A broken stopcock behind a bathroom panel, changed with the pipe frozen first so the house did not have to be drained.
Can a stopcock be replaced without turning off the water?
Yes. Where there is no working valve before it, the pipe is frozen on the supply side with a pipe freezing kit. A plug of ice forms inside and holds the mains back, the old stopcock comes off, the new one goes on, and the plug is left to thaw while the joints are watched.
The first photograph is the freezing. A blue jacket is wrapped round the pipe just before the old stopcock, and the spray can’s thin white tube runs into it.
The second is the old brass stopcock itself, on the grey pipe behind the tiles, with the jacket on the pipe before it.
A stopcock that will not turn
A stopcock is the valve where the mains water comes into a home, and it is there for the day something leaks. Often that is the first time in a long while anyone has tried to turn it. Old brass stopcocks seize. The spindle scales up, the washer inside goes hard, and the head either will not move or spins round without shutting anything off. When the stopcock is the only valve on that pipe, there is nothing before it to close, so the choices are to drain the system down or to find the water company’s valve outside and hope it still turns. Freezing the pipe is the third way. A jacket goes round the pipe on the supply side, the spray chills it, and the water inside turns into a plug of ice that holds the mains back. The old stopcock comes off, the new one goes on, and the plug is left to thaw by itself while the new joints are watched. The water in the rest of the house stays where it was, and nobody has to refill a tank or bleed a radiator afterwards.
A stopcock that turns but does not shut is the same job. The water keeps running past a worn washer, and the valve has to come off either way.
That is a stopcock replacement, or a stop tap replacement, done on a live pipe.
Behind the panel
This one sat behind a tiled panel in a bathroom, above the toilet cistern.
The panel came off, the pipe was frozen, and the work was done in the gap behind the tiles.
A panel like this is common where the pipes were boxed in and tiled over. It is the way in, and once the work is done it can go back on.
The job
A broken stopcock is worth changing before it is needed, because the day it is needed is the day it fails.
We wrote up a burst pipe under the floor and a toilet that keeps filling before, and our emergency plumber page covers the leaks that will not wait.
Ring 07546 185778 and say where the stopcock is and what it is doing, and send a photograph of it if you can.
