Water regulation advice and guidance

Poor plumbing may cause very serious problems, such as harm to health, and could lead to poor water quality.

Since 1999, the regulations have been in place. Before that, there was the water regulation byelaws (or ‘the byelaws’). Any plumbing systems or fittings installed after 1999 have to follow the regulations, anything installed before date falls under the byelaws that were in place at that time.

Who is included in the regulations?

All customers who have drinking water from us, or need a drinking water supply, as well as any plumbers and installers involved, may need to know about the regulations.

Building owners and occupiers, developers, designers and architects, may also need to know about the regulations. Even customers who have their own private water supply (e.g. they get drinking water from their own well / borehole) may need to know, if they are also connected to, or are planning to become connected to, the drinking water we supply.

What is included in the regulations?

The regulations explain how to design, fit and look after plumbing systems and fittings. They have our safety in mind, and want to protect us against problems such as:

  • Contamination (e.g. nasty chemicals in drinking water);
  • Waste (e.g. plumbing systems that leak); and,
  • Misuse; undue consumption; and, erroneous measurements (e.g. water meters installed in the wrong places, or people illegally using the drinking water supply).

Protecting customers against contamination entering the drinking water supply is one of our biggest concerns. When visiting customers, we undertake a risk assessment, to help find the problems and work out how they can be fixed.

Our Water Regulations Team

Welsh Water have a water regulations team who manage compliance with the regulations.

Our water regulation officers undertake inspections of premises with new connections and also existing connections. They will:

  • Inspect your plumbing system / installation
  • Assess the hazards and so the level of risk posed at a premises
  • Identify any non-compliances against the regulations
  • Recommend what protection measures need to be implemented to address the non-compliance.

If any non-compliances against the regulations are identified, they need to be rectified as soon as practicable. Depending on the seriousness of the non-compliance, our actions may range from the immediate shutoff or disconnection of water supply to a customer, through to issuing a 28 day notice for the customer to rectify the non-compliance, through to potential prosecutions.

Our customer enforcement policy can be found below. (You can find the Welsh version of our policy here.)

It is the customer’s responsibility to carry out any work necessary to comply with the regulations. However there are other circumstances where responsibility may not lie with the customer. This will be explained in more detail by the water regulations officer at the time.

We cannot provide guidance or support on disputes with your installer, but we can provide advice on the interpretation of the water regulations. You can contact our regulations team at WaterRegulations@dwrcymru.com.


The Water Industry Approved Plumbers’ Scheme (WIAPS) is run by Water Regs UK on behalf of a number of water companies.

This is one of the seven existing approved contractors’ schemes in the UK. Their website website provides a list of ground workers who are qualified to undertake work on outside water services only and other specialist workers who work within designated sectors.

It should be noted that in terms of plumbing fixtures, fittings and appliances, it is not illegal to sell unsuitable items, but depending how they are used in plumbing and installations, that could be deemed illegal. An approved plumber or company should be aware of this and actively consulting the Water Regs UK website for this information to ensure the correct fittings and materials are being used and installed as prescribed.

Suitable fittings and materials are shown on the Water Regs UK website (also see the ‘General Information and Advice’ Section) which cover their properties and installation details. 

Water Regs UK

Water Regs UK is the UK’s central body that facilitates compliance with the water supply (water fittings) regulations, and all the UK’s water suppliers subscribe to it.

Water Regs UK provides a wealth of information, contacts and publications through its website. They provide a current list of approved manufacturers products and materials, and installation methods for use in plumbing systems and installations.

Water Regs UK can also provide guidance to enquiries regarding the interpretation of the regulations, and information on how disputes could be resolved between customers and relevant parties involved in plumbing systems. This includes for a small cost, a comprehensive water regulation guide which includes the water fittings regulations and the regulators guidance clauses.

Water Regs UK’ address is:
Unit 13, Willow Road,
Pen-y-fan Industrial Estate, Crumlin,
Gwent, NP11 4EG,
Telephone: 03332 079 030

As part of compliance with Water Regs UK latest policy, all water companies are to produce a customer enforcement policy outlining how the regulations will be enforced, shown below.

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Water Regulations Enforcement Policy

PDF, 318.5kB

Private Water Supply leaflet

227.4kB, PDF

Water Regulations General Advice

435.7kB, PDF

Water Regulations Infringement Handout

84.7kB, PDF

Water Regulations - Information for Developers, Designers and Installers

646kB, PDF

Water Regulations Agricultural Guidance

1.1MB, PDF

Water Regulations - how they affect your business

346.2kB, PDF