The safety of UK tap water could be at risk because water companies cannot use products to clean it, industry insiders said, as all laboratories that test and certify the chemicals are closed.
Industry insiders have dubbed it a “Brexit issue” as EU countries will share laboratory capacity from 2026, meaning if the UK was still in the EU, water companies could use products tested on the continent .
But UK rules mean products cannot be tested overseas; they must be tested in the country in a certified laboratory, which currently does not exist.
If companies are unable to keep contaminants out of the water supply, it can cause health hazards. this year, thousands of people in Devon fell ill after the cryptosporidium parasite was found in supplies. Schools and businesses had to close temporarily and this negatively affected the local economy. Some households had to boil their tap water for a month to remove the contaminant.
Under drinking water Inspectorate (DWI) regulations, any item or chemical that comes into contact with drinking water must be tested under strict conditions under an EU-derived law known as regulation 31. This ensures that these products are safe for use, do not leach dangerous chemicals into drinking water and do not promote the growth of dangerous microbes.
Labs must be Rule 31 certified, which means they perform all tests on chemicals, pipes, or other items to a specified standard. There used to be three such laboratories in the UK, but from 2021 there is none as they were all closed because they are expensive to operate.
This means that new products cannot be tested or used for water treatment and that products that must be retested every five years cannot be approved either. Whistleblowers at the water companies said this “restricts the availability of products in the market, which both threatens safety and reduces competition, which will raise prices and reduce the quality of service”. There are dozens of products waiting to be tested.
There are no plans for new labs. DWI could not give a date when a new lab might open or when the problem would be resolved. Water company insiders say the rule has indefinitely halted the use of any new products that remove contaminants from the water supply.
Those charged with cleaning the UK’s tap water at water companies said a lack of testing capacity had led to existing products leaking compliance and that they have since been withdrawn from the market. They said many of these products, which cannot now be actively used, prevent contamination from entering the water supply.
Trade group British Water told the industry: “The closure of laboratories offering this vital testing service has not only disrupted production lines, but has left suppliers struggling to meet the stringent demands of their customers.”
Cerys van de Vyver, the director of CV Water Consultancy, has worked in the water industry for decades, including at DWI.
“At the moment we have no testing facilities in the UK to meet the testing requirements of Regulation 31,” she said. “These are specific and highly focused laboratories. This creates some problems in adopting new innovative products because we don’t have an open laboratory at the moment.”
Van de Vyver said the situation in the EU is different: “In Europe, there is a planned harmonization of standards for EU members by December 2026. as part of the revised Drinking Water Directive. We look at what Europe is doing, obviously the events of the last few years mean we are in a different situation.
She added: “We are working safely at the moment but manufacturers are finding it frustrating because we can’t get products approved in the UK.”
“[The DWI] make sure all products in contact with drinking water are of the highest quality and we as a water industry have to abide by that and want to maintain the quality of our water.’
A DWI spokesman said: “While there are currently difficulties with laboratory capacity in the UK for Regulation 31 testing, this has no impact on consumers and no products will bypass the system. Rather, it is an operational difficulty within the water utility and supply chain system. Industry, regulators and government are working to increase capacity in the system.”
A spokesperson for Water UK said: “Regulation 31 is vital to ensure that the products we use to treat and transport our drinking water meet the highest standards. As a result of strict regulations, the UK has drinking water that is independently ranked as the best in the world. Water companies work with regulators and manufacturers to ensure the process works as efficiently as possible.
