For a home in Cardiff, Dŵr Cymru Welsh Water is the main regional benchmark. Its forecast 2026/27 household average is £683 a year.
Dŵr Cymru Welsh Water serves most homes in Cardiff. Water-company boundaries can cross postcode areas and clean water may come from a different company than wastewater.
Monthly and weekly equivalent
The annual company average works out to £56.92 a month or £13.13 a week. Your payment plan may collect over ten rather than twelve months, so instalments can differ.
How Cardiff compares with the national benchmark
The £683 regional company average is £44 above the £639 England and Wales combined average for 2026/27. This compares company-wide averages; it does not measure bills specifically within Cardiff or predict the charge for an individual address.
Household-size examples
These planning estimates adjust the Dŵr Cymru Welsh Water company benchmark for typical occupancy. They are not tariff quotes.
| Household | Annual estimate | Monthly |
|---|---|---|
| 1 person | £428 | £35.67 |
| 2 people | £616 | £51.33 |
| 4 people | £926 | £77.17 |
Coverage around Cardiff
Dŵr Cymru Welsh Water is associated with postcode areas including CF, CH, LD, LL, NP, SA, SY. This is only a regional guide: postcode areas can contain more than one appointed company, and wastewater may be billed separately.
What changes a Cardiff bill?
- A metered home pays for measured use plus fixed charges.
- An unmetered home normally pays according to historic rateable value.
- Occupancy and habits strongly affect metered consumption.
- Support tariffs and WaterSure can reduce eligible bills.
Calculate an estimate for your Cardiff home
The calculator below starts with Dŵr Cymru Welsh Water. Adjust the household size and usage level, and check the supplier against your bill. It models a regional combined bill, including where clean water is supplied separately; it does not calculate every local water-only tariff.
Check an unexpectedly high bill
If your bill is above this benchmark, compare the billing period and actual meter readings first. Our high water bill guide explains the checks to make. You can also compare metered and unmetered costs or read about help with paying your bill.