As part of the Water Supply (Water Fittings) Regulations, any fitting has to be compliant when installed to carry or receive water from the public mains water supply in the UK.

Water fittings should not cause waste, misuse, undue consumption, or contamination of the water supply and must be ‘of an appropriate quality and standard’.

Typically, one of three forms of evidence should be used to demonstrate conformity for non-metallic water fittings and/or their component parts.

These are:

1. Secretary of State Approval
2. Non-metallic component certification
3. BS 6920 test reports

To find out more about how to demonstrate compliance with Regulation 4, take a look at this article from the WRAS website: https://www.wrasapprovals.co.uk/news/articles/compliance1/

Backflow is a term in plumbing for an unwanted flow of water in the reverse direction.

Backflow can be a serious health risk if the main water supply comes into contact with foul, stagnant or contaminated water.

Our team of inspectors categorise the risk of contamination of the public water supply from backflow of any fluid.

Fluids are risk categorised from Fluid Category 1 (mains drinking water) to Fluid Category 5 (significant risk to health).

As the contamination risk through the fluid categories increases, a more stringent backflow prevention device is required to protect the water network. Mechanical devices can fail and allow backflow. Fluid Category 5 risks require a physical air gap to remove the risk altogether.

Fluid 1

Fluid 1 is water that is supplied by a water company. No prevention devices are needed. 

Fluid 2

Fluid 2 is water with a slight change of temperature, taste or odour, but does not pose a health risk. Examples include water from a water softener, and water from an ice machine. A single check valve would be required to prevent backflow. 

Fluid 3

Fluid 3 is fluid which represents a slight health risk. This includes:

• Water in domestic washing machines and dishwashers
• Water in domestic heating systems
• Washbasins, baths and showers
• Water used for air conditioning units

Double check valves would be required to allow water to flow in one direction, but close if water starts to flow backwards. 

Fluid 4

Fluid 4 is fluid which represents a significant health risk. This includes:

• Dairies
• Food preparation
• Commercial heating systems
• Fire sprinkler system using anti-freeze solutions
  

Reduced Pressure Zone (RPZ) valves would be needed to stop backflow.

Fluid 5

Fluid 5 is fluid which represents a serious health risk. This includes:

• Water in kitchen sinks, toilets and bidet showers next to a water closet (a flushing toilet)
• Sewage treatment
• Medical waste
• Water for agricultural use
• Greywater recycling
  

Air gaps between the inlet and outlet using type AA, AB or equivalent would be required as a prevention device. 

RPZ valves, also known as type BA Devices, are mechanical devices that provide backflow protection against Fluid Category 4, fluid which represents significant health risks.

RPZ valves are specifically engineered to protect water supplies from contamination caused by substances that pose a significant health hazard. These include chemicals, pesticides, and other toxic materials.

Consent for the installation or removal of an RPZ valve must be granted before work begins.

All valves must be tested annually, and a copy of the certificate should be sent to our water regulations team. 

Many water supplies used on construction sites are intended to remain in place for more than one month, for example, those serving welfare facilities, canteens, or food preparation areas.

To ensure the safety of everyone on site, these fittings must comply with the full requirements of the Water Supply (Water Fittings) Regulations 1999 and should be installed as if permanent.

However, temporary non-domestic water supplies, such as those used for site testing, cleaning, or other short-term construction needs, can, in certain cases, be exempt from the Regulations.

• This exemption only applies where all three of the following conditions are met:
• The supply is metered
• The supply is used for no longer than one month, or for up to three months with written permission from the water company
• The setup is designed so that water cannot flow back through the meter into the company’s main supply (i.e. suitable backflow protection is in place)
  

When the temporary period ends, the supply must either be removed or converted to a permanent connection through the proper application process.  

We recommend choosing a local WaterSafe-approved plumber for any plumbing work.

WaterSafe is a free online directory that helps you find reliable, registered plumbing professionals in your area. Choosing a qualified WaterSafe-approved plumber ensures high-quality work that meets Water Fittings Regulations, protecting your drinking water from contamination and costly mistakes.

We have a legal duty to ensure the water within our network stays wholesome to protect customers’ health.

We provide advice and guidance on regulation, carry out inspections of new and existing premises and enforce the regulations by inspecting a range of plumbing installations.

Anyone found to contravene these regulations can face prosecution.

• Main point of entry – make sure the stop tap and drain tap are easy to access and working. This helps you turn off water quickly and reduces waste.
• Fridge/freezer with water connection – fit a single check valve to stop water from flowing back into your drinking supply.
• Washing machines/dishwashers – these should have a double check valve to prevent stale water from re-entering your home’s supply.
• Garden taps – install a service valve and a double check valve inside the building. This stops contaminated water from getting back into your drinking water.
• Toilet cisterns – make sure there’s a service valve so repairs are easier and water isn’t wasted.
• Boiler filling loops – disconnect these once your heating system is commissioned, unless they’re WRAS-approved. This prevents heating water from mixing with drinking water.
• Showerheads – they should never dip below the bath or basin water level. If they do, fit double check valves on both hot and cold supplies. Never let a showerhead reach into a toilet pan. As a tip, a shorter hose or hose restrictor can be a cheaper way to prevent the showerhead from dipping below the spill-over level.
• Alternative water supplies (rainwater, grey water, boreholes) – any mains back-up must have an AA or AB air gap to keep harmful water out of your drinking supply.