Leak Detection Adelaide: Find the Hidden Leak Before It Finds Your Slab

Do the meter test first, before you call anyone

This takes half an hour and it tells you whether you have a leak. Do it before spending money on anybody, including us.

1. Turn off every tap inside and out, and stop the washing machine, dishwasher, irrigation controller, pool auto-fill and evaporative air conditioner. A running toilet will show up as a leak, so deal with that first or allow for it.
2. Find the meter, normally at the front boundary, and write down every digit including the small red or black ones. Those are litres, and they are where a slow leak shows.
3. Look for the leak indicator: a small triangle, star or dial that spins on tiny flows. If it is turning with everything off, water is moving right now.
4. Wait 30 minutes and use no water. Longer is better for a slow leak, and overnight is the definitive version of the test.
5. Read the meter again. Any change with nothing running means water is escaping on your side of the meter.
6. Narrow it down. Close the isolating tap on the property side of the meter and watch again. A meter that stops means the leak is beyond that valve, inside the property. A meter that keeps moving means the leak is on the service line under the front yard, path or driveway.

Whose leak is it, yours or SA Water's

This decides who pays, and the boundary is simpler than most people expect. SA Water owns the water main in the street and the meter itself. From the outlet side of that meter onwards the pipework is the property owner's: the service line crossing the front yard, everything under the house, and every fitting inside it.

The same split applies to wastewater. The sewer main is SA Water's and the private drain from the house to the connection point is the owner's, which is why a fault on the private drain is a plumbing job while the identical fault 3 metres further along is a phone call to SA Water. Establishing which side of that line a fault sits on is part of the work.

Strata and unit properties add a layer. Where several dwellings sit behind a single meter, the leak can be on shared infrastructure and the cost sits with the body corporate rather than the resident whose bathroom is wet.

The signs of a concealed leak

Most concealed leaks announce themselves long before the bill does.

• A warm or hot patch on a tiled or concrete floor. That is a hot water line leaking under the slab, and it is the most reliable sign on this list.
• The sound of running water when nothing is on, most obvious at night, or pressure that has dropped across the whole house rather than at a single tap.
• A patch of lawn that stays green through an Adelaide February while everything around it browns off, or ground that is soft and never dries.
• Mould, blistering paint, lifting skirting or a musty smell in a room with no obvious water source.
• Tiles sounding hollow, a crack that keeps moving, or doors sticking on one side of the house only.

The last of those is why an under-slab leak is a structural issue and not just a water bill. Adelaide sits on reactive clay that swells when wet and shrinks when dry, and a footing system is designed around the soil beneath it moving more or less evenly. A leak keeps a single pocket of that clay saturated while the rest of the site dries through summer, and the differential movement that follows is what cracks slabs, jams doors and opens gaps at cornices.

How leaks are actually found

No single instrument finds every leak. The skill is matching the method to the pipe.

A real job chains 2 or 3 of these. Isolation testing proves the leak is on the hot circuit, thermal imaging narrows it to a section of floor, acoustic listening puts a mark on the tile. That sequence is what lets a repair open a single square metre instead of a room.

What leaks in Adelaide homes, and where

Marc has spent 20 years across this housing stock, and what leaks where follows the build era more closely than the suburb.

• Pre-1940s villas and bungalows through Goodwood, Unley, Malvern and Norwood: galvanised steel supply pipe corroding from the inside. Failure is by pinhole, and pinholes arrive in clusters because the whole run is the same age.
• Interwar and 1950s to 1960s homes in Colonel Light Gardens, Cumberland Park, Panorama and Mitcham: first-generation copper at the end of its life, including the under-slab hot water line that presents as a warm floor and is the most expensive leak to ignore.
• Early polyethylene service lines from the 1970s and 1980s: brittle with age, failing at fittings and where they pass under a driveway.
• Coastal suburbs including Glenelg, Hove and Brighton: external fittings and garden taps corroding in salt air, plus a high water table that slows any excavation.
• Hills properties through Blackwood, Belair, Stirling and Aldgate: long private service runs from meter to house, tank and pump plumbing, and ground movement on steep reactive blocks. A leak 60 metres from the house shows nothing near the house.

The pattern that catches people out is the second failure. Once a galvanised or early copper system produces its first pinhole, the rest of that run carries the same age, water and wall thickness. Patching that first leak is correct in the moment, and it is also when the conversation about replacing the run should start.

When it is not a leak at all

Plenty of high water bills are not leaks, and a detection callout on a property with a still meter is money spent for nothing. We would rather say so here than take the booking.

• Evaporative air conditioning. Through an Adelaide summer these use serious volumes, and a stuck float or a badly set bleed turns that into a continuous run to the drain. Bills climb in December and January for this reason alone.
• Irrigation. A solenoid that does not fully close, a controller running 2 programmes it was never meant to, or a sub-surface line cut by a spade. That is real water use, fixed at the controller.
• A pool or water feature topping up, because evaporation over an Adelaide summer is significant and an auto-fill quietly covers it.
• A running toilet, the most common cause of a mysteriously high bill anywhere, and free to check with food colouring in the cistern.
• The billing period itself. A quarter with more days in it, or an estimated read followed by an actual read, both look like a leak and are not.
• A change in the household. Visitors, a new occupant, a new appliance. Unglamorous, and frequently the answer.

What happens on the day

Detection and repair are quoted separately, because until the leak is located nobody can price the repair honestly.

On the day, Marc texts an arrival time before setting off. The visit starts at the meter and the isolation points, because confirming the leak and identifying its circuit comes first. The location is then marked physically on the surface, and you are told what the repair involves and what it will cost before anything is opened up. Rerouting a line is sometimes the better answer than breaking a slab, and where that is the case we say so.

Questions we get asked