UK updates Regulation 31 product approval tracking

By Rebecca Stone

A searchable UK list of drinking-water product approvals went live in August 2025, with updates on new applications and regulatory changes posted twice daily.

The service centralizes information about chemicals and construction products used in public water supply. It gives industry stakeholders a current view of which substances and products regulators have approved for that use.

The DWI's summary says Regulation 31 “prohibits water companies from applying, or introducing into water, any substance or product that may impact drinking water quality.”

That duty covers every chemical and construction product used by water undertakers. Contact can change taste or odour, while leaching can release harmful substances. Regulation 31 therefore permits approvals only where use will not prejudice drinking water quality and, ultimately, public health.

The rule governs both use and approval. A chemical or construction product must clear the approval route before a water company can apply it or introduce it into water. For undertakers, that check spans every stage from abstraction to delivery at a consumer's building.

Ben Thorpe, Regulation 31 inspector at the Drinking Water Inspectorate, explained the regulation and recent improvements to the approval process. His account covers how industry tracks submissions and understands compliance, as well as the legal duty behind each decision.

The wider framework comes with a cited performance marker. The 2024 Environmental Performance Index ranked the United Kingdom joint first, at ≤1% percentile, according to Block et al.'s report for the Yale Center for Environmental Law and Policy. The result sits within a source-to-tap framework designed to protect public water quality.

Who approves products in the United Kingdom?

Approval responsibility differs by jurisdiction. The DWI operates the approval process across the United Kingdom, but each relevant regulator issues its own approval letter:

• England and Wales: Drinking Water Inspectorate.
• Scotland: Drinking Water Quality Regulator.
• Northern Ireland: Drinking Water Inspectorate Northern Ireland.

Those letters remain separate even though the public register brings the decisions into one searchable place. Users can trace a product by name, type or approval holder without treating one jurisdiction's authorization as another's.

Regulation 31 requires publication at least once a year of every substance and product approved or refused and every approval revoked or modified. The August 2025 upgrade makes that required information live and searchable.

The service posts updates twice daily on newly received applications for assessment and on changes to approvals, refusals, revocations and expired products. DWI launched the changes to improve transparency and usability for the industry.

In DWI's account, the improvements should make ongoing monitoring “clearer and more efficient for all users.” The practical difference is comparable to consulting a live compliance ledger rather than an annual archive.

How does the application portal work?

The separate Regulation 31 application portal has also been upgraded and remains under development. Anyone can submit an application for a product or substance intended for public drinking-water supply through that portal.

For applicants, the central workspace supports three functions:

• Track the status of an application.
• Monitor supplier engagement with the application.
• Upload supporting documentation in one location.

DWI says these functions streamline the approval process and give applicants clearer visibility throughout an application's lifecycle. The continued development of the portal and associated guidance carries no stated completion date, so no separate project deadline yet governs that work.

The inspectorate also provides detailed guidance on changes to approved products, requirements for products with a small surface area in contact with drinking water, and other common regulatory queries. The material sits alongside the searchable list at DWI's Regulation 31 page: Drinking Water Inspectorate Regulation 31 information.

The next formal checkpoint is the next annual publication of approvals, refusals, modifications and revocations. Until the relevant national regulator issues its approval letter, a product or substance has not completed the Regulation 31 approval route required for use in public drinking water.