Seven Hills at a glance
A suburb of houses
At the 2021 Census, 84.1% of occupied homes in the suburb were separate houses, 9.9% townhouses or semis and 5.6% flats. 35.3% were rented and 27.5% owned outright.
Blacktown City Council
Blacktown City lists Seven Hills (2147) as one of its suburbs, and every dwelling ABS counts in the suburb falls in its area. Council handles street drainage and stormwater complaints.
On Sydney Water's 2026 list
A Wastewater Fix update dated 2 February 2026 names Seven Hills among suburbs where Sydney Water's contractor will work over the following 12 months, finding where stormwater gets in.
When Council steps in
Blacktown City may act when water comes from faulty roof drainage on a house, garage, shed or carport, or is concentrated by a structure or drain. Natural run-off from higher land is usually not its job.
What Wastewater Fix looks for
Rain that gets into the sewer can overload it and push wastewater onto properties, sometimes inside homes. Sydney Water's crews do visual checks and smoke testing, including the private stormwater and wastewater pipes that connect to its system. People directly affected get a letter in the letterbox first.
On private land, the usual culprits are a downpipe plumbed into a wastewater pipe or an overflow relief gully, a cracked or badly sealed sewer pipe that lets groundwater in, and a gully that is damaged or sits too close to the ground. Sydney Water says rainwater and stormwater must not enter your wastewater system. Re-routing a downpipe or raising a gully is work for a licensed plumber, and our guide to the overflow relief gully shows what it does.
Run-off from a neighbour's yard
If water floods in from next door, Blacktown City wants to know what happens, when, and how often, plus photos taken while it's happening and any professional advice you've had. It also asks whether you've spoken to the neighbour or tried mediation.
Council may decline to act if the water is natural run-off, crosses driveways or paving, happens only in exceptionally heavy rain, or comes from a blocked private inter-allotment easement. Where a sloping block was cut flat, Council suggests sub-surface drains such as agricultural pipe to catch seepage.
Where your sewer ends
Sydney Water owns the junction on its main. The pipes from your house up to and including the point of connection are yours, even where they run past the boundary. If a licensed plumber finds the blockage is in Sydney Water's pipe and reports it, you can claim reasonable costs for up to 2 hours of work. More on blocked drains in Sydney.
What we would do
Walk around the house in the next downpour. Watch where each downpipe goes and whether water bubbles up from the gully near the outside tap. If a downpipe disappears into the sewer side, or the gully grate sits level with the lawn, have a drainage plumber fix it now, before a smoke test or an overflow finds it for you.