An investigation by the Guardian suggests EU countries will share laboratory capacity but UK rules mean products cannot be tested abroad.

It claims that the safety of tap water in the UK could be at risk because water companies are unable to use products to clean it, industry insiders have said, as all the laboratories that test and certify the chemicals have shut down.

People in the industry have called it a “Brexit problem” because EU countries will share laboratory capacity from 2026, meaning that if the UK was still in the EU, water companies would be able to use products that passed tests on the continent.

But UK rules mean products cannot be tested abroad; they have to be tested in the country in a certified lab, of which there are now none.

Photo credit: Skitterphoto

If companies are unable to keep contaminants out of the water supply, it can cause a danger to health. This year, thousands of people in Devon became unwell after the cryptosporidium parasite was detected in the supply. Schools and businesses had to temporarily close and it negatively affected the local economy. Some households had to boil their tap water for a month to remove the contaminant.

Under the rules of water regulators across the UK, including the Drinking Water Inspectorate (DWI), every item or chemical that comes into contact with drinking water has to be tested in stringent conditions, under an EU-derived law known as regulation 31. This ensures these products are safe to use, do not leach dangerous chemicals into the drinking water supply and do not encourage the growth of dangerous microbes.