Why does the outdoor gully at our Scarborough unit keep filling with sand?

Close to the beach, sand blows and washes in through grates and around pavers, then settles where the drain is flattest. We flush it out with the hydro jetter and check the grate. If the gully is overflowing with dirty water rather than sand, that points to a sewer blockage, so call.

Drains are backing up in several units in our apartment block. Who should we call?

Tell the strata manager first, because a shared stack or drain is usually common property. We take bookings from strata managers and will be clear about which part is your lot and which part is shared.

We’ve bought an older Doubleview house. Should we check the drains before renovating?

If the drains are slow or the overflow relief gully has ever overflowed, a CCTV drain camera inspection shows roots, cracks or dips in the old line, so you can plan for it before the new bathroom goes in.

Do you do hydro jetting and drain camera inspections in Karrinyup and Carine?

Yes. We use the hydro jetter for roots, grease and sand, and a CCTV drain camera to find out why a drain keeps blocking and how far along the line the problem is.

Who pays if the blockage is in the sewer main?

Blockages in your property plumbing are the owner’s responsibility. If it’s in Water Corporation’s main, normally outside the property, Water Corporation clears it. If we find it there, we call them in.

North-west coast · Blocked drains, Scarborough to Watermans Bay

Blocked drains in Scarborough, Karrinyup, Doubleview and Innaloo

In 1898 a land company cut up the ground around Njookenbooroo Swamp for market gardens and dug channels to drain it into Herdsman Lake. Today that swamp is Innaloo. Gwelup’s newer streets went in during the late 1990s, after more swamps were drained, while Carine kept its two swamps as a wetland reserve and built around them. Between those old wetlands and the beach you’ll find wartime timber-frame houses, 1970s brick and tile, beachside apartments and new builds on old blocks, and their drains are every bit as mixed.

The short answer

McDermott Plumbing clears blocked drains, toilets and sinks in Scarborough, Trigg, Doubleview, Innaloo, Woodlands, Churchlands, Karrinyup, Carine, Gwelup, Hamersley, North Beach and Watermans Bay. Call (08) 6187 3999 or text 0406 882 648. It’s a run across to the coast from our Ellenbrook base, so we’ll give you a real arrival time when you ring. We clear with a drain machine or the hydro jetter, and use a CCTV drain camera to see why a line keeps blocking. If sewage is overflowing from Water Corporation’s main or onto the street, call Water Corporation on 13 13 75 as well.

Scarborough and Trigg: apartments and beach sand

Scarborough Beach is the restaurant, bar and nightclub strip, and the 24-level hotel built as Observation City has stood over it since 1986. The City of Stirling has since capped new buildings there at eight storeys, so the streets behind the beach now mix mid-rise apartments, older blocks of flats and houses. In a block of units, several homes drain into one stack and one line, and Water Corporation says a single 100 mm junction can serve up to five home units. When one kitchen or toilet chokes that line, the unit lowest down usually finds out first.

The other coastal problem is sand. It blows and washes into courtyard floor wastes, outdoor gullies and grated drains near the beach, then settles wherever the fall is flattest. Trigg, which only started to develop in the late 1940s, gets the same thing in its streets closest to the dunes.

Doubleview, Innaloo, Woodlands and Churchlands

Doubleview’s first subdivisions went on sale in 1910 and again in 1916 and 1926, and mostly failed to sell. Shortly after the Second World War, the State built timber-frame homes for returning soldiers in its northern streets. Innaloo’s southern subdivision was approved in 1916, yet only ten houses stood there by the 1920s. Building took off during the war, and the suburb was essentially finished by 1970. Woodlands Primary opened in 1964 with 53 students and peaked at 609 in 1975, which tells you how fast that suburb filled. Churchlands is newer, with most homes built after the 1980s.

Water Corporation says homes more than 15 years old are less likely to have PVC sewer pipe, and that a hairline crack is enough for a root to get in. Most original house drains between Scarborough Beach Road and Jackadder Lake are decades past that. Where an old house has been knocked down, the new home gets new PVC drains, but they usually still run to the sewer junction the old house used. On renovations, new pipe is often tied into the original line, and that joint is worth checking if a drain keeps blocking.

