North Shore facts, by council
Apartments near the harbour
At the 2021 Census, flats or apartments were 75.7% of occupied homes in North Sydney's council area, 56.7% in Lane Cove's, 52.0% in Mosman's and 47.1% in Willoughby's. In North Sydney, 51.9% were rented.
Houses further north
Separate houses made up 68.6% of occupied homes in Ku-ring-gai's council area and 69.5% in Hornsby's. Only 19.8% of Ku-ring-gai's homes were rented.
Easements in North Sydney
North Sydney Council's planning rules say inter-allotment stormwater drains through private land remain the owners' responsibility for good, unless the title deeds make Council responsible.
Wastewater Fix suburbs
Sydney Water's update of 2 February 2026 lists Artarmon, Chatswood, Crows Nest, Naremburn, Neutral Bay, North Sydney, Northbridge and St Leonards for work over the following 12 months.
Mosman's stormwater rules
Mosman Council's stormwater policy, adopted on 3 December 2024, puts upkeep on the owner: roof gutters, downpipes, pits and drainage pipes, all the way to the point of connection with Council's system. Council can require that maintenance under the Local Government Act 1993 and the Roads Act 1993.
Blocks that fall away from the street face strict limits. Council will not approve pumps for surface stormwater under any circumstances, and treats absorption trenches as inadequate as the main drainage in most of Mosman. A charged pipe, which uses the height of the roof to lift roof water up to the street gutter, needs at least 1.5 m of head, a fully sealed pipe and a cleaning eye at the lowest point.
Strata, smoke tests and the sewer
With so many apartments in the harbourside councils, strata rules settle most leak disputes. In NSW the lot owner usually covers pipes inside internal walls and fixtures, and the owners corporation covers pipes in boundary walls and under the floor.
Wastewater Fix is Sydney Water's search for rainwater leaking into the sewer. Affected households get a letterbox notice, checks can include smoke testing private pipes, and services keep running throughout.
On a house block, the private wastewater line is the owner's up to and including where it joins Sydney Water's system, which can be past the boundary. If a plumber finds a blockage in Sydney Water's pipe and reports it there and then, you can claim reasonable costs for up to 2 hours of their work.
What we would do
Start with your council, because that's what changes the job here. In North Sydney, check your title for drainage easements before a plumber works on a shared line. On a Mosman block that falls away from the street, ask for a drainage design that fits Council's policy before anything is dug. We'll match you with a drainage specialist for your suburb.