This is a concept website · Enquire about this domain

Water on a North Shore block, a guide by Dotto

Plumbing and drainage on Sydney’s North Shore, New South Wales

The six guides

Guide · Stormwater

Stormwater on a sloping block

Rain and sewage leave a block by two separate systems: stormwater runs through pipes into creeks, rivers and the harbour without treatment, while sewage goes to the sewer. On a slope, when rain from a block cannot reach the street without crossing lower land, North Sydney Council’s planning rules for development call for a drainage easement through the neighbouring property.

Plan of two lots on a slope, contour lines running across them. Roof water from the house on the upper lot runs in a pipe into a strip along the side of the lower lot, the easement, and down it to the kerb and gutter in the street. A dashed arrow inside the easement marks the emergency overflow path. House3UPPER LOT1 House3LOWER LOT2 STREET9 KERB AND GUTTER8 DOWNPIPE4 EASEMENT6 PIPE5 OVERFLOW PATH7 DOWNHILL10
  1. 1Upper lot
  2. 2Lower lot
  3. 3House on each lot
  4. 4Downpipe
  5. 5Stormwater pipe
  6. 6Easement along the side of the lower lot
  7. 7Emergency overflow path, inside the easement
  8. 8Kerb and gutter
  9. 9Street
  10. 10Downhill
Drawn for this guide, seen from above: roof water from the upper lot reaching the street through an easement along the side of the lot below, with an emergency overflow path inside it. Not to scale, and not any real street.

Two systems, side by side

From the NSW EPA, North Sydney Council and Building Commission NSW.
StormwaterSewage
What it carriesRain that falls on streets and does not soak into the ground.Sewage and other permitted discharges, collected by sanitary plumbing.
Where it goesThrough pipes into local rivers and creeks; in North Sydney, from the street and gutter into the harbour.Through a sanitary drain to a sewer.
Treated?No. North Sydney Council says larger items are caught in physical traps, but the water is not treated.North Sydney Council contrasts it with stormwater: “unlike sewage, stormwater is not treated.”
Licensed workGutters and downpipes are roof plumbing, a licence category of its own.Sanitary plumbing and draining, each a licence category.

The EPA’s stormwater guidance for businesses is titled “the drain is just for rain”, and it notes that it is against the law to place any material where it could flow into a local waterway and cause pollution. North Sydney Council’s planning rules make the same point for new drains: they should be designed to accept rainwater only.

Sydney Water’s customer contract draws the line from the other side: a property owner must not allow rainwater to enter their wastewater system, though rainwater can still be used to save drinking water, such as for flushing toilets (clause 8.5(3)).

When the slope runs through a neighbour

North Sydney Council’s Development Control Plan 2013 has a section on stormwater management. It applies to development applications that add hard surfaces to a site or change how the site drains. Its rules for a block that drains downhill through other land include:

  • No nuisance downhill. Stormwater from private property should not cause drainage problems for any other property. The plan defines nuisance drainage as any damage to other property from stormwater caused by development.
  • An easement when there is no direct path. Where a block’s stormwater can only reach a road by passing through a neighbour’s land, an inter-allotment drainage easement is required. The plan says it should be sought by negotiation, by mediation, or under section 88 of the Conveyancing Act 1919.
  • Room for machinery. Easement widths are governed by what is needed to reach and maintain the pipes with machinery.
  • A way out for heavy rain. Systems through adjoining property should allow for an emergency overflow path inside the easement, and nothing should be placed in an easement or overflow path that could block surface run-off.
  • Stay in your catchment. Water should stay in its own catchment; sending it into the next one is acceptable only where it is shown that no property or structure will be harmed.
Pipe sizes in the plan

As at October 2026, the plan sets a minimum of 100 mm internal diameter, sewer grade, for pipes from downpipes to a primary inter-allotment drain, and 150 mm for the primary inter-allotment drain itself.

Who looks after the pipe

The plan is direct about this. Inter-allotment stormwater drains, which carry one block’s water through a neighbour’s land, “remain forever the responsibility” of the property owner, including easements, unless the title deeds name the council as responsible for maintaining the easement. Where new drainage from a development is built to a public road and is to revert to the council’s ownership, the developer pays for it.

Owners of properties affected by a stormwater easement are required, among other things, to let stormwater drain through the system, keep it clean and free of silt and rubbish, maintain and repair it, and make no alterations without the council’s written consent.

At the street

Most development has to connect its drainage to the council’s gutter or stormwater pipe in the road alongside, which usually means digging in the footpath or roadway. The plan lists a Street Opening Permit, a Construction Certificate and approved design plans before construction starts, and separate approvals under section 138 of the Roads Act 1993 and section 68 of the Local Government Act 1993 for work in a public road or footpath.

One North Shore detail: North Sydney has many stretches of kerb with heritage and conservation significance. Heritage sandstone kerb and gutter stays in place rather than being swapped for concrete, and heritage kerb disturbed by drainage work must be rebuilt at no cost to the council.

Slowing the water down

The plan asks new drainage to fit the natural system as far as possible: detain stormwater on site, keep paved surfaces to a minimum, store water for reuse such as in rainwater tanks, and keep existing trees. It prefers on-site detention on unpaved or grassed surfaces, to trap contaminants and let more water soak into the ground.

These are North Sydney Council’s rules, taken from its own plan. If your block is in another council area, look for the stormwater section of that council’s development control plan.

North Sydney Council

(02) 9936 8100Customer Service Centre, 9am to 5pm. The council takes reports of water pollution for investigation.

More from the sheet