Karrinyup, Carine, Gwelup, Hamersley, North Beach and Watermans Bay

North Beach and Watermans Bay filled up quickly after the war, and by 1961 nearly all of both suburbs had been built. Star Swamp Bushland Reserve, set aside as a 96-hectare A-class reserve in 1987, covers about half of the two suburbs’ land. Hamersley was laid out from 1968 as one of Perth’s first cul-de-sac suburbs, under a development scheme that planned water supply, sewerage and drainage from the start, and it was finished in 1981. Carine was built in stages from the early 1970s to 1987, and its two swamps are now Carine Regional Open Space.

Karrinyup’s growth began in 1957, south of Karrinyup Road first. Gwelup was mostly market gardens until it turned residential from the 1970s, and a few gardens still remain along North Beach Road. Its newest streets went in during the late 1990s, when the swamps were drained. So a Karrinyup or Carine house drain may be 40 to 60 years old, while a Gwelup one could be under 30. The older ones sit under gardens that have had decades to grow.

What blocks drains around Scarborough and Karrinyup

Beach sand in outdoor gullies, grated drains and courtyard floor wastes near the coast.
Shared stacks and lines in apartments and older blocks of flats, where one unit’s blockage backs up into the next.
Tree roots in older house drains under established gardens in Doubleview, Woodlands, Carine and Karrinyup.
Joints where a rebuild or renovation tied new PVC into an older line.
Fat and wipes. Water Corporation says fats, oils and grease hardening in pipes cause 30% of its wastewater blockages, and that wipes don’t break down like toilet paper, even if the packet says flushable.

Blocked sink in Scarborough?

In a Scarborough apartment, a slow kitchen sink can be your own trap or the shared stack. If the neighbours’ sinks are slow too, let the strata manager know and tell us when you ring. In an unrenovated 1960s or ’70s Karrinyup or Carine kitchen, grease and scraps build up in the trap and the short waste under the bench, and a dishwasher teed into the same waste adds to it. Try the safe checks in our blocked kitchen sink guide first, and leave the caustic drain cleaner on the shelf. If the toilet, shower or outdoor gully backs up as well, the blockage is further down the drain. Stop using water and call.

How we clear it

We clear from the inspection shaft, gully or nearest sensible access point. Sand and grease get the hydro jetter, which flushes the line clean rather than just poking a hole through the blockage. Roots get cut back with the jetter or a drain machine. When a drain keeps blocking, the CCTV drain camera shows what’s in the pipe and where, whether that’s a root at an old joint or a dip where sand collects. Jetting won’t mend a cracked or sunken pipe, and if that’s what we see, we’ll say so.

If the blockage turns out to be in Water Corporation’s main, normally outside the property, it’s theirs to clear and we report it. Blockages within the property plumbing are the owner’s responsibility.

Suburbs we cover here: Scarborough, Trigg, Doubleview, Innaloo, Woodlands, Churchlands, Karrinyup, Carine, Gwelup, Hamersley, North Beach and Watermans Bay.

Common questions

Why does the outdoor gully at our Scarborough unit keep filling with sand?: Close to the beach, sand blows and washes in through grates and around pavers, then settles where the drain is flattest. We flush it out with the hydro jetter and check the grate. If the gully is overflowing with dirty water rather than sand, that points to a sewer blockage, so call.
Drains are backing up in several units in our apartment block. Who should we call?: Tell the strata manager first, because a shared stack or drain is usually common property. We take bookings from strata managers and will be clear about which part is your lot and which part is shared.
We’ve bought an older Doubleview house. Should we check the drains before renovating?: If the drains are slow or the overflow relief gully has ever overflowed, a CCTV drain camera inspection shows roots, cracks or dips in the old line, so you can plan for it before the new bathroom goes in.
Do you do hydro jetting and drain camera inspections in Karrinyup and Carine?: Yes. We use the hydro jetter for roots, grease and sand, and a CCTV drain camera to find out why a drain keeps blocking and how far along the line the problem is.
Who pays if the blockage is in the sewer main?: Blockages in your property plumbing are the owner’s responsibility. If it’s in Water Corporation’s main, normally outside the property, Water Corporation clears it. If we find it there, we call them in.

Nearby

Blocked drain and plumber pages for the areas next to this one.

How we clear drains here.

Official sources

Last updated 16 October 2026. General information only. Every property is different, so call us to talk about yours.

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