Blocked Drains Collaroy

This suburb takes its name from a steamer that ran aground on the beach here in 1881, and the long surf beach it left its name to still shapes how the place was built.

Most development came after the mid-20th century, and it split in two directions from there.

Down near the water, a strip of beachfront units and apartments went up along the Pittwater Road frontage, some of them rebuilt more recently after storm damage to the original buildings.

Further back, on the rising ground toward the plateau above, post-war brick and fibro homes climbed the slope on standard suburban blocks, the kind of stock this network sees all over the northern beaches.

That split matters for drains because the two halves fail differently.

Beachfront properties sit in constant salt spray, and salt air corrodes exposed pipework and fittings faster than it would a few streets inland.

Up on the rise toward the plateau, it's gravity that causes the trouble instead.

Drainage relies on graded falls to move waste and stormwater down toward the beach, and those falls can underperform once a heavy storm arrives, silting up at any point where the slope flattens out.

Add sand blown in off the dunes that works its way into gullies near the foreshore, and there are three separate failure modes depending on where the call comes from.

We run a camera the length of the line before quoting anything, because a plateau block and a beachfront unit rarely need the same fix.

A corroded or collapsed section needs blocked drain repair; sand and silt without structural damage is drain cleaning instead.

Two more issues round out what we see here regularly.

Stormwater overload is the first, tied to the suburb's position near the Narrabeen Lagoon catchment and its low beachfront strip, both of which get tested hard in big coastal rain.

The 2016 east-coast storms that stripped sand off this beach and forced evacuations are the extreme version, but the same low ground surcharges on a smaller scale every serious downpour, and that's when the beachfront drains back up.

Tree roots are the second, working into ageing joints on the older residential slopes the way established gardens always do given enough decades.

Both link back to blocked stormwater, which handles the graded-fall failures either the slope or the lagoon catchment can cause.

A beachfront unit and a plateau-slope house need different handling, and that's not something we work out on the day.

The drive down the coast from Narraweena, our home turf, is a regular one for this crew, which is exactly why the difference isn't a guessing game by the time we arrive.

Fast arrival and a flat $0 call-out apply equally on the seafront and further up the hill.