7 Types of Water Shutoff Valves
A plumbing system needs a main shutoff valve as well as valves for branch lines and fixtures. Here's a rundown of the various types.
Shutoff valves are required equipment on home plumbing systems. The plumbing code requires a main shutoff for the entire system, and individual fixtures like sinks, toilets, outdoor faucets and washing machines should each have their own. These prevent a flood if a leak occurs, and makes general repairs easier.
Shutoff valves must be easy to find and access. Case in point: My friend needed a new toilet, and because his toilet shutoff valve was old and rusted, it had to be replaced as well. However, the bathroom lacked a dedicated shutoff valve.
After a long, unsuccessful search for the main shutoff valve in the house, we purchased a special tool that allowed us to turn off the water at the street. We finally found the main shutoff by accident. It was outside, under a shrub and partially buried in the ground!
Besides stopping the water altogether, some adjustable valves reduce pressure on a network by regulating the flow to it. They’re especially handy outdoors, letting you regulate the distance water travels to the sprinklers.
Several shutoff valve types are available, and some work better than others for particular situations.
Standard Ball Valve
A standard (full-port) ball valve consists of a ball with a single hole installed in a tight-fitting chamber. Using the handle on top of the valve, you can rotate the ball through 90 degrees. When the hole aligns with the pipe, water flows freely. When it’s perpendicular to the pipe, the flow stops. It’s a non-adjustable, all-or-nothing valve.
Ball vales are most commonly used as the main water shutoff valve in a house, but they have multiple other uses as well. They come in a range of sizes with diameters, from huge to the tiny quarter-inch valves used for drip irrigation systems. The 64-inch CIRCOR valve, controlling water flow from the Ras Azawr desalination plant to Riyadh in Saudi Arabia, is the world’s largest.
Ball valves can be made of brass, PVC or ABS plastic and stainless steel, among other materials.
Non-Standard Ball Valve
There are many variations of the standard ball valve.
- Reduced-port ball valves: These have a slightly smaller aperture (hole), increasing the pressure in the outlet side when fully open — much like increasing the pressure from a hose by putting your thumb over the outlet.
- Multi-port ball valves: These have more than one ball connected to a single handle. Each ball controls the flow through separate inlets and outlets. You can use this type to control water through more than one set of pipes at the same time.
- V-port ball valves: These feature a ball with a V-shaped passage instead of a simple hole, allowing the user to control water flow rather than just turn it on and off. This type often comes with a spoked wheel handle to make incremental adjustments of flow more accurate.
Gate valves are usually found near the water heater, where one with a blue handle controls the cold water inlet and one with a red handle controls the hot water outlet.
When you turn the spoked wheel handle, it actuates a screw drive that moves a flat metal partition (gate), inside the valve, up and down. With the gate fully closed, the water is shut off. But you can adjust the flow to a limited extent by leaving the gate partially open.
Like ball valves, gate valves are bidirectional, meaning water can flow through them in either direction. They can be made of brass or PVC with screw thread, glue or sweat connections. They’re used as frequently as ball valves for main water shutoffs.
Instead of lifting and lowering a gate, the handle operates a plunger that presses against a valve seat when the valve is closed. There’s also a baffle that separates the inlet path from the outlet, reducing water pressure on the outlet side. The mechanism allows for more accurate pressure control.
Unlike a gate valve, a globe valve is unidirectional. It has clearly marked inlet and outlet ports and must be installed so that water passes through it in the right direction.
Angled Fixture Valve
Also known as a stop valve or angle stop, this is the common under-sink valve that’s also used for toilets. Most are made of chrome, brass or plastic. As the name suggests, the inlet and outlet ports are usually at right angles to each other.
The ports are also usually different sizes. The inlet port is usually 1/2- or 3/4-in. in diameter, while the outlet can be 1/4- to 1/2-in.-dia. Angle stops may have sweat or threaded connections, but most have compression fittings. These allow you to connect them to straight lengths of pipe without glue or solder.
Some angle stops incorporate gate or globe valves. Most contemporary ones contain ball valves, and you rotate the handle through 90 degrees to shut off the water.
Electric Diaphragm Valve
The type of valve that controls sprinkler systems and hydronic heating systems features a solenoid controlled by an external control panel. Valves for hydronic systems are usually brass, while sprinkler valves are most often plastic. The inlet and outlet ports may be parallel or angled with respect to each other, and they’re usually the same size.
This type of valve functions like a globe valve. It has three components: The valve body, consisting of the inlet and outlet ports separated by a baffle; a solenoid that raises and lowers a plunger to stop water flow; and a bonnet that contains a rubber diaphragm. The diaphragm regulates pressure inside the valve by raising and lowering it via a screw control on the top of the bonnet.
Also known as a saddle valve, this small shutoff is intended for use with copper tubing feeding refrigerator ice cube makers and furnace dehumidifiers. The valve attaches to a pipe clamp you tighten around the supply pipe. As you do this, a needle pierces the pipe and feeds water to a one-quarter-inch outlet port.
Needle valves are super easy to use. Although you may find one at the building supply store, installing it won’t meet code in most places. That is because any small impact can make the valve leak.
If you find an existing needle valve on your refrigerator water line, it’s best to replace it with a different kind of valve. Failing that, try not to disturb it and it probably won’t leak.