Why is my bill higher than expected? | Dwr Cymru Welsh Water
Dwr Cymru Welsh Water

Thursday, 20th February – 10:00

We continue to deal with the impact of severe weather and flooding over the last few days, particularly in the Monmouth area.

We have accessed our water treatment works at Mayhill and assessing the damage so that we can get works back up and running. This will take some time to do, given the impact of the flooding and the work needed to bring the operation back into normal service.

In the meantime, we are continuing our extensive tanker operation throughout the town to maintain supplies to customers. This has involved a fleet of more than 40 tankers, which have been pumping water into the system and supplies have been kept going for the vast majority of our customers. We are making every effort to maintain this in the coming hours and days, while we get the works up and running.

Some customers in Monmouth have been asking our colleagues in the area if they need to boil their tap water: our answer is no. We’re providing bottled water as a precaution in case supply is interrupted and for a small number of customers without water.

We have also set up three bottled water stations for those who have seen their supply interrupted. These will be open from 8am til 8pm and can be found at:
• Monmouthshire Comprehensive School – Dixon Road – NP25 3YT
• Redbrook Road (opposite Lidl’s car park entrance) - NP25 3LY
• Trellech Primary School - NP25 4AX

We ask those who still have water not to visit these sites, as we need to prioritise customers with an intermittent supplies.

We have delivered bottled water to all properties as a precautionary measure and will also continue to deliver bottled water proactively to our vulnerable customers on the Priority Services Register, such as the elderly, disabled, or those with young children.

We want to thank our customers for bearing with us while we carry out this work to keep things going.

We will post regular updates here and social media.

My Account Water Meter Why is my measured bill higher than expected?

Why is my water bill higher than expected?

If you've received a measured water bill which is higher than you expected, our below list may help you work out why.

There are a number of reasons why your bill may appear high:


  • Your previous bill was based on an estimated reading which was too low. Therefore, your latest bill will include any charges not billed on your previous bill.

Here is an example:

Average usage per bill - 45 cubic metres (m3) or 90m3 for two bills.

Bill Your billed usage  
Previous bill 35m3 (estimated)  
Latest bill 55m3 (actual)  
Total 90m3  


  • Your latest bill was for a longer period than your previous bill. The longer the bill period, the more water you will use.

Here is an example:

Bill Your billed usage  
Previous bill 26m3 in 150 days  
Latest bill 33m3 in 193 days  


  • If the number of people living at the property has increased between your bills.

Here are some examples:

  • You had a baby.
  • You had visitors to stay.
  • A friend or relative has moved into the property with you.

Other reasons why your bill is higher than you expected...

  • A dripping tap which can waste at least 18 litres a day. This would cost about £20 a year!
  • Renovation or decorating work which means you have used more water than usual.
  • Using a garden sprinkler or hose more often due to dry weather. A garden sprinkler can use up to 1000 litres an hour which is the same usage as a family of four in 48 hours.
  • A leak on an appliance e.g. a washing machine or boiler.
  • A leak on any pipework which is your responsibility.

How can you check for a leak?

If you're worried you may have a leak, you can carry out a couple of easy tests. Follow the below instructions:

Overnight Test 1:

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

What did you find?

  • Overnight Test 1 - If your reading changed, there could be a leak. Please call us on 0800 052 0140. We will arrange for an inspector to visit. If your reading didn't change, please carry out overnight test 2 below.

Overnight Test 2:

  • Leave the internal stop tap on.
  • 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.

What did you find?

  • Overnight Test 2 - 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 overnight tests, there is no leak on your water supply or inside your property.

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