Compression faucets have been in use the longest and are the least expensive type. When the handle is turned, it raises or lowers a stem. At the base of the stem, a washer or seal opens or closes the water's passageway—a valve seat.
The problem with a compression faucet is that the rubber washer or seal wears out because, with most types, it grinds against the valve seat as it closes. When the washer wears, the faucet drips.
Some newer types raise and lower the washer without grinding it into the valve seat. American Standard's economy NuSeal faucets, for example, lift and lower the rubber washer vertically without rotating it.
The other three primary faucet types are called "washerless" because they use methods other than a washer and valve seat to control flow (O-rings and elastomeric seals to prevent leaking). Washerless faucets are a better value than compression faucets because they are more reliable.
The first washerless single-handle faucet was manufactured by Moen. The unique design has a hollow, plastic-and-brass cartridge insert that seals against the inside of the faucet body with O-rings. On single-handle models, water flow is controlled by an up-and-down movement of the cartridge; temperature is determined by rotation.
On the two-handle faucet, flow is controlled by a turn. Though faucets are available from a low of about $30 to high-end models in the $600 range, most of these are medium priced at from $60 to $175. These faucets are very reliable—leaks are generally due to simple O-ring failure. If cartridges ever require replacement, they cost from about $9 to $20, although new Eljer and Moen faucets carry a limited lifetime warranty against leaks and drips.
