Approved products for use in the UK's public water supply

A list of the products approved for use in contact with drinking water in the UK.


The products in this list have only been assessed for safety for use in public water supplies by water undertakers and licensees. They have neither been assessed for fitness for purpose, nor for use in buildings, nor approved for use in buildings; the Water Regulations Advisory Scheme ( WRAS) operates a specific approval scheme for products used in buildings -

Section 69 of the Water Industry Act 1991, as amended by the Water Act 2003, gave the Secretary of State for the Environment, Food and Rural Affairs and the National Assembly for Wales powers to make regulations controlling substances, processes and/or products that are used in the treatment and provision of public water supplies. Section 76B of the Water (Scotland) Act 1980 gives Scottish Ministers similar powers.

The following Regulations apply to the approval of substances and products used in the provision of public water supplies in the United Kingdom:

a) England - Regulation 31 of The Water Supply (Water Quality) Regulations 2000 (Statutory Instruments 2000 No 3184) -
b) Wales - Regulation 31 of The Water Supply (Water Quality) Regulations 2001 (Welsh Statutory Instrument 2001 No 3911 (W.323) -
c) Scotland - Regulation 27 of The Water Supply (Water Quality) (Scotland) Regulations 2001 -
d) Northern Ireland - Regulation 30 of The Water Supply (Water Quality Regulations) (Northern Ireland) 2007 (Statutory Rules of Northern Ireland 2007 No.147) -

These regulations concern the introduction of substances and products (including construction products) and processes for use in the treatment and provision of public water supplies. They implement the requirements of Article 10 of the European Union Directive 98/83/EC on the quality of water intended for human consumption, in respect to substances and materials used in the preparation and distribution of water up to the point of delivery to premises. They do not transpose the requirements of the Directive with regard to the premises (water supply systems within buildings). In England and Wales these requirements are dealt with by the water industry Water Regulations Advisory Scheme ( WRAS) under the Water Supply (Water Fittings) Regulations 1999.In Scotland there are dealt with by Scottish Water's Water Byelaws 2004.

Under these Regulations water undertakers 1 shall not apply or introduce any substance or product into public water supplies unless one of the requirements of this regulation is met. One of these requirements is that the substance or product has been approved by the Secretary of State for the Environment, Food and Rural Affairs, the National Assembly for Wales, the Northern Ireland Assembly and Scottish Ministers (collectively referred to as the Authorities).

The Regulations provide that the UK Authorities may, by notice given in writing, require any water undertaker 1 to apply for the approval of the use of any process. Processes coming under these requirements are NOT included in this publication. The Drinking Water Inspectorate ( DWI) operates the approval system on behalf of the Authorities. DWI accepts 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 Approval Process

An approvals Committee was originally established in 1966 by the (then) Ministry of Housing and Local Government. The Committee's original terms of reference were to consider whether chemicals used in the treatment of public water supplies might present any risk to the health of consumers. The remit was extended to include construction products used in contact with public water supplies. The Committee advised DWI (acting for the Authorities) on approvals under previous Regulations.

The Committee, renamed the Committee on Products and Processes for use in Public Water Supplies ( CPP), was set up as an advisory Non-Departmental Public Body ( NDPB) in May 1998 and has provided advice, until April 2007, to the UK Authorities under the current regulations.

Applications for approval are now dealt with by the DWI - see Advice Sheet 1

When assessing applications for approval, DWI relies on the expertise of its Inspectors and expert advisers who are experienced in toxicology, chemistry, engineering, water treatment, water distribution and public health.

Basis of approval

When considering an application for approval, DWI considers only whether the use of a substance or product will adversely affect the quality of the water supplied, or cause a risk to the health of consumers. The DWI does not assess fitness for purpose and approval by the Authorities must not be taken as a favourable assessment of the performance or merits of any substance or product.

Applications are considered for all construction products used in contact with water in water treatment processes, water supply pipelines (including raw water pipelines) and drinking and raw water storage installations. In addition DWI considers water treatment chemicals and filtration media that are not covered by a published BSEN standard 2; products (individual chemicals or filter media) that conform to a BSEN standard may be used without the approval of the Authorities in accordance with any appropriate additional National conditions of use.

It is important to note that approval of products does not give any indication as to the effectiveness or merits of the products in relation to any use.

Approved products have not been assessed for suitability for use with regeneration chemicals used in association with some water treatment processes; for such use, specific testing after exposure to the appropriate aggressive chemicals should be undertaken.

DWI cannot advise on approval of products that will not be placed on the United Kingdom market.

Products Approved Under Previous Regulations3

Approvals given under what are revoked Regulations are continued in effect by the combination of sections 17(2)(b) and 23 of the Interpretation Act 1978. So far as relevant, the effect of those provisions is that anything (including the approval of a substance or product) done under the previous Regulations that could have been done under present Regulations is taken to have been done under the latter Regulations. For advice on Natural or Traditional products please refer to Advice Sheet 10 -

Review of Approved Products

New toxicological information - From time to time the DWI is made aware of new toxicological information on specific substances, usually from other recognised national or international bodies. DWI will review this information, and where necessary seek expert toxicological advice concerning the impact of this data on currently approved products containing those substances. If it is found that this information indicates that some approved products could pose a potential risk to human health, DWI may require some retesting of them. This process is set out in Advice Sheet 1, Section 7.2 and 9.2 -

Changes to approved products - Approval holders are advised to keep changes to a minimum, but it is recognised that sometimes changes are necessary. If the approval holder makes any change to an approved product, this must be notified to DWI as soon as possible so that an assessment of the implications of the change can be made. Major changes may mean that DWI will require further information or testing to determine whether the approval of the product can be maintained. It is for DWI to assess the significance of the change; some minor changes may require no further action. Further details are given in Advice Sheet 4 -

In some cases either of the above could lead to revocation of approval of the product.

Breaches of any condition of approval would be grounds for revocation of that approval.

The Annual List of Approved Products

The relevant Regulations require that a list of all the substances and products approved or refused and all approvals revoked or modified, shall be published, at least once a year.

This list is regularly updated by DWI throughout the year, and includes details of changes to approved products and additions to the List. The list is posted on the DWI website: A list is published annually by the Scottish Government on their website :

Please see the DWI website for the most up-to-date list. Printed copies of this list may not be up-to-date.


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