Testing if you have a water leak at home


We want to do everything we can to encourage our customers to detect and repair leaks as quickly as possible. This helps us to reduce leakage and for you to potentially save large amounts of money.

Leak Test 1 - supply leak

  • Turn off your internal stop tap and take a meter reading.
  • Leave the stop tap turned off overnight.
  • Take a second meter reading the following morning and turn your internal stop tap back on.

If your reading changed, there could be a leak. Please call us on 0800 052 0140 and we will arrange for an inspector to visit. If your reading didn't change, please carry out overnight test 2 below.

Leak Test 2 - internal leak

  • Leave the internal stop tap on and take a meter reading when you go to bed.
  • Don't use any water after you have taken your reading.
  • Take a second meter reading the following morning.

If your reading changed when no water was used, this would indicate a leak inside your property. Please contact a plumber to find and fix the leak at your cost. Or if you rent the property, you may wish to contact your landlord.

If your reading didn't change on either of the tests, there is no leak on your water supply or inside your property.

If you do not have a meter

  • Listen out for a hissing noise or knocking in the pipework
  • Turn off the water supply at the internal stop tap
  • Check that no water comes out of the kitchen cold water tap when the internal stop tap is turned off

If water still runs, the internal stop tap could be faulty and you will need to call a plumber)

What else can I do?

If you're still worried about the amount of water you use, more information can be found in our 'Where does my water go?' leaflet.

Meter logger

If you remain concerned following the above tests, you may wish to consider a temporary meter logger. This is a device which can be fitted on the water meter for 14 days (available for meters up to 25mm) to record how much water you use in more detail. A comprehensive report will be provided to help you understand how, and when, the water is being used.

The meter logger will cost you £70 (inclusive of VAT) and we will refund the fee if the leakage is on Welsh Water's pipes with 25 working days.

You can apply for a meter logger by completing our paper meter logger application form.