Water Shutoff Valves

Toilet and valve
Jupiterimages / Getty Images

A water shutoff valve is a small local valve used to control the flow of water to a plumbing fixture such as a faucet, tub, toilet or other plumbing fixture. These valves are usually found under the sink when controlling water flow to a faucet, and under the toilet tank when controlling water flow to a toilet tank. Shutoff valves for tubs are often found in a wall or tub access panel.

The shutoff valve consists of a handle that controls the valve's water flow; a water pipe inlet connection in the rear of the valve and a smaller water outlet connection on the top / side of the valve.

The water inlet connection is usually sized at 5/8" OD (1/2" ID copper pipe) and the water outlet connection is usually 3/8" OD. The water inlet connection can be a soldered or compression type connection. The outlet connection is often a compression connection.

The valve also comes in a straight and angle (90 degree) configuration.

Shut-off valves come in two valve types, compression valve type and ball valve type.

The ball valve type shutoff operates from the off to on position in 1/4 turn. It is the highest quality shutoff valve available and provides years of leak free operation. Definitely the way to go. The quarter turn shutoff ball valve is readily available online.

The multi-turn compression shutoff valve type operates from the off to on position with multiple turns and uses a compression washer to control the flow of water through the valve. Although cheaper than the quarter turn ball valve shutoff, the compression shutoff valve is prone to failure and leaks.

Also Known As: shutoff valve, multi turn supply stop, quarter turn supply stop