Water pollution

Mains water

United Utilities provide water to households and businesses in the North West. They also take away and treat the North West's waste water.

Private water supplies

Private drinking water supplies are water supplies which are not provided by United Utilities, but are the responsibility of their owners and users. All private water supplies can pose a potential threat to health unless they are properly protected and treated.

How we monitor private water supplies

We carry out risk assessments, sampling visits, investigations and analyse samples. 

A risk assessment is a check on the condition of the supply. It involves looking at the source of the supply, the surrounding area and anticipating what might lead to contamination. It will also involve looking at storage tanks pipework and treatment systems. The risk assessment identifies any actual and potential hazards that may affect the health of those drinking the water, so that improvements can be made to ensure the quality of the water supply and safeguard the health of those using it.

How often we monitor private water supplies

  • Commercial and larger domestic supplies (all supplies of any size that are supplied as part of a commercial or public activity and large domestic private supplies serving 50 or more people a day) - a full risk assessment to be completed every five years and sampled at least twice a year.
  • Small supplies (two or more dwellings but less than 50 people using supply) - a risk assessment must be completed once every five years and monitored at least once a year.
  • Small single supplies (water is supplied to a single dwelling for domestic purposes only) - these supplies will not automatically be included in the sampling regime. Sampling and risk assessment will only be undertaken if requested to do so by owner or occupier. If you want your supply assessing the charges listed below apply and in the event of failure we have a duty to ensure the supply is made satisfactory.
  • Private distribution systems (water supplied by United Utilities which is further distributed by third party pipes, for example, caravan and camp sites) - a risk assessment must be carried out and a sampling programme devised based on the results.

How we charge for monitoring private water supplies

We charge for monitoring services. We also pass on the cost of the laboratory analysis, at cost, to the supply owner, up to a maximum of £500. If the analysis costs more than £500, we will cover the difference.