KIWA and UK Water Regulations

We take a look at the regulations covering water systems and how the KIWA mark can assure you of compliance.

Which regulations cover water systems and components?

All component products installed on water systems in all premises in the UK must comply with UK water regulations[1] (specifically the Water Supply (Water Fittings) Regulations 1999 for England and Wales, the Water Bylaws 2000, the Water Supply (Water Fittings) (Scotland) Byelaws 2014 and the Water Supply (Water Fittings Regulations (Northern Ireland) 2009)) and in particular Regulation 4 which lays out the specific requirements for the components which make up a water system. If you install component products on the system that are not documented as being compliant then you are causing an offence and could be prosecuted.

It's not an offence to manufacture non-compliant components, rather the duty lies with the installer to ensure that every product component connected to water supply or management will meet the relevant regulations.

Therefore, it's in the interest of all professional manufacturers of water system components – such as ACV – to ensure that all products are certified to meet the requirements laid out within Regulation 4 of the Water Supply (Water Fittings) Regulations.


What tests must a product pass to be certified as meeting regulations?

To confirm that a product can be certified, a product must be mechanically tested to the relevant British and harmonised European standards.

All the materials used in the manufacture of component products must meet the requirements of BS 6920 ‘Suitability of non-metallic materials and products for use in contact with water intended for human consumption, with regards to their effect on the quality of the water’. This states that all non-metallic materials which come into contact with water intended for domestic use must conform to the requirements of BS 6920. This includes a number of tests to assess the suitability of non-metallic materials to ensure they do not impart odour or flavour, cause a change in appearance (colour or turbidity), promote microbial growth, or leach substances (including toxic metals) harmful to human health.

Which certification will tell me that a product has passed the relevant tests?

Once component products have been fully tested, they can then be certified in the UK for the manufacturer. Traditionally, tested products would have been looking to achieve Water Regulations Advisory Scheme (WRAS) approval.

Today there is a choice of three approval schemes: WRAS, KIWA or NSF.

 All three schemes must use the same testing processes and standards to demonstrate compliance, and so can be considered to be equal to each other. Each of these approval schemes provide evidence of full product component compliance with the individual requirements of Regulation 4 of the Water Supply (Water Fittings) Regulations.

All Water Boards in the UK will allow you to install a product that is certified under any one of the above-named approval schemes. The quality marks of each organisation tell the user that the component or material has been thoroughly tested and is passed as suitable for  installation onto water systems.

 ACV uses the Kiwa approval scheme to demonstrate compliance for their WaterMaster water heaters, HeatMaster combined boilers and water heaters, E Tech S electric boilers with hot water storage, and the Smart range of hot water storage cylinders.

What is KIWA?

KIWA is an international certification, inspection, testing, and training company and Kiwa Watertec specialise in testing water products and components to be certified as safe to install within water supplied for domestic or food production purposes.

 The Kiwa UK Regulation 4 Product Approval Scheme (KUKreg4) is a robust process for demonstrating compliance with the UK Water Supply (Water Fittings) Regulations 1999.  Once a product, or set of products, has passed assessment by Kiwa they can then be certified as approved as meeting these regulations.

 KIWA certified products will display this mark and will be added to the Kiwa UK Regulation 4 approved product list which is accessible online:

KIWA proves compliance with UK Water Regulations

How does Kiwa KUKreg4 work?

The KIWA approval scheme is for all manufacturers and distributors of plumbing products used in the supply of water within the UK. The KUKreg4 scheme covers products across a wide range of plumbing uses including sanitary tapware pipes and fittings, valves, appliances, catering equipment, and WCs. All testing is carried out in Kiwa laboratories which are themselves ISO/IEC 17025 accredited by UKAS, RVA, Accredia.

Once the product has gained accreditation through testing and verification by Kiwa experts, it can be regularly reviewed to maintain compliance should regulations change.

David Jay from Kiwa Watertech [2] says "For most products, the current CE mark won’t satisfy regulations. You must ensure your products comply. Product approval or certification is not actually a legal requirement laid out in the regulations but, as an installer, you need to be able to demonstrate during the regulation enforcement process how your product complies."

The water undertaker/supplier has the legal right to enforce regulations and installers could be faced with a delay in water connection or even a demand to remove any installed products from existing connections should they not be able to provide evidence that a component product is sufficiently compliant. Having a recognised accreditation mark such as the KUKreg4 – and being able to find and verify any product bearing the mark or claiming to be accredited on the KUKreg4 database – can actually fast track the water company approval of installations.


You can search for approved products by manufacturer name, approval number or keyword on the KIWA website:


Is WRAS also a mandatory requirement?

Our customers sometimes ask for the WRAS approval for our products - or WRAS is stated in the project specification - as this is historically the most widely known approval scheme.

 The KIWA KUKreg4 approval mark demonstrates full compliance with the UK Water Supply (Water Fittings) Regulations 1999, exactly like WRAS does, and so can be universally accepted as equal to WRAS approval.

We are now starting to see the changing text within project specifications from ‘WRAS approval required’ to ‘Evidence of Regulation 4 Compliance required’. This change in wording acknowledges that the approval schemes have equal merit in demonstrating component product compliance.

 The KIWA mark demonstrates that our products have undergone a robust, independent evaluation by a well-respected, independent, international testing, inspection, and compliance (TIC) company. 

Which ACV component products are KIWA approved?

The following ACV products carry the KUKReg4 certification:

Smart E/Smart E Plus 1607715

Smart L/Smart Green/ Smart E 1607716

Smart ME 1607717

E-Tech S 1607719

HRs 1607720

HeatMaster 1609700

WaterMaster 1609739

 Look out for the KIWA logo on the product pages.

When you come to ACV you can always be assured of excellence in hot water.