How many stopcocks does a home need and of what type?

When there is a leak or an appliance has to be repaired, the difference between shutting off the water to the whole home or just that one point comes down to how many stopcocks were fitted and where. It is one of the cheapest items in a plumbing installation and one of the most missed when absent.

Four types of valve, four different functions

• Stopcock (gate/isolation valve): shuts off the supply to a given section or appliance without affecting the rest of the installation. Always fit an accessible main stopcock at the entrance to the home, and an individual one under each appliance (washbasin, WC, washing machine) so it can be repaired without cutting the water to the whole house. Usual diameters: 1/2″ (15 mm), 3/4″ (20 mm), 1″ (25 mm) and 1″1/4 (32 mm).
• Angle valve: an individual shut-off valve at a 90° angle, the most usual for connecting washbasins, WCs and bidets to the concealed pipework. It is fitted straight onto the outlet coming out of the wall, so it's wise to always leave a small access hatch or decorative escutcheon that lets it be operated without breaking out the tiling.
• Ball valve: a quarter-turn shut-off valve (opens/closes by turning 90°), very reliable and quick to operate. Unlike the classic spindle stopcock, it doesn't seize up over time and gives a total shut-off even after years of not being used — the recommended option for hard-to-reach main valves.
• Non-return valve: lets water pass in one direction only, preventing backflow that could contaminate the network or damage equipment. It is mandatory at the outlet of pressure booster sets, after the main meter and at the connection of heat pumps or water softeners.

Where to put each one

The home's main valve, easy to reach, can be a ball valve if it sits in a rarely visited spot (it may go years without being operated). Under each sanitary appliance, the angle valve is the standard option because of its direct connection to the concealed outlet. The non-return valve is reserved for points where water must not flow backwards: meter, pressure booster sets, water softeners.

Frequently asked questions

Is it mandatory to fit a stopcock under each appliance? It isn't mandatory by regulation, but it is the recommended practice: it lets a specific appliance be repaired without cutting the water to the whole home.

What's the difference between an ordinary stopcock and a ball valve? The ball valve doesn't seize with time and gives a total shut-off even after years unused, whereas the classic spindle one can end up seized on valves that are rarely used.

Where is the non-return valve mandatory? At the outlet of pressure booster sets, after the main meter and at the connection of heat pumps or water softeners.

Conclusion

Distributing the types of valve well according to their function —ball valve for the main, angle valves for individual appliances, non-return where regulations require— is one of the cheapest decisions with the most real impact in a plumbing installation. Quoting them all, not just the main valve, stops a small fault forcing the water to be cut to the whole home.