By Rick Andrew

The UK has established regulations, requirements and testing of water supply fittings since the 1980s. For the purposes of these regulations and requirements, fittings means any product or assembly including valves, connections, POU or POE products, etc. These requirements were significantly updated in the form of the UK water supply regulations of 1999. These regulations state that no water fitting shall be installed, connected, arranged, or used in such a manner that it causes or is likely to cause waste, misuse, undue consumption, erroneous measurement, or contamination of the water supply. It is these five considerations that drive the testing requirements which are the basis for conformance to the UK water supply regulations of 1999.

Under the regulations, there is a legal duty on all users, owners or occupiers and anyone installing water systems, fittings or appliances to ensure compliance. Advance notice of proposed installations in specific cases must be provided, creating an environment in which architects, building developers and plumbers must follow these regulations on behalf of future owners or occupiers.

Requirements of the UK water supply regulations
There are five key considerations in the UK regulations regarding impact of water supply fittings on the water supply:
1. Waste
2, Misuse
3. Undue consumption
4. Erroneous measurement
5. Contamination

These considerations have led to the development of two general categories of tests:
1. Mechanical tests
2. Material or hygienic tests

Mechanical tests
In the category of mechanical tests, there are four broad categories to consider, as follows:
Waste. Under the UK regulations, waste is considered to be leakage of water. Excess use of water is considered separately. Tests to address waste include evaluations of mechanical strength through porosity, joint effectiveness and closure of valves. There are also tests to assess endurance of operating mechanisms, as well as resistance to thermal cycling.

Misuse. Misuse of water under the UK regulations includes improperly using water for purposes of cooling and uses of water pressure for inappropriate purposes other than the purpose of delivering the water supply.
Undue consumption. Toilet flushing volume, amounts of water used in various cycles of appliance functioning, flowrates of faucets and volumes of water used by washing machines are included under the scope of undue consumption under the UK regulations.
Erroneous measurement. The main consideration under erroneous measurement is the accuracy of water meters.

Material or hygienic tests
There are two main considerations related to material safety, the first of which is a focus on contamination and the second is a requirement to meet British Standard (BS) 6920.

Contamination. Requirements to avoid contamination of the water supply include measures to prevent infiltration of particles and also to prevent backflow. The application of coatings is also evaluated to assure that they are any coatings are not contaminating the water supply. Finally, the potential for corrosion or galvanic action is addressed due to the potential for contamination resulting from any corrosion.

BS 6920. Conformance to BS 6920 is the remaining piece addressing prevention of contamination under the UK regulations. The lengthy official title, Suitability of non-metallic products for use in contact with water intended for human consumption with regard to their effect on the quality of the water, accurately captures the scope and purpose of the standard. There are five main test requirements under BS6920, applied to all non-metallic materials in contact with water:

1. Odor and flavor. This test is performed on individual materials to determine if the materials impart a discernable odor or flavor to the water. The test uses a qualified taste-test panel that evaluates serial dilutions of exposure water.
2. Color and turbidity. Evaluations are conducted on each material to determine whether they increase the color and/or turbidity of water to which they are exposed. Increases in color and turbidity are determined through instrumental analysis methodologies.
3. Extraction of metals. A leaching test on all non-metallic materials is conducted, with analysis of a specified list of metals regardless of material type or formulation.
4. Extraction of substances of concern to public health. This evaluation of gross acute toxicity is achieved using a cytotoxicity approach. After the materials are exposed to water, the water is placed in contact with mammalian cells to observe any toxic effects on the cells. Toxic effects on the cells indicate potential human toxicity.
5. Growth of aquatic microorganisms. Materials are placed into water that is saturated with dissolved oxygen and sealed into bottles with no head space. Over a period of weeks, the dissolved oxygen levels are measured. A decrease in the levels of dissolved oxygen indicates growth of microorganisms.

Note that each of these tests is conducted on individual materials. None of the tests are conducted on complete products, unless the product is made of only one material. So, there are multiple material tests required for products that include multiple non-metallic materials in contact with the water supply. Note also that unlike the NSF/ANSI water standards, no formulation disclosure is required because the testing is applied in the same way for each non-metallic material regardless of material type or formulation.

In fact, there are significant contrasts between the NSF/ANSI water standards and BS 6920. The NSF/ANSI water standards typically involve whole-product testing. The basis for the material safety tests under the NSF/ANSI water standards is contaminant-leaching and toxicological evaluation of any contaminants detected. Material formulations of most materials in contact with drinking water are reviewed to develop a list of potential contaminants the laboratory will analyze. The testing is specific to the materials in the product that are in contact with drinking water. The evaluation of detected contaminants for potential toxicity is based on toxicological assessment procedures described in great detail in the standards. Parameters such as odor and flavor and growth of aquatic microorganisms are not considered with respect to the NSF/ANSI Standards.

Demonstrating conformance
There are multiple avenues for demonstrating conformance to the UK regulations. One of the best known is through Water Regulations Advisory Scheme (WRAS) approvals. WRAS approvals require submittal of product information and test results to demonstrate conformance to the UK regulations. Test results must be from laboratories identified on the WRAS website at WRAS approves these laboratories based on their participation in comparison tests conducted to ensure that approved laboratories achieve similar test results.

Once the information is submitted, it is reviewed by the Product Assessment Advisory Group (PAG). The PAG meets about 20 times each year to review the recently submitted WRAS-approval applications and make a determination regarding acceptance. Note that audits of manufacturing facilities are not required for WRAS approvals. The WRAS approval is issued upon approval by the PAG. The approval is added to the online Products and Materials Directory. This directory can be found at Approvals are valid for five years. Products achieving WRAS approval are authorized to use the scheme’s approved certification mark.

In contrast with WRAS approvals, typical North American certifications do not use an assessment group or committee-type approach for determining conformance. Usually the process of the certification body directly assesses conformance and grants or denies certification. Also, North American certifications require auditing of the manufacturing facility both initially and on an ongoing basis in addition to product documentation and testing as part of the overall certification.

Recognizing the value of manufacturing facility audits, there are other certifications for demonstrating conformance to UK regulations that use the same testing criteria and also incorporate audits. One such program is NSF’s REG4, with a listings directory that can be located at Another is KIWA’s KUKreg4 program, with a listings directory that can be found at

About the author
Rick Andrew is NSF’s Director of Global Business Development–Water Systems. Previously, he served as General Manager of NSF’s Drinking Water Treatment Units (POU/POE), ERS (Protocols) and Biosafety Cabinetry Programs. Andrew has a Bachelor’s Degree in chemistry and an MBA from the University of Michigan. He can be reached at (800) NSF-MARK or email: [email protected]


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