Each year over 36,000 individual tests are carried out on over 3,600 samples that we take to make sure your drinking water is clean and drinkable at all times. As best practice, we follow quality standards or 'Prescribed Concentrations or Values' (PCVs) from both European Directives and UK regulations. We also follow the World Health Organisation's Guidelines for Drinking-water Quality.

To be sure that we're measuring up to these PCVs, we monitor the quality of water at every stage, including:

  • at our raw water reservoirs
  • as it leaves our water treatment works
  • at our treated water service reservoirs
  • following a shutdown or burst main repair
  • before new mains are connected
  • at our customers taps

We have two water supply zones; Sulby and Douglas, each with its own water treatment works. These water supply zones are split into a further three water quality zones where we check the quality of drinking water as it reaches our customers.

There is no cause for concern if our sampler comes to your house for a water sample - our database selects random addresses within each water quality zone. With your permission they will take a sample of water; usually from your kitchen tap, which is taken to the Government Lab for analysis.

Before taking any samples, we need to make sure there are no bacteria in the tap which could affect the result. To do this, we squirt a diluted bleach solution into the spout of the tap. We then run the tap again before taking samples. We make sure the water is run thoroughly afterwards to get rid of any remaining bleach solution.

Occasionally, the results from samples need further investigation, in which case we'll be in touch. Normally there is nothing to worry about and you can carry on using your tap as you usually would.

The majority of our samples are tested at the Government Lab and a few are sent to our off Island contract laboratory. All test results are recorded and monitored. On rare occasions where parameters fail we will investigate.

Our test results are published in our annual Drinking Water Quality Report.

Water quality information for your area can be supplied on request. If you would like this information please contact us.

If you're concerned about your drinking water, please contact us so we can investigate the problem. If appropriate, we'll take samples for analysis and let you know the results.