Testing water quality

We make sure your drinking water is clean and drinkable at all times. There are certain legally enforceable quality standards from both European Directives and UK legislation that we are measured against. These are known as ‘Prescribed Concentrations or Values’ (PCVs for short).

In order to be sure that we’re measuring up to these PCVs, we monitor the quality of water as it leaves our water treatment works and service reservoirs. Throughout the North West region, these treatment works and service reservoirs look after some 261 individual areas that we’ve designated as water supply zones. The water supplied to each zone is usually from one particular water treatment works or service reservoir.

We also measure the quality of drinking water as it reaches our customers, and we do this by taking water samples from addresses selected at random within each particular water supply zone. The samples are tested at our laboratories and the results compared with the required legal quality standards. All the test results are recorded on the Drinking Water Register.

Click here for more information on water quality. We also have a helpful guide which provides advice on keeping your tap water in tip-top condition.

Lead sampling

There are many factors that can have a considerable influence on lead concentrations e.g. there can be a 40% variation depending on the temperature of the water alone. As a result of this, the meaning of an individual measurement is very limited and isn't likely to reflect your overall risk to exposure of lead in drinking water. Every year we do encounter a few samples that contain lead concentrations greater than the 10 µg/l standard, and when we do it is highly probable that there is a lead pipe present, but the only way to be sure is to determine whether or not you have lead pipes. The key point is that lead at any concentration poses a risk and exposure should be kept to a minimum.

Find out more about lead pipes

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