Civil & Stormwater Engineers Kellyville NSW

Kellyville is where The Hills Shire’s growth story began, and it’s now entering its second act. The suburb was semi-rural for most of the twentieth century — apart from the older pocket of homes around Acres Road known locally as “The Village” — until a late-1980s policy shift opened Sydney’s north west to suburban development. The waves of housing built through the 1990s and 2000s are now twenty to thirty years old, and Kellyville has become one of the region’s busiest markets for knockdown-rebuilds, duplexes and granny flats. Contrive Consultants, based one suburb north in Rouse Hill, provides the civil and stormwater engineering that this kind of infill work depends on.

Building in Kellyville

Kellyville sits about 36 kilometres north-west of the Sydney CBD within The Hills Shire. Its transport story has steadily strengthened the case for redevelopment: the North-West T-way bus corridor opened in 2007, and Kellyville Station on the Sydney Metro Northwest line opened in May 2019, putting much of the suburb within reach of a fast rail connection. Around the station and along the Old Windsor Road corridor, planning has shifted toward higher densities, while the traditional streets between Windsor Road and Samantha Riley Drive remain family-home territory — increasingly rebuilt one lot at a time.

For engineers, established Kellyville is a different animal from the greenfield precincts nearby. Lots here come with history: existing drainage easements from 1990s subdivisions, ageing interallotment pipes, mature street trees over council drainage lines, and neighbours whose properties have relied on established overland flow patterns for decades. Redevelopment has to work with that inheritance. The suburb’s catchments fall generally toward the creek systems feeding Cattai Creek to the north and the Parramatta River tributaries to the south, and The Hills Shire applies its stormwater and OSD standards firmly across all of it.

What builders need in Kellyville

Typical engineering requirements for Kellyville projects include:

Stormwater drainage plans for knockdown-rebuilds, additions, granny flats and duplexes — designed to the lot’s legal point of discharge, which on older lots is not always where owners assume.
On-site detention (OSD) — The Hills Shire generally requires OSD for new multi-dwelling development and subdivision; for straightforward like-for-like rebuilds the requirement can differ, so it pays to confirm rather than assume. Council also holds strong preferences on OSD tank construction and configuration.
Easement due diligence — checking the 88B instrument and physical location of existing drainage easements before design, since building over or near them requires specific approvals.
Charged and pump systems where rear-of-lot granny flats can’t reach the street by gravity.
Driveway and vehicular crossing design to council specification, especially where levels changed with the rebuild.
Erosion and sediment control, waste management plans and BASIX certificates as standard application companions.

Duplex projects deserve their own note: Kellyville’s wider 1990s lots make attractive duplex sites, but the stormwater strategy — OSD location, easement position, driveway falls — frequently determines whether the floor plan works. Engineering input at concept stage protects the feasibility.

Our services in Kellyville

One local group, every consultant a Kellyville redevelopment needs:

Civil and stormwater engineering (Contrive) — drainage plans, OSD design, easement assessments and certifier liaison from DA through to occupation certificate.
Architecture, landscape and visualisation (ARQI) — knockdown-rebuild and duplex designs shaped around the site’s real constraints.
Town planning (URBA) — Hills DCP compliance advice, dual occupancy strategy and DA management.
Surveying (partner company) — detail surveys picking up existing structures, services and easements accurately.
NatHERS and BASIX (NathersPRO) — certificates for rebuilds, additions and secondary dwellings.
Swept path analysis (Sweptpaths) — vehicle access checks for duplex driveways, tight garages and corner lots.
Waste management plans (Contrive) — demolition and construction waste documentation, essential for knockdown-rebuilds.
NBN pit and pipe (Pit and Pipe) — servicing design where subdivision creates new lots.

Kellyville redevelopment FAQs

Do I need OSD for a knockdown-rebuild in Kellyville?

Not always — a single dwelling replacing a single dwelling is treated differently from subdivision or multi-dwelling development under Hills Shire policy, and the answer depends on your site’s circumstances and catchment. We check your property against council’s current requirements and give you a definitive answer before design starts.

There’s an old drainage easement across my Kellyville backyard. Can my granny flat go over it?

Generally structures must keep clear of drainage easements, though minor encroachments can sometimes be negotiated with engineering justification. The first step is confirming the easement’s exact position and contents — surveys and 88B instruments from the 1990s don’t always match what’s in the ground. We investigate and design around the constraint.

My duplex DA got a stormwater RFI from The Hills Shire. Can you take it over?

Yes, we regularly pick up projects mid-application. We review council’s comments, amend or redesign the drainage and OSD to the current specification, and deal directly with council’s development engineers until the condition is cleared.

Rebuild Kellyville with local engineers

From a granny flat drainage plan to a full duplex consultant package, we’ve got Kellyville covered from ten minutes up the road. Call +61 497 848 111, email info@contriveconsultants.com.au, see the full services list, or get a quote via our contact page.