Canterbury-Bankstown Stormwater & OSD Requirements Guide

Stormwater Rules for Builders in Canterbury-Bankstown

The City of Canterbury Bankstown is Sydney’s most populous council and a heavyweight infill market. Bankstown, Campsie, Canterbury, Lakemba, Belmore, Greenacre, Revesby and Padstow all carry strong duplex, townhouse and apartment activity, with major intensification planned around the Bankstown and Campsie centres on the new metro line. Nearly every project here is redevelopment of established land draining to older infrastructure – so stormwater and on-site detention (OSD) are front and centre in Council’s assessment.

The Planning Controls That Apply

The governing document is the Canterbury-Bankstown Development Control Plan 2023 (CBDCP 2023) – the consolidated plan that replaced the separate former Bankstown and Canterbury DCPs and now provides one set of controls across the merged LGA. It contains Council’s requirements for stormwater management and drainage alongside chapters addressing development on flood prone land. Council’s engineering and stormwater technical requirements sit beneath the DCP and govern the detail of drainage and OSD design, and Council offers a stormwater information service for confirming drainage assets and discharge arrangements for a site.

What Council Typically Requires for Residential Projects

• On-site detention (OSD): dual occupancies, multi-dwelling housing and other development that increases impervious area generally require OSD with controlled discharge to Council’s system. Permissible discharge rates and storage volumes are set by Council’s current technical requirements and vary with catchment – confirm them before sizing, and don’t reuse figures from pre-amalgamation approvals.
• Stormwater drainage plans: a civil engineer’s design showing the lawful point of discharge, pipe and pit layout, levels and overland flow paths is expected with the DA or CDC.
• Flood prone land controls: the DCP contains specific objectives and standards for flood-affected land, including floor levels and flood-compatible design where mapping applies.
• WSUD and rainwater reuse: larger projects attract water quality treatment requirements, and rainwater tanks are commonly integrated with BASIX commitments on dwellings and duplexes.
• Easements: low-side lots that cannot drain by gravity to the street need inter-allotment drainage easements – a frequent issue in the undulating streets around Revesby, Padstow and East Hills.

Duplexes and Townhouses: Where Applications Stall

The most common stormwater problems in this LGA are familiar infill ones: flat lots in Campsie, Lakemba and Greenacre with minimal fall to the kerb; rear dwellings on battle-axe arrangements without a gravity outlet; and OSD tanks squeezed by deep soil and landscaping requirements. Each is solvable, but only if the drainage concept is settled before the architectural layout is finalised.

Local Factors in Canterbury-Bankstown

• Two river catchments: the LGA straddles the Cooks River catchment in the north-east – one of Australia’s most urbanised waterways, draining Campsie, Canterbury and Belmore – and the Georges River catchment to the south and west, taking flows from Bankstown, Revesby and Padstow via tributaries such as Salt Pan Creek and Little Salt Pan Creek.
• Overland flow: decades of intensification have left mapped overland flow paths through many residential streets; affected lots carry floor level and flow path protection requirements.
• Clay soils: as across most of the Cumberland Plain, tight clays make infiltration unreliable as a primary disposal method.

How Builders Should Prepare

Request Council’s stormwater information for the site early, order a detail survey, and check flood and overland flow mapping during due diligence. Have a civil engineer confirm the lawful point of discharge and prepare the OSD and drainage package to Council’s current requirements before lodgement. With the volume of applications moving through this council, complete and compliant stormwater documentation is the difference between a smooth assessment and months of back-and-forth.

Contrive Consultants prepares stormwater and OSD designs accepted by Canterbury-Bankstown Council, from duplexes to multi-unit developments. View our services or contact us – call +61 497 848 111 or email info@contriveconsultants.com.au.