Where you live
To find out about water quality in your area, including test results at customers’ taps, you can use our area of supply map or postcode search.
The files listed below give key information about water quality:
Taste and Odour
Why clean water is vital
A dependable source of safe drinking water is essential to life. Early methods of purifying drinking water without disinfection were only partially effective against the resilient microbes that can cause cholera, typhoid fever and dysentery.
When chlorination was used as part of properly designed water treatment systems in the early 1900s, these diseases were effectively eliminated. As a result, we have seen the UK annual death rate from waterborne diseases drop from 40 per 100,000 at the beginning of the 20th century to none. The standards of treatment and management mean that the water supply in the UK is among the safest in the world.
In order to provide you with safe, good quality drinking water we look after water quality from the source, through treatment and finally, at your tap.
Analysis and monitoring
Water quality is highly regulated. Our dedicated team carries out thousands of tests, taking samples 365 days a year from treatment works, reservoirs and customer taps to ensure that our water meets the required standards.
The result of any test is only as good as the sample taken, so a sample taken from a customer’s tap with defective plumbing, for example, could count as a ‘failure’ against the standards.
Sampling is almost a science in its own right, with over 30 types of sample containers and a wide range of techniques.
Microbiological testing provides an important measure of water quality and any non-compliance is taken seriously. We analyse water samples mainly for bacteria of the coliform group, which occur naturally in large numbers in soil and vegetation. These bacteria outlive many harmful bacteria and are therefore a sensitive indicator of water quality. If they are found in drinking water, it indicates that there is the potential for other harmful bacteria to be present.
However, as bacteria are so widespread, their presence may not always indicate a problem with the supply. If a sample does indicate the presence of coliforms, we immediately test more samples and investigate the circumstances.