High water bill? How to check for a leak
If your bill has jumped and your habits have not changed, water is probably escaping somewhere between the street and your taps.
Turn off every tap and water-using appliance, note the meter reading, wait 30 minutes without using any water, then read it again. If the number has moved, you very probably have a leak. If your meter sits at the boundary, a common hidden culprit is the underground supply pipe between the boundary and the house, which Ofwat says is usually the homeowner's to maintain and repair.
The 30-minute meter test
- Find your water meter. It is usually in a small chamber under a cover near the boundary, or inside where the supply enters the house.
- Make sure nothing is using water: taps, toilets, washing machine, dishwasher, outside taps, water softener, and any tanks that might be filling.
- Write down the full reading, or take a photo of it.
- Wait at least 30 minutes without using any water. Longer is better, and overnight is best.
- Read the meter again. If the number has moved, you very probably have a leak. Then close your inside stopcock and repeat the test. If the meter still moves, the leak is probably on the supply pipe outside. If it stops, the leak is inside the house.
Many meters have a small dial or spinning indicator that moves with even a slow flow. If it is turning with everything off, that is enough to know.
Which pipe is yours?
In England and Wales, the water company generally looks after the pipe up to your property boundary. The stretch from the boundary to the house, the supply pipe, is usually the homeowner's responsibility, along with all the plumbing inside. Water that passes through your meter is charged to you, and arranging the repair is normally your job. Some water companies offer help, such as free leak location or a contribution to the repair, so ask yours first. If your meter is inside the house, a leak on the pipe before it will not show on your bill, but it is still yours to repair.
In Scotland the supply pipe inside your boundary is also the owner's responsibility, but most homes pay for water through council tax, so a leak will not show up on a bill at all. Watch for the other signs instead.
Water companies can offer a one-off allowance on the bill once a supply-pipe leak is repaired, but the rules vary by company. Ask yours before you pay the bill in full.
How much a slow leak costs
A leak you cannot see can still move a lot of water. A small, steady leak of 1 litre a minute adds up to over 500,000 litres in a year.
Finding an underground leak
Digging a trench along the whole supply pipe to find a leak is slow, messy and expensive, especially under a driveway. ADI's engineers use acoustic listening, leak correlation and tracer gas to pinpoint the spot from the surface, so the repair usually means one small excavation instead of a trench.
ADI's No Find No Fee terms apply to single plumbing leaks at an individual property losing at least 0.5 litres a minute, with water mains covered up to 30 metres. Central heating, structural and pool leaks are excluded. Ask on the phone if you are unsure whether your job qualifies.
Common questions
Does home insurance cover a leaking supply pipe?
Trace and access cover, where you have it, can pay to find the leak and dig down to it, though many policies only pay if the leak has caused damage they cover. It does not normally pay to repair the pipe itself. Some buildings policies cover accidental damage to underground pipes you are responsible for, and some pay for lost metered water up to a small limit. Otherwise the lost water is dealt with through your water company's leakage allowance. Check your policy wording.
What if I do not have a water meter?
Without a meter the bill will not show a leak, so look for the other signs: low pressure, a wet patch outside in dry weather, or the sound of running water with everything off.
More leak guides
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Signs of a hidden leak
Damp patches, a meter that never stops, a boiler that keeps losing pressure, and the other clues that water is escaping somewhere you cannot see.
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What to do when you find a leak
The first hour: stopping the water, keeping safe, the photos your insurer will want, and who to ring in which order.
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Water coming through the ceiling
Where the water is most likely coming from, when a stained ceiling becomes dangerous, and what insurance tends to cover.
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Boiler losing pressure
If you are topping the boiler up every few days, the water is going somewhere. How to tell a boiler fault from a hidden heating leak.