normally on the water pipe feeding into the toilet from below but not all plumbers put these on even though its the regs so if u cant see it most likely its not there
kash
September 2010
If you have one fitted, it should be close to the cistern. If you cant see it, you haven't got one. It's a good idea to fit isolation valves to all of your tap supplys, washing machines etc, saves turning the water supply off. Get them cheap from Screwfix.
Homer
September 2010
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