The Clean Water Bill will reshape how water is regulated in England and Wales. Yet nearly half of last year’s drinking-water compliance failures in England arose on the customer’s side of the boundary. Samantha Duffy of NSF explains why the fittings inside homes and buildings need a clear place in the new regime.
By Samantha Duffy, Senior Manager of Global Water Programs, EU and UK Schemes, NSF
Most of the debate about water reform has centred on bills, investment and environmental performance. Far less attention has been paid to the final stretch of the system, the pipes, taps and fittings on the customer’s side of the boundary. This is where a substantial share of drinking-water quality problems now begins.
The Clean Water Bill, announced in the King’s Speech in May 2026, is set to bring the functions of Ofwat, the Drinking Water Inspectorate (DWI) and the water functions of the Environment Agency and Natural England into a single regulator. As the detail is developed, the last metre deserves a place in the design.
What the inspectorate found
The DWI’s report for 2025 confirms that public water supplies in England remain of very high quality, with 99.97% of more than 3.5 million tests meeting the required standards. The failures that did occur, however, were concentrated in one place. Of 982 compliance failures, 447 related to consumers’ own distribution systems. Of the 586 water-quality events notified to the inspectorate, 217 or 37% occurred on consumer premises. The picture in Wales is similar, with 32 of 91 failures and 25 of 65 events attributed to consumers’ systems.
These are not only legacy problems. Most of the 72 nickel failures recorded in England occurred in consumer systems and were commonly linked to new taps or fittings, and nickel accounted for 18% of all chemical failures. Lead failures are still driven mainly by lead pipes and internal plumbing in older properties, but they have also started to be reported in new buildings. Some of the risk is being installed today.
A framework that relies on the end of the chain
The Water Supply (Water Fittings) Regulations 1999 require every water fitting connected to the public supply in England and Wales to be of an appropriate quality and standard, and suitable for the circumstances in which it is used. Scotland and Northern Ireland have equivalent requirements. Water companies enforce the regulations, and failure to comply is a criminal offence.
Legal responsibility rests with those who install and own the fittings. There is no current requirement for a product to be shown to comply before it is sold: manufacturers can legally produce fittings that do not meet the regulations, and merchants can legally sell them. NSF has described this as a compliance paradox. The organisations with the greatest technical knowledge of a product carry the least legal obligation for its compliance, while those least equipped to judge it carry the most.
Regulation 4 sets out how a fitting may demonstrate the required quality and standard. Water Regs UK’s non-statutory guidance identifies three common forms of evidence that water undertakers may consider: appropriate marking under the Construction Products Regulations, product certification by a body accredited to ISO/IEC 17065, and reports from a laboratory accredited to ISO/IEC 17025 for the relevant tests. The water undertaker ultimately determines whether the evidence is sufficient. The difficulty lies not in the absence of recognised evidence, but in ensuring that it exists before a product reaches an installer.
What the public believes
A system that depends on installers and property owners also depends on their understanding of it. Research commissioned by NSF suggests that understanding is limited. In 2025, NSF (via Opinium) surveyed 2,000 UK adults, weighted to be nationally representative. More than half (52%) had never heard of the Water Fittings Regulations, and 30% believed that every water fitting sold in UK shops is automatically compliant. Misconceptions about the rules were common: 19% believed they apply only to new homes, 17% that compliance is voluntary for homeowners, and 14% that a non-compliant fitting is permitted if the local council is told first.
Among homeowners, 80% had never checked whether their fittings comply, and 59% had no plans to do so. More than half (52%) considered it unlikely that a non-compliant fitting would ever be discovered in their property.
A regime that relies on informed installers and property owners cannot work as intended when more than half of the public has never heard of it.
Three questions for the new regulator
Regulatory reform offers an opportunity to strengthen this part of the system. Three questions are worth answering before the detail is settled.
The first is ownership. Responsibility for the last metre is currently spread between water companies which enforce the fittings regulations; the drinking-water regulator, which oversees quality at the tap; and the people who install and own the fitting. A single regulator could provide a clearer line of sight across all three.
The second is measurement. The DWI already reports how many failures and events arise in consumers’ systems. Publishing what fittings inspections find, and what action follows, would show where the risk lies and whether enforcement is reducing it. In one case in its latest report, the inspectorate recommended water fittings inspections beyond the properties immediately affected. Problems in the last metre rarely stay in a single home.
The third is where responsibility starts. Independent certification by bodies accredited to ISO/IEC 17065, supported by accredited testing, already allows manufacturers to demonstrate compliance before a product is sold. Encouraging the supply chain to make independent certification the norm would mean the evidence exists before a product reaches an installer, rather than being sought afterwards.
Reaching the tap
Public confidence in drinking water is formed at the tap, not at the treatment works. The DWI’s figures show that the quality of what reaches the tap now depends heavily on decisions made after the water leaves the network: which products are bought, who installs them, and what evidence supports them. If almost half of compliance failures arise within customers’ own systems, regulatory reform that stops at the boundary will address only part of the risk. The question for the new regulator is no longer whether the last metre matters, but who will be responsible for it.
About the author
Samantha Duffy is Senior Manager of Global Water Programs, EU and UK Schemes, at NSF, a global organisation dedicated to protecting and advancing public health. Through science-driven standards, testing, certification, research and advisory services, NSF helps improve the safety, quality and trustworthiness of food, water and wellness products and systems worldwide. NSF certifies water fittings to Regulation 4 through NSF REG4, and its Oakdale laboratory is designated by the DWI for Regulation 31 testing.
