22mm double check valves are designed to protect potable water supplies from contamination by preventing backflow. These valves feature two internal check mechanisms that work in series, ensuring that if one fails, the other provides a secondary barrier — making them a crucial part of safe plumbing systems.Commonly installed on incoming mains water lines, outdoor taps, or supply lines to appliances, double check valves are required in many scenarios to meet water regulations. Compact, easy to install, and compatible with standard 22mm pipework, these valves are a simple yet effective way to maintain hygiene and system integrity.

Key features and benefits of these valves.

Key Features

Features two spring-loaded internal check mechanisms for enhanced safety. Even if one fails, the second prevents reverse flow.

Key Features

Designed for 22mm pipework with compression ends for a quick, secure connection. Fits neatly into tight spaces under sinks or in service boxes.

Key Features

Meets UK water regulations for use in drinking water systems. Essential for outdoor taps, washing machines, and combi boiler feeds.

Backflow from a contaminated source can pose serious health risks, especially when it enters a clean water supply. 22mm double check valves are vital for preventing this, offering two layers of defence against reverse flow that could allow dirty water, chemicals, or bacteria into your mains water. They are often a regulatory requirement, especially when connecting appliances or garden taps to a domestic supply.

These valves are not just a compliance tool — they’re a proactive way to protect your system, maintain water quality, and ensure peace of mind. Whether you’re a homeowner or a professional installer, a double check valve is an essential addition in the right application.

You’ll commonly find 22mm double check valves fitted:

On outdoor garden taps
Before washing machines or dishwashers
On mains-fed combination boilers
In commercial kitchens or washdown stations
Near unvented cylinders or cold water storage tanks

It’s designed to prevent backflow in plumbing systems by allowing water to flow in one direction only, protecting the mains water supply from contamination.

It refers to two internal check mechanisms that act as a backup to each other, offering enhanced protection against backflow compared to a single check valve.

Typically on the cold water feed to appliances like dishwashers, outside taps, or water heaters — anywhere backflow prevention is required.

Yes, in many applications, especially those connected to the mains water supply. UK water regulations often require them for external taps and certain appliances.

Generally, they are used on cold water lines, but some models are suitable for hot water — always check temperature ratings before installation.

There may be a slight drop in pressure due to the internal mechanisms, but a well-designed 22mm double check valve will keep this minimal.

Yes, many 22mm double check valves are WRAS approved, meaning they’re safe for use with potable (drinking) water in the UK.

They’re usually maintenance-free, but it’s good practice to inspect them during regular system checks, especially in hard water areas where scale can build up.

Yes, most models can be installed in either orientation — just ensure the flow direction follows the arrow marked on the valve.

They’re designed for use with 22mm copper or plastic pipework and typically feature compression fittings for easy installation.

Yes — fitting a 22mm double check valve on an outdoor tap prevents contaminated water from hoses or attachments flowing back into the clean water supply.

With correct installation and use, they can last for many years. Lifespan may vary depending on water quality and system conditions.

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