Types of Water Valves

Ball valves are commonly found in newer homes. They use a handle to control the placement of a hollow, perforated sphere in the mechanism. When the handle is turned, the hole immediately opens or closes the water flow.

You can tell by the handle placement whether the valve is opened or closed: when it is in the open position, the handle lies flat, in alignment with the flow, and when it is closed, the handle is perpendicular to the flow. They are often used for shut-off and control applications.

Butterfly valves are similar in design to ball valves. They have a rotating metal disc (nicknamed the “butterfly”) on a rod. A closed butterfly valve uses the disc to block water flow, while an open one rotates the disc a quarter turn to allow the water to flow. The valves belong to a family called “quarter-turn valves.”

Butterfly valves are lighter and less expensive than ball valves but are less durable and slower to operate. They tend to be used in industrial applications more than residential ones.

Check valves, also called non-return or one-way valves, are designed to allow flow in only one direction and to automatically prevent or “check” back flow if the fluid in the line reverses direction. These water supply valve types are small, simple and inexpensive, and are often used for backflow prevention in pumps, safety applications and such systems as lawn sprinklers. In addition, backflow preventers work in the same way but tend to be used for larger buildings such as apartment complexes or commercial properties.

Faucet valves are used specifically to control water flow in kitchen and bathroom faucets. They are different types of water valves designed for this purpose, including ball valves, cartridges, ceramic disc valves and compression valves. Many are used as tub and shower valves.

• Cartridge valves are designed with a movable stem inside a plastic cartridge that can be raised or lowered to regulate flow. Two-handle faucets often have separate cartridge valves for the hot and cold water.
• Ceramic disc valves use two discs stacked on top of one another in cartridge housings to regulate flow. Hardened ceramic resists wear and corrosion and is more durable than rubber washers that crack, harden and degrade over time. The ceramic discs move back and forth to create an airtight seal that prevents leaking.
• Compression valves are commonly found in older faucets and use a compression stem to press against the valve seat. They can be inexpensive but contain rubber or plastic washers that can crack or corrode, leading to leaks.

Gate valves, also called sluice valves, usually involves a round knob attached to a sillcock that, when turned, lowers or raises an internal gate or wedge to control the water flow rate. The familiar outdoor spigot for a garden hose offers an example of a gate valve.

These types of water valves allow customers to control the rate of the flow of water, like slow trickles as opposed to the full flow, but do not cause an immediate stop. They are more likely to be found in older houses and homes that have hose bibbs installed. They are often used with pipe diameters of 2 inches and up.

Globe valves are alternately called stop valves and contain a stem that controls a disc inside the mechanism. Although the valve body often has a bulging shape, many globe valves no longer feature a spherical design, despite the name “globe” remaining in common usage. They are easy to maintain, have effective throttling and shutoff abilities and are frequently used in outdoor residential faucets as well as boiler and cooling water systems.

Pressure relief valves, also called pressure reducing valves, are designed to reduce water pressure in plumbing systems, often to a specific limit. Homes that receive high-pressure water from a municipal source may need this type of pressure regulator to prevent damage to plumbing and appliances.

Supply stop valves, also called shut-off valves, are designed to stop the flow from a water supply. While most water valves can do this, stop valves provide easy shut-off mechanisms to allow people to find a leak near fixtures or when doing other plumbing work, without shutting off the water supply to the entire house.

Supply valves are commonly found attached to kitchen, bath and toilet fill valve supply lines. A shut-off valve is often a compression or quarter-turn valve and can be chosen in straight or angled designs depending on the flow path of the specific plumbing configuration. Ball valves are common types of supply stop valves.

Mixing valves are the reason water from a faucet comes out warm and not scalding hot. This valve ensures a safe water temperature for bathing and showering. The valve blends the hot water drawn from the water heater with cold water before it reaches the faucet. They are commonly made of brass, copper and bronze materials. Mixing valves are installed in homes and facilities where maintaining a safe water temperature is important.

These hot- and cold-water shut-off valves are connected by hoses to the appliance. A quarter turn of the washing machine valve handle stops the flow of water quickly if a hose bursts or leaks, minimizing the risk of flooding. Washing machine valves are commonly installed in an outlet box built into the drywall or panel to provide quick access to the water supply.