Finding a water leak under a driveway without lifting it
A water leak under a driveway can be traced from the surface, so nobody needs to lift the drive to look for it. First we check whether the buried supply pipe is losing water. Then we listen along its line through the tarmac or paving with a ground microphone, or put tracer gas into it. When a second test points to the same place, the spot is marked and photographed, and that is where digging should start.
On many homes, the pipe that carries water from the meter at your boundary into the house runs under the drive. That pipe is usually the owner's. On newer homes it tends to be blue plastic, while older ones may have copper, lead or iron, and often nobody knows exactly where it runs. On farms and homes down a track in Norfolk, Suffolk and the Fens, the meter may be out by the road, with the pipe crossing a yard or paddock first.
Before you ring, pace out the distance from the meter lid to where the pipe comes up indoors, often under the kitchen sink, and note what covers the ground between: tarmac, block paving, concrete, gravel or lawn. Both details help us choose the tests and price the visit properly before you book.
Signs of a leak under a drive
A leak under a hard surface rarely shows itself where it starts. Water takes the easiest route through the ground, often along the loose fill the pipe was laid in, and comes up wherever it can. So the wet patch or sunken block you spot may be some way from the actual hole in the pipe.
Your water meter gives the clearest answer. Turn off every tap, check nothing is filling, such as a toilet cistern or the washing machine, then read the meter and leave it for at least half an hour. If the numbers have moved, water is escaping. If your meter sits at the boundary, close the stop tap indoors and watch again: if it is still moving, the leak is on the pipe outside. Other signs to look for:
A strip of lawn beside the drive that stays greener or squelches
A dark patch on the drive that stays wet after the rest has dried
Water seeping up between blocks, or a joint that never dries out
Blocks that have sunk, rock underfoot or dip in one place
Weaker flow at the kitchen tap than you used to have
A letter from your water company saying readings show constant use
Why digging on a guess costs more
The wet patch is the obvious place to dig, and it is often the wrong one. Because water travels before it surfaces, a hole under the damp can uncover a perfectly dry pipe. Every opening in tarmac or concrete leaves a patch to make good, and each new guess adds another.
Guessing also ignores what else is down there. Gas pipes, electricity cables, phone lines and drainage pipes often cross the front of a property too. Pinning the leak down before anyone breaks the surface gives the dig one place to start, and means fewer holes near pipes and cables that have nothing to do with the leak.
Tarmac, block paving, concrete and gravel
Whatever covers the drive, the survey is done from above it. Water squeezing out of a pressurised pipe makes a hiss that travels up through the ground, and a ground microphone finds where that hiss is loudest. Plastic pipe muffles the sound, so on plastic, or on a leak too faint to hear, we switch to tracer gas, a hydrogen and nitrogen mix. It slips out through the same hole as the water, and a detector above finds where it comes up.
The surface does matter once it is time to open up. Some finishes can be lifted and relaid with barely a trace, while others will always show where the hole was. Knowing which kind you have means the finished drive is no surprise, and you can decide early who will make good the surface:
Block paving: the blocks over the leak lift out and can go back
Tarmac: cut out in a neat square and patched, and the patch usually shows
Plain concrete: cut, broken out and recast
Gravel: raked aside, then raked back once the pipe is mended
Imprinted concrete or resin: hard to match, so expect a visible repair
Marking one spot
Nothing is marked on the strength of one test. On a buried supply pipe, that usually means listening finds the loudest point and tracer gas then confirms it. The spot goes on the drive, with a photograph, only after two methods have agreed, so whoever opens up knows where the first cut belongs.
A mark made from the surface shows the best place to start digging, but it is not proof. It rests on readings from equipment above ground, and a leak is only proven once the damaged pipe is in plain view. For no find, no fee on home water leaks, detection counts as successful once the leak is narrowed to one room, or to an area of drive about 5 m by 5 m.
No find, no fee on home water leaks covers one leak on a water main up to 30 m or the hot and cold supply pipes, at least half a litre a minute, where we also carry out the access and repair. It does not cover central heating, shared mains, businesses or leaks that come and go. A supply pipe longer than 30 m, or one whose route nobody knows, is outside it too. Full conditions are on our terms page.
Opening up and putting the surface back
Most of the time we can mend the pipe as well. That repair gets its own quote, separate from the detection price, and a figure given beforehand only holds if we fix the pipe there and then, on the day we find the leak. Our repairs carry a 3 month guarantee from the day of the work. It covers the length of new pipe and the joints we add, while the old supply either side of the repair sits outside it.
A worn old pipe can start leaking at another weak spot once one section has been tested or mended, and any work there is quoted separately. Our terms also say that digging down to a pipe can disturb nearby pipes, fixtures and finishes, such as the drive itself. Unless our negligence caused the damage, putting them right is charged separately. Ask about the surface when the repair is quoted, and plan where the car goes while the hole is open.
Who pays for a water leak under the driveway
In most cases your water company is responsible for its main in the road and for the short connecting pipe between that main and your boundary or meter. The rest, up to and into the house, usually belongs to the property, so a leak under your own drive is normally yours to fix. Where one pipe serves several homes, such as a row of bungalows down one long drive, those owners usually share it. Your water company can tell you how this applies to your address.
Ring your insurer before you book anything. Ask if trace and access cover is part of your policy, and if the insurer has to agree to the work before it is booked. Once the visit is fully paid, you receive our written report, giving the location, methods, readings and photographs. The insurer, not us, decides what it pays. Some water companies reduce the bill for water lost through a leak on the customer's pipe once it has been fixed, so ask yours what proof it wants.