Water fittings regulations

The Water Supply (Water Fittings) Regulations 1999 govern the installation and maintenance of water fittings in any premises which are connected, or are to be connected, to a public water supply.

The regulations do not apply to premises which only have a private source of water, although they do provide a useful code of practice for private supplies.

The regulations protect public health and promote sensible and efficient use of water by placing legal duties on the installers of water systems and owners and occupiers of premises.

We have some important information in relation to double check valves (DCV) for internal domestic appliances such as dishwashers and washing machines, to share with you.


In April 2017, the Water Regulations Advisory Scheme (WRAS) released an amendment in relation to installation requirements under the Water Supply (Water Fittings) Regulations 1999 in England and Wales which now means these appliances will need an additional DCV installed at the point of connection between the water supply and the appliance.


IRN 160:
“A compliant double check valve or some other no less effective device providing backflow prevention protection to at least fluid category three shall be fitted at the point of connection(s) between the water supply and the fitting or appliance. Where the double check valve is for use with products that incorporate water injected with CO2 gas all metal parts in contact with the water passing through it must be constructed from chrome nickel stainless steel.”


IRN 360:
“Domestic unvented primary circuits may be filled or replenished by means of a temporary connection between the primary circuit and the supply pipe. An ‘Approved’ double check valve shall be installed at the point of connection to the supply pipe. A permanent connection between the primary circuit and the supply pipe may be made via a CA backflow prevention device or some other no less effective backflow prevention device.”


Historically, an assumption was made that all domestic appliances were fitted with double check valves and internal inspections would have passed.


Our Customer Services Representative team will now fail all domestic internal inspections where appliances such as washing machines, washer-dryers and dishwashers where the fitting is not present.


If you have any questions in relation to this subject, please refer to our helpful guide ‘Water Regulations for Domestic Properties’.


Our quick guide to water fittings regulations

Our guide to the water fittings regulation


Does your property comply with the water fittings regulations?

Be safe, be WaterSafe - Information leaflet produced by WaterSafe

Planning some plumbing work? (pdf, 0.90MB)

Information guide for your home (pdf, 1.21MB)

Information guide for businesses (pdf, 1.31MB)

Information guide for farm and agricultural buildings (pdf, 1.61MB)

Information guide for hotels and catering outlets (pdf, 2.20MB)

Rainwater harvesting (pdf, 0.50MB)


Where can I get a full copy of the water fittings regulations? 

See WRAS website for more detailed information.

RPZ valves - commissioning and site testing of Type BA Device

  • Commissioning and site testing of a Type BA Device (Reduced Pressure Zone valve) assembly must be carried out by a City & Guilds accredited tester who has been approved by the water supplier as competent to test Type BA Devices
  • Testing must be carried out at intervals not exceeding 12 months
  • On completion of a site test, a test report certificate must be completed by the tester with copies submitted to the water supplier and the person responsible for the device
  • Please note, Type BA Devices will only give backflow protection up to fluid category 4.

Fitting an RPZ valve (type BA device)

Apply for consent to install an RPZ valve (type BA device)

Contact an accredited Type BA Device tester

Design consideration for water supplies in apartment buildings and flats

This guide is to help developers and installers when designing water service layouts in multi occupancy buildings such as maisonettes, apartment blocks and flats. 

Building regulations - Part G

Understand more about the key points to be aware of with the Part G of the building regulations guidance document 

Need help or want further information?

Call: 0345 60 66 087 Option 4, then option 2 (08:00 to 17:00 Monday to Friday) 
Email: reg5@anglianwater.co.uk