(FAQ4) What products can be approved for use with drinking water?
Products that can be approved
Only products that are used by or will be used by drinking water suppliers in the United Kingdom – from the source, through treatment, to the point of supply to consumers’ premises – can be approved under the relevant regulations.
What types of products can be approved?
- Treatment chemicals: Flocculants and coagulants, disinfectants, not covered by BS EN (products for use in building water systems cannot be considered)
- Treatment process products: Adsorbents, ion exchange resins, membranes, on-site chlorine generators, filter media, vessels and containers, electrodialysis water treatment units, pressure vessels, products used for the physical treatment of water.
- Pipes and associated components including coatings: Polyethylene (PE) (including barrier and laminated), polyvinylchloride (PVC), acrylonitrile-butadiene-styrene copolymer (ABS), polyethylene terephthalate (PET), glass reinforced plastic (GRP), stainless steel, and lined metallic pipes.
- Site applied and in-situ coatings: coatings based on epoxy or polyurethane resins.
- Repair materials
- Water retaining structures
- Covers and linings
- Underdrains
- Products for emergency use with public water supplies
The current list of approved products can be found on our website.
Some products are covered under relevant European standards and cannot be considered for approval:
- Chemical products used for treatment of water, based solely upon a treatment chemical covered by a relevant BS EN standard
- Inorganic supporting and filtering materials used for treatment of water intended for human consumption, covered by relevant BS EN standards
Building water systems
Products used in customers’ premises, in public buildings are covered by different approval requirements and regulations The Water Supply (Water Fittings) Regulations 1999 (legislation.gov.uk), and cannot be approved under Regulation 31 of the Water Supply (Water Quality) Regulations.
For a comprehensive explanation, including the role of the approval bodies, see annex 1.
Swimming Pool water treatment
Many swimming pool treatment chemicals are covered by European Standards specifically developed for swimming pools. The Pool Water Treatment Advisory Group (PWTAG) can provide additional guidance regarding swimming pool water treatment – http://www.pwtag.org/. Details of these standards are available from British Standards Institution – http://www.bsigroup.com/.
GENERAL NOTE: the Drinking Water Inspectorate in unable to comment on:
- the suitability for use within building water systems or in the treatment of swimming pool waters, of any product approved under Regulation 31 of the Water Supply (Water quality) Regulations, including their fitness for purpose
- the use of any other treatment chemical, product/device or process within building water systems or in the treatment of swimming pool waters
All such enquiries should be made directly to:
- Water Regs UK Limited for building water systems
- PWTAG | The home of the Pool Water Treatment Advisory Group (PWTAG) for swimming pool waters
Annex 1 – What is the relationship between the approval schemes?
The Water Supply (Water Fittings) Scheme
This voluntary scheme is provided on behalf of the UK water industry to demonstrate compliance to the Water Supply (Water Fittings) Regulations.The scheme approves water fittings and materials, for use within consumers’ premises, to the requirements of the Water Supply (Water Fittings) Regulations 1999. For most non-metallic materials test methods and acceptance criteria for potential effects on water quality are specified in BS 6920[1]. These tests include odour and flavour, appearance, growth of aquatic microorganisms, leaching of metals, and cytotoxicity. The scheme normally only accepts test reports from laboratories that have been accredited (under EN ISO/IEC 17025) for BS 6920 testing by the United Kingdom Accreditation Service (UKAS).
Materials which meet the full test requirements of BS 6920:1 can be listed in the materials section of the Water Fittings and Materials Directory, published by the approving body. In many cases approval bodies will accept the use of listed materials in fittings without the need for any further testing, although mechanical testing of the fitting may be required.
Details of the approval bodies and the regulations can be found here – https://dwi.gov.uk/drinking-water-products/reg-31-approval/products-used-within-a-property-boundary/
[1] BS 6920 – Suitability of non-metallic products for use in contact with water intended for human consumption with regard to their effect on the quality of water
Regulation 31 Approval Scheme
The Drinking Water Inspectorate (DWI) operates the approval system for products used by UK water suppliers under the requirements of the relevant regulations on behalf of the national authorities. DWI can accept applications for approval of products used both before and at the treatment works and in water distribution systems up to the point of delivery to premises. The only products considered for approval under Regulation 31 are those sold to water undertakers in the United Kingdom for use with water intended for human consumption.
When considering non-metallic products for approval under the relevant regulations, however, the DWI does take into account the results of BS 6920 testing undertaken as part of the approval process for products. Where products have not been previously tested to BS 6920, normal requirements for approval will include satisfactory results in the BS 6920 tests – see Section 4.2 of our Advice Sheet 1 (https://dwi.gov.uk/drinking-water-products/advice-and-approval/Advicesheet1.pdf) for further details.
Products recommended for approval under Regulation 31 are listed in the “List of Approved Products for use in Public Water Supply in the United Kingdom” published on the DWI website – https://dwi.gov.uk/drinking-water-products/approved-products/index.htm.
DWI does not approve any product for use with drinking water – see https://dwi.gov.uk/drinking-water-products/faqs/FAQ2.pdf
The DWI only considers products (treatment chemicals and construction products) used in the PUBLIC WATER SUPPLY, i.e. between the point of source of water and the point of supply to consumers’ premises.
Table of Comparison
The following table summarises the differences between Water Supply (Water Fittings) approvals and those given under Regulation 31.
| Within buildings | In drinking water supply |
|---|---|
| Building water systems – consumer’s premises | From source to consumer’s premises (including treatment works) |
| Individual materials Final products, including pipes, fittings and assembled products etc | Treatment chemicals Final products, including treatment plant, pipes, fittings and assembled products |
| Legal basis – the Water Supply (Water Fittings) Regulations 1999 | Legal basis – the relevant regulations |
| Testing to Parts 1 to 3 of BS 6920 | Testing to Parts 1 and 2 of BS 6920, BS EN 12873 (relevant part), BS EN 15768 plus additional tests specified on a case-by-case basis |
| Direct effects on water quality – odour and flavour, colour and turbidity, microbial growth, leaching of metals | Direct effects on water quality – odour and flavour, colour and turbidity, microbial growth, leaching of metals Health risks, usually associated with organic compounds leaching from the product |