What Are the Different Types of Water Valves?

Water valves allow the flow of water to be shut off at one or more points throughout the plumbing system. While some valves only control the flow of water, other valves also control the temperature of that water. The most common problem with water valves is water leaks. Leaks typically occur when the washers and seals within the valves' assembly crack or distort. Before a repair can be performed, it is imperative to first identify the types of valves.

Compression Valves

Compression valves are most commonly used in two-handle faucet designs. One valve is used to control the flow of cold water, whereas the other valve controls the flow of hot water. When turned, each valve handle compresses against rubber washers, which in turn regulates the flow of water which passes through the valve. Compression valves use stems of varying designs, but all designs utilize neoprene washers. When compression valves leak, the problem most likely lies with a worn O-ring.

Cartridge Valves

Cartridge valves are sometimes referred to as "washerless" valves. Cartridge valves, unlike compression valves, are most commonly controlled by a single handle, although some cartridge models utilize two handles. Cartridge valves can easily be identified, as they use a single cylindrical plastic or metal cartridge which rests within the faucet body. When the valves' handle is lifted, the valves' stem raises. The valves' holes then align with holes within the cartridge. If the handle is twisted, cold and hot water are allowed to mix, thereby regulating the temperature of the water. Leaks around the base of the cartridge are usually caused by corroded O-rings, and drips from the valves' spout can usually be traced to a worn cartridge seal.

Disk Valves

Like cartridge valves, disk valves are also known as "washerless" valves. Disk valves are generally only used to control single-handle kitchen sink faucets. Disk valves can be easily identified by their wide cylinder located within the faucet's body. The disk faucet utilizes ceramic disks which fit very tightly against each other. Each disk has a series of holes. The inlet hoses allow cold and hot water to enter the valves, and the outlet hole allows the water to pass through the valves' spout. When the handle is lifted, the upper disk slides against the lower disk, which allows the water to mix. Disk valves are among the most durable valves and rarely need attention. Leaks can generally be traced back to the cylinder or the three neoprene seals located below the cylinder.

Ball Valves

Ball valves are also referred to as "washerless" valves. Ball valves utilize a single valve to control the flow of hot and cold water, and are most commonly used in the kitchen, although ball valves are sometimes used in a single-handle shower or bathtub design. Ball valves are easily recognizable by the hollow metal or plastic ball. As the ball rotates with the handle, the temperature and flow of water can be regulated. Most ball valves have a cylindrical metal cap just below the handle. If leaks come from the valves' spout, tightening the cap commonly stops the leaks. If the leak persists, the problem is likely from a corroded valve seat, a bent spring or the ball itself.

Repairing Valves

Leaking water valved is the most common plumbing problem within the home. Over time, persistent water leaks can result in an increased water bill and can even cut a channel into the surface of a sink or bathtub. Thankfully, repairing water valved is a relatively easy task which can be performed quickly. Repair kits are readily available from most hardware stores and usually come with instructions. It is important to identify not only which type of faucet requires repair, but also which manufacturer produced the particular valve. When in doubt, bring the defective valve to the store.