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Water Quality

Water quality information and guidance for mains and private water supplies, swimming pools, bathing waters and Cardiff Bay


Private Water Supply

A private water supply is a supply of water other than that provided by a water company.  The majority of private water supplies are on boreholes that are generally ground water fed, but influenced by surface water and can be weather dependent.

Under the Private Water Supply (Wales) Regulations 2010, we have a duty to undertake routine inspections, risk assessments and water monitoring of private water supplies to make sure the water is safe for drinking, cooking and washing.

If you are a large or small supply, we will be carrying out a risk assessment and water monitoring.  Risk assessments enable us to identify any potential impacts on the supply and how they can be addressed. A water test informs us about the quality of your water at that point in time.

We will also inspect any piping, tanks and treatment systems and collect water samples for laboratory analysis to establish that the water is safe for drinking.

If your house is the only property connected to the private supply, then we will only carry out an inspection at your request.

You can contact us if:

  • You would like to have an assessment of your water supply or have your water tested.
  • You have any queries or concerns about your supply.

Mains Water Supply

The majority of domestic properties are supplied with drinking water direct from a mains pipe which is supplied by Welsh Water.

It is Welsh Water’s responsibility to ensure that the water supplied is fit for human consumption and meets current standards. 

Mains water suppliers in England and Wales are regulated by The Drinking Water Inspectorate. 

They ensure that water companies supply safe drinking water that is acceptable to consumers and meets the standards set down in law. 

The legal standards for drinking water are set out in The Water Supply (Water Quality) Regulations 2000.

Filling glass with water

Report a Problem

Should you experience a problem with your mains water supply please contact Welsh Water:

0800 052 0130

Report Online



Swimming Pools

Where necessary routine samples are taken from public swimming and spa pools throughout the year to check that water quality is satisfactory.


Cardiff Bay Water Quality

All water quality data collected is presented and interpreted in a quarterly report. These reports are available for inspection at the Harbour Authority's office.

Further information can be found on the Harbour Authority website.


Bathing Water

Every summer between May and September Natural Resources Wales monitor the quality of bathing waters within the Vale of Glamorgan and Bridgend.

The following beaches are sampled: Newton Beach, Sandy Bay, Trecco Bay, Rest Bay, Jacksons Bay, Whitmore Bay, Cold Knap and Southerndown.

Further information and recent results can be obtained from Natural Resources Wales.