Hillarys, by the numbers and the rules
Mostly owner-occupied houses
In the suburb of Hillarys, 89.4% of occupied homes were separate houses at the 2021 Census. 44.8% were owned outright, and only 13.5% were rented.
Runoff stays inside the boundary
The City of Joondalup requires owners to keep roof, paving and pool water within their lot. It asks for one downpipe for about every 15 square metres of roof, spaced no more than 12 metres apart.
Your neighbour's roots
You may dig up a neighbour's tree root and remove it up to your boundary, but not beyond it without their agreement. Street trees belong to the City, and it won't remove one over perceived damage to infrastructure.
A rescue in 2024
On 25 June 2024 a man was pulled from a 3-metre-deep hole in Hillarys after an unapproved dig to reach a sewer main collapsed. Water Corporation says approval is legally required for work within set distances of its pipes.
Soakwells that don't undermine anything
As a guide, Joondalup wants a soakwell set back from buildings and boundaries by at least its own width. The point is that the hole dug for it shouldn't undermine fences, retaining walls or footings. Narrow side passages are a poor spot for one, because there isn't enough soil around it to drain into.
When a soakwell does overflow, the system has to steer that water away so it doesn't pond against the house or run onto the neighbour's block. A plumber who specialises in stormwater can size the soakwells to the roof and paved area.
Before anyone digs near the sewer
After the Hillarys rescue, Water Corporation's advice was to use a licensed plumber or builder for any work near its assets and to check Before You Dig Australia for hidden services first. Those plans mark the water mains, sewer mains and sewer junctions at a property.
Inside your boundary, the sewer line up to the junction with the main is the owner's to keep clear. If your plumber traces a blockage into the main, Water Corporation's crew takes over and pays the plumber a standard fee for finding it. Read more on tree roots in drains, pipe relining in Perth and stormwater.
What we would do
If roots from next door are in your drain, a plumber can cut them back on your side of the boundary, but let your neighbour know first, as the City suggests. Never open a manhole or dig toward a sewer main yourself. Ask a drain specialist to locate the line and, if the work comes close to Water Corporation's pipe, to get its approval before a shovel goes in.