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Leak allowance

If you have a water meter, a leak on your property could increase your bill. If you fix it within four weeks of being made aware of it, we may cover the cost of the lost water. 

Once your leak is fixed, and you’ve filled in the leak fixed form, you’ll need to complete the leak allowance form. We’ll review this and, if it’s approved, we’ll credit your account with any charges added to your bill because of your leak. 

We can only issue a leak allowance if: 

  • The leak is repaired within four weeks of us first notifying you or when the leak was identified 
  • We can confirm the leak’s been fixed with a plumber’s details and invoice, or a Thames Water job number if we did the repair
  • The leak wasn’t fixed under Section 75 of the Water Industry Act
  • The leak allowance is claimed within three months of the repair date – even if you haven’t received a water bill yet 

Please see our leakage code of practice for full details. 

Completing the form

Make sure you complete all parts of the form, including the meter readings. Tell us as much as you can about your leak – it helps us work out any allowance accurately and quickly. 

For help finding or reading your meter, view our step-by-step guide to water meters

After you’ve completed your leak allowance form, we'll compare readings from before, during and/or after your water leak. We'll then decide if you qualify for the leak allowance.  

Your payment method and billing date will continue as normal while we look at your application. 

Download leak allowance form

You can email your completed form to or post it to Thames Water, PO Box 286, Swindon SN38 2RA.

Tenants in rented properties

If you don’t own the property, please contact your landlord immediately. You also need to check your tenancy agreement to see who’s responsible for any repairs.  

Once your leak has been repaired, you can apply for a leak allowance to cover the cost of any water lost as a result of the leak.  

How we work out your leak allowance 

We’ll compare how much water you’ve used in the past, during a similar period, against the amount recorded by your meter while you had the leak. We’ll calculate the difference in cost and add this amount to your account. We will also send you an adjusted bill that reflects your leak allowance reduction. 

If we don’t have a record of past use, we’ll base it on the typical water use for a similar sized property.