Why does Council open Narrabeen Lagoon?

To let floodwater drain to the sea. Council opens the entrance mechanically when the lagoon reaches 1.0-1.3m AHD, but warns that opening it may not stop flooding in very heavy rain or strong swell.

Sewage is coming up in the street during a flood. Who do I call?

Sydney Water, on its 24/7 faults line. Sydney Water's guide says an overflow from public land during widespread flooding is probably in its pipes. Keep clear of the water.

Plumbers in Narrabeen: lagoon flooding, gullies and unit blocks

Plumbers in Narrabeen Life beside the lagoon.

Narrabeen sits on Narrabeen Lagoon, which floods when heavy rain or ocean storm surge raises it faster than water can escape to the sea. Most homes are units, Northern Beaches Council handles flooding and drainage, and Sydney Water runs the sewer. Tell us the job and we'll match you with a licence-checked local plumber who specialises in drains and wet-weather faults.

Narrabeen facts for a plumbing job

Mostly units

At the 2021 Census, 64.7% of the suburb's occupied homes were flats or apartments, 18.7% townhouses or semis and 15.8% separate houses. 37.5% were rented.

A lagoon that closes

Narrabeen Lagoon is one of four ICOLLs on the Northern Beaches, lagoons whose entrance opens and shuts with sand and rain. It stayed shut for four years in the 1924-1928 drought.

Opened by machine

Council mechanically opens the entrance once the lagoon reaches 1.0-1.3m AHD. It warns that in very heavy rain or strong swell, opening it may not prevent flooding.

Northern Beaches Council

The whole suburb is in the Northern Beaches council area. Council's Flood Hazard Map shows flood prone land when you enter an address.

When the lagoon rises

Lagoon flooding comes from runoff after heavy rain, ocean storm surge, or both. Water spills onto the low-lying floodplain and only drops once it can escape through the entrance. Council, Manly Hydraulics Laboratory and the NSW Government run a flood warning webpage, and Council's planning rules set floor levels above known flood levels.

Rising water tests the plumbing too. Sydney Water says stormwater that gets into wastewater pipes overloads them and causes overflows. One way in is a damaged or low-lying overflow relief gully; another is a downpipe wrongly connected to the sewer.

Whose blockage is it?

Sydney Water's rule of thumb: if sewage overflows during widespread local flooding, or the neighbours have the same trouble, the fault is probably in its pipes. Report it on its 24/7 faults line and stay away from the overflow. If only your place is affected, and only when you run water, look at your private pipes.

Private pipes are the owners' up to and including the point of connection with Sydney Water's system. In a unit block, NSW strata rules usually make the owners corporation responsible for pipes in boundary walls and under the floor.

What we would do

In a ground-floor unit or a low house near the lagoon, ask a drainer to check the gully height and every downpipe connection before the next big rain. In a strata block, ask the strata manager when the building's gullies were last looked at. Both are small jobs next to a sewage clean-up. We'll match you with a drain specialist who handles wet-weather overflows.