High water bill but no sign of a leak?

Why a water bill suddenly goes up

Before assuming there's a leak, it's worth ruling out the everyday causes. A higher bill can come from:

• An estimated reading that was too low for a while, followed by a catch-up bill once a real reading is taken.
• A faulty or misread meter, which can record water you haven't used.
• A change in how much water you use, such as new people in the house, guests, a new dishwasher or garden watering in summer.
• A hidden leak, which can be a running toilet, a leaking pipe under a floor, or a damaged supply pipe underground.

The simple meter test you can do yourself

If you have a water meter, this test shows whether water is moving through your pipes when nobody is using any. It takes about an hour.

• Turn off every tap, appliance and anything else that uses water. Make sure no one flushes a toilet or runs the heating top-up.
• Find your water meter. It's usually near the front boundary of the property, under the kitchen sink, or in a pavement box. Lift the cover carefully.
• Write down the reading, including the small dial or the digits after the decimal point.
• Leave everything off for an hour, then read the meter again.
• If the numbers have moved while nothing was on, water is going somewhere. A moving meter or a spinning small dial points to a leak.

Common hidden causes

• A running toilet. A worn flush valve can let water trickle into the pan all day and night. It's one of the most common causes of a high bill, and easy to miss.
• A leaking underground supply pipe between the meter and your house. You won't see it, and it can lose a lot of water before any damp shows.
• A slow leak under a floor or behind a wall, especially in kitchens and bathrooms.
• An outside tap, garden pipe or irrigation system left dripping or damaged.
• A heating system that keeps topping itself up, if your boiler is connected to a filling loop that's been left open.

What to do next

Some water companies offer a one-off allowance or adjustment for leaks on the supply pipe once it's been repaired. Ask yours before you pay the bill, and keep any report we provide as evidence.

• Do the meter test above so you know whether water is really moving.
• If the meter is moving with everything off, call us. We'll pinpoint where the water is escaping.
• If the meter is not moving and your usage looks normal, contact your water company and ask them to check the meter and the readings behind the bill.
• If you're not sure, or you don't have a meter, get in touch and we'll tell you honestly whether a visit is worthwhile.

How do I know if I have a leak or a faulty water meter?

Run the meter test above. If the meter moves while everything is off, water is escaping, so it's a leak. If it stays still, the leak is unlikely and the meter or the bill itself may be at fault. Your water company can check the meter.

Can you find a leak on the pipe outside my house?

Yes. We investigate underground supply pipes as well as leaks inside the property. We use methods such as tracer gas and pressure testing to pinpoint the exact spot, so only the right area needs to be dug up.

Will my water company refund me for a leak?

Some do, usually for leaks on the supply pipe once they've been repaired. Policies vary, so check with your water company. A clear report of what was found and when it was fixed can help.