Notification and testing of works

If you need a new water supply, or are changing any plumbing that relates to the water regulations, we want to be notified to ensure it complies with the regulations.

Planning any plumbing work?

Welsh Water encourages the use of WaterSafe Approved Plumbers to all our customers. WaterSafe members are qualified professionals who have demonstrated a knowledge of the Regulations and have the necessary levels of insurance for the work they carry out. They will provide you with a certificate when the job is completed to state that it complies to these Regulations. We are required to be notified before certain works start, so the WaterSafe member will provide us with the relevant information to make sure the installation is safe and compliant. Head to to find out more 

Visit the WaterSafe site

Welsh Water have a ‘Developer Services Team’, who can tell you about connecting your home or business to our drinking water supply and waste water pipes. They receive requests and plans for new connections all the time, and can discuss whether our network can deal with your new connection without any problems, or whether you may need to change your plans a little bit. The Developer Services Team have an online application form to complete at the following link.

Notifying us of changes

If you want to make the following changes to plumbing systems or fittings, please sent us a ‘notification of proposed installation form’:

  1. The extension or alteration of a water system on any premises other than a house;
  2. A material change of use of any premises; and,
  3. The installation of a number of fittings listed in the Notification Form.

The form has a link to a guidance section, but please also note that:

  • We need to have your notification form before you start or have installed any plumbing system or water fittings described in the form, and or in the text above. We will aim to send a response to you within 10 working days of us receiving your notification form.
  • If you haven’t had a response from us, and it’s been longer than 10 working days, this means we have approved the application. This still means that the plumbing work has to be completed in the right way, and pass the regulations.
  • The law allows us to take legal action if we are not notified.

If you disagree with any conditions of consent, or feel consent has been withheld unreasonably, you may consider taking the matter to Arbitration as per Regulation 13 of the Water Supply (Water Fittings) Regulations 1999, a copy of which can be found here.

Notification of Reduced Pressure Zone Valve Installation Form

If you wanted to protect your drinking water supply, from hazards that are up to a fluid category 4 (see ‘General Information and Advice’ section), you could have a reduced pressure zone valve, or RPZ, installed. RPZ valves help protect drinking water supplies from chemicals or contaminants that could cause a health hazard (e.g. pesticides or biological organisms).

The Water Regulations Advisory Scheme have a leaflet ((an ‘approved installation method’ (or AIM)) here, which explains the installation, maintenance and testing of RPZ valves, as well training requirements for the tester.

If you want to install an RPZ valve, there is a ‘notification form’ to complete. This can be obtained by:

  • Downloading the form here, and emailing it to our address, including any relevant plans.
  • Downloading the form and posting it, including any relevant plans, to: FAO Water Regulations Team, Dwr Cymru - Welsh Water, Players Industrial Estate, Clydach, Swansea, SA6 5BQ

The ‘notification of RPZ installation form’ has a guidance section at its base, but please also note that:

  • All RPZ valves must be tested at least annually, and will be recorded on DCWW’s records.
  • More guidance can be found on Water Regulations Advisory Scheme website at the following link.

Testing of RPZ Valves

The commissioning and compliance testing of RPZ Valves must be undertaken by someone who is competent and qualified to do so. You can find accredited RPZ valve testers on the WaterSafe website by visiting watersafe

All commissioning and compliance test certificates should be sent to Welsh Water within 10 working days of the testing being completed. Certificates should be sent to:

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Notification of proposed installation

PDF, 127.9kB

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Notification of RPZ Installation form

PDF, 73.4kB