, property owners are required to collect the stormwater and direct it to a legal point of discharge.

More information

This is one of three pages providing information on stormwater management for residents and businesses in the Marrickville Local Government Area. The three pages are:

If your queries about stormwater are not answered by these pages, please call Council's Customer Service Centre on 9392 5000, who will provide advice on the problem or refer the issue to an appropriate Council officer.