Penrith Council Stormwater, OSD & WSUD Requirements Guide

Stormwater Rules for Builders in Penrith

Penrith City is carrying a major share of Western Sydney’s growth. Jordan Springs, Glenmore Park, Orchard Hills, Caddens, Claremont Meadows, St Marys and Emu Plains all have active residential construction, and the arrival of the Western Sydney Airport is accelerating rezoning across the city’s south-east. Penrith Council backs this growth with a clear but demanding set of water controls — and stormwater is consistently among the first technical items its assessment engineers check.

Which Controls Apply

The governing document is the Penrith Development Control Plan 2014 (Penrith DCP 2014). Its water provisions are concentrated in Section C3 – Water Management, which incorporates Council’s earlier Water Sensitive Urban Design Policy and sets out requirements for stormwater quantity, quality and waterway health. Beneath the DCP sit Council’s engineering requirements for development and subdivision, including its stormwater drainage specification for building developments, which govern the technical detail your engineer must meet.

What Penrith Typically Requires for Residential Projects

• On-site detention (OSD): as a minimum, developments must demonstrate no increase in runoff from the site across the full range of storms up to and including the 1% AEP event. Outlets are generally orifice-controlled, and Council distinguishes OSD from rainwater tanks and retention systems — a tank alone will not satisfy the detention requirement. Confirm the current design criteria for your catchment before sizing storage.
• Stormwater drainage plans: a complete drainage design with a lawful point of discharge, pipe and pit layout, levels and overland flow paths is expected with the application for dwellings, dual occupancies and townhouses.
• WSUD and water quality: Section C3 takes an integrated approach to the water cycle. Stormwater quality devices — raingardens, bioretention, tanks — are to be sized using MUSIC modelling with Penrith-specific data per Council’s WSUD technical guidance.
• Easements: where gravity discharge to the street is not possible, an inter-allotment drainage easement is the standard expectation; allow time to negotiate and register it.

Duplexes and Infill

Infill duplexes in established suburbs such as South Penrith, Kingswood and St Marys frequently trigger OSD because of the jump in roof and driveway area. On flat lots with shallow falls, achieving cover over pipes and a workable tank outlet can drive the site layout, so resolve the stormwater concept before locking in the architectural plan.

Local Factors in Penrith

• The Nepean River: the river and its floodplain shape development along the city’s western edge, including Emu Plains and parts of Penrith itself. Flood planning levels and evacuation considerations apply on affected land.
• South Creek and Ropes Creek catchments: much of the eastern LGA drains to South Creek — a catchment under significant cumulative pressure — so water quality and detention performance are scrutinised closely, particularly around Orchard Hills and the airport growth area.
• Clay soils and flat grades: Cumberland Plain clays limit infiltration, and the flat terrain east of the river makes overland flow management and pipe grades a recurring design challenge.

Preparing a Council-Ready Application

Commission a detail survey, confirm your lawful point of discharge and any flood affectation, and brief a civil engineer to prepare the OSD and WSUD package against the current Section C3 criteria and engineering specifications. For projects in release areas like Orchard Hills, check the status of trunk drainage delivery — your discharge point must actually exist. A coordinated stormwater package at lodgement is the most reliable way to avoid an extended assessment.

Contrive Consultants prepares stormwater, OSD and WSUD designs accepted by Penrith City Council, from single dwellings to multi-unit and subdivision work. Review our services or contact our team — call +61 497 848 111 or email info@contriveconsultants.com.au.