Stopcock

No motor required

Brilliant. I have sent this to my brother.

Friend of mine had one of them. Rather amusingly, when they did have a flood, it was caused by the motorised stopcock leaking. Not letting by. Leaking in its own right.

Also, the possibility of a flood tripping an RCD doesn't seem that remote to me.....

Like all remote possibilities, they are triggered by the need to rely on them not happening.

You can get automatic shut-off valves which stop the supply if they detect a leak. There are different types, which can either measure water flow, use water leak detectors, placed around the home, or use ultrasonic leak detection.

I've had a Surestop for more than 30 years to isolate the pipe run to my outside taps and although they are only operated around twice a year have proved reliable*. They turn of instantly if there is enough water flow. It will not close if there is zero or just a dribble flow through the pipe at the point of flicking the switch. I close the valve and then open a tap at which point it fully closes down with a soft thud. At this point any flow is fully stopped. This means that you have to get used to not just flicking the switch when leaving for a winter holiday and assuming it will be closed for when you have a minor pipe burst. You should also turn on a tap to get it to close down.

The one in my garden is well stuck so there is another under the stairs and according to Thames Water it can be turned off at the meter in the road. Brian