Baulkham Hills: the local picture
Houses with mortgages
At the 2021 Census, 75.4% of occupied homes in the suburb were separate houses, 13.3% townhouses or semis and 11.3% flats. 43.0% were owned with a mortgage and 22.3% rented.
Not all in one council
The Hills Shire Council lists Baulkham Hills as only partly within its area, and realigned the suburb's boundaries in 2018 when Norwest was created. Your rates notice names your council.
Sydney Water crews in 2026
A Wastewater Fix update of 2 February 2026 lists Baulkham Hills for work over the next 12 months, tracking stormwater that gets into the sewer. Directly affected owners get a letterbox notice.
Consent close to a trunk
Under The Hills Shire's rules for private land, substantially changing the soil level within 3 metres of a tree's trunk needs consent.
Before anyone digs near a tree
Replacing a sewer or stormwater line usually means a trench, and trenches cross root zones. The Hills Shire Council needs consent to prune a tree by more than 10%, to remove any tree that isn't exempt from its Tree Preservation Order, or to substantially alter the soil level within 3 metres of the trunk. Fruit trees and priority weeds are exempt.
So if the only way to a broken pipe runs beside a large tree, check with Council first. It's also worth asking the plumber whether pipe relining could reach the damage without a trench.
How roots get into the sewer
Sydney Water says roots find their way in through small cracks, and suggests not planting trees within 6 metres of wastewater pipes. Its list of trees to avoid near them includes jacarandas, figs, liquidambars, lilly pillies, brush box and camphor laurel.
The junction on Sydney Water's main is Sydney Water's. Even so, roots that push into it at the point of connection are the property owner's to clear.
More Sydney pages
For a line that's already blocked, see blocked drains in Sydney and our guide to tree roots in drains.
What we'd do first
Get a camera inspection before you agree to dig up a root-blocked line near a big tree. Knowing exactly where the break is decides whether you need Council consent at all, and sometimes whether you need a trench. If one is needed within 3 metres of a trunk, sort out the consent before the excavator arrives. We can match you with a drain specialist who works with roots and relining.