Regulation 31 (formerly Regulation 25) of the Water Supply (Water Quality) Regulations sets out conditions under which a Water undertaker in England and Wales may apply products to water to be supplied for drinking, washing, cooking or food production.

Regulation 31, with certain limited exceptions, requires that only products that have been approved by the Secretary of State for the Environment, Food & Rural Affairs may be applied or introduced into water that is to be supplied for domestic purposes or food production. The Drinking Water Inspectorate (DWI) is the government body responsible for ensuring that water undertakers in England and Wales comply with the Regulations and failure to comply with these regulations may result in criminal prosecution. Scotland and Northern Ireland follow a similar process.

WRc-NSF is a designated Laboratory to carry out leaching tests specified by DWI in support of an application for Regulation 31 Approval.

Applications for approvals under Regulation 31 are assessed by the DWI, taking into account, amongst other things, the results of leaching tests and toxicological issues. One of the main focuses of the assessment is the potential for a product to release harmful organic substances into the public water supplies, a serious concern which is not fully addressed in the WRAS tests (BS 6920).

Initially the DWI requests extensive information on the product, including:

	its intended use and application, including confirmation of its use by a water undertaker in England and/or Wales;
	instructions for use;
	the complete composition of each component that comes into contact with water including all relevant Material Safety Data Sheets (MSDS) for these; and
	BS 6920 tests may also be required on individual non-metallic components.

From this data the DWI identifies those chemicals that might be released from the product, and specifies leaching tests to monitor the extent to which they are released. The tests involve preparing sample of the product in accordance with manufacturer's instructions and then leaving fresh test water to stand in contact with the samples under defined conditions. The water is analysed after each leaching period for leaching substances.

Leachates will also be subjected to GCMS general survey to identify any significant leaching of unexpected chemicals and to Total Organic Carbon (TOC) analysis.

Then the DWI considers whether the test work has been carried out correctly and if the leaching observed is acceptable on a toxicological basis. More data may be required from the applicant. Finally the DWI, if satisfied that the use of the product would not have adverse effects on water quality and would not pose unacceptable health risks to consumers, makes a recommendation to the Secretary of State that the product can be approved under Regulation 31, subject to appropriate conditions. The DWI then issues an approval letter. The DWI in conjunction with the Drinking Water Quality Regulator in Scotland and the Environment an Heritage Service in Northern Ireland also produces an annual list of approved products. The List of Approved Products is available on the DWI's web site.

Help from WRc-NSF

Gaining approval for use of a product under Regulation 31 can be a lengthy, time-consuming and expensive process. Often these problems can be reduced by contacting WRc-NSF during product development, who will act as a consultant.

At the start of the approvals process the manufacturer makes an application to the DWI with information on the composition and use of the product, backed by appropriate BS 6920 test reports . WRc-NSF can help at this stage, collecting and collating confidential information from suppliers. The DWI may then request other information which WRc-NSF can collect and present on the applicant's behalf.

WRc-NSF has many years of experience helping manufacturers and suppliers gain DWI approval, our experience includes:

	Assessment of leaching of substances from materials, using both static and dynamic laboratory tests and field trials on a large range of materials including: plastic pipes; pipe renovation materials; membrane filtration systems; linings; coatings; sealants; activated carbons etc.
	Design of appropriate leaching tests for different products.
	Development of analytical methods suitable for monitoring materials leaching from products (to the stringent requirements of the DWI).
	Pioneering work in the identification of unknown contaminants using general survey gas chromatography mass spectroscopy (GCMS).
	Participation in the development of methods for teting product's effects on taste and odour.
	Expert chemical safety assessments from WRc's toxicologists.

Steps to Gaining Approval

The following steps are required to gain Regulation 31 Approval. Please contact WRc-NSF for further information and guidance on the application process.

1.	Download instructions and Application Forms from the DWI website.
2.	Collate application information including:
	a)	BS6920 reports for all water contact non-metallic components (WRc-NSF can carry out these tests)
	b)	The chemical formulation of all water contact components, including all relevant Material Safety Data Sheets (this data is normally obtained from suppliers)
	c)	Instructions for use
3.	Application sent to the DWI for initial review.
4.	Application considered by the DWI and leaching test specifications agreed.
5.	Analytical methods confirmed, leaching tests carried out and results reported.
6.	Assessment of the report and toxicological assessment of the leaching test results by the DWI.
7.	Approval issued or refused or further information requested.

For further information please contact Peter Jackson.

Last Updated: 04 January 2010

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