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Regulations and standards

We are committed to providing reliable and high quality water supplies which fully meet all European and UK standards.

This is a vital contribution to protecting the health and well–being of the water communities we serve. To make sure that our customers have total confidence in the water we supply, we’re dedicated to open publication of our quality performance.

What is the law?

The European Union have recently issued revised quality standards relating to drinking water. These and some stricter national standards have been adopted and written into national law in The Water Supply (Water Quality) Regulations 2000 (Amendment) Regulations 2007.

Who ensures the standards are met?

The primary responsibility for enforcing the standards and regulations lies with the Drinking Water Inspectorate (DWI). They independently assess the performance of every water company and report annually. Local authorities also have some responsibility for checking drinking water quality through their Environmental Health teams.

What do the standards cover?

They cover chemicals, micro-organisms and aesthetic qualities such as colour, clarity and taste. The Water Supply (Water Quality) (England) Regulations 2000 have a fundamental difference from the previous Regulations. They make a distinction between those parameters which are considered to be important to health (mandatory) and others which largely affect the appearance and taste/smell of water (indicator).

The Regulations also specify the frequency of monitoring for the different parameters such as microbiological and those chemical parameters that may be affected by treatment processes.

How are the target levels set?

The standards, which are called ‘Prescribed Concentrations or Values’ (PCVs) are set in a variety of ways. Most define maximum and a few minimum levels, while some state the percentage of samples which must meet the required standard.

What units of measurement are used?

Many of the measurements are very near the limits of detection, even with the most sophisticated instruments. For example, the individual pesticides standards (one part in ten billion or 0.1 nanogramme per litre) is extraordinarily difficult to achieve and demonstrates the inherent water quality ensured in the UK.

What happens if a standard is not met?

Any exceedance of a standard is always immediately investigated and remedial action taken. In the vast majority of cases such exceedances are minor and temporary in nature. However, all must be reported to the DWI, who can further investigate if they choose.

In the rare circumstances that an exceedance of a standard cannot be rectified promptly, then the Drinking Water Inspectorate can require us to take further action. Provided there is no risk to health, these actions are written into a legally binding commitment to implement programmes stating how and when we intend to achieve compliance.