There are a few different types and combinations of faucets: single-handle or two-handled shut-offs that are compression or washerless (cartridge, ball or disc mechanism).

A compression faucet stops water by tightening down a rubber washer to block water flow. A washerless faucet uses a rotating mechanism -- like a ball or valve -- to open and shut water flow.

A compression faucet usually has threaded brass stems that open/close firmly. A cartridge faucet has brass or plastic valves with holes in them and operate more easily.

Tips Before You Start

• Close the sink drain to avoid losing any parts.
• After locating the leak, shut off both water supplies before removing any parts.
• Tape wrench jaws to avoid marring the faucet's finish.
• Write down and/or lay out parts to remember their order.
• Buy a repair kit that includes a special adjusting ring wrench, seals, springs and O-rings rather than one or two pieces. Washer assortment kits may also be better than more expensive single washer packaging.
• If the faucet still leaks after installing a kit, the outer housing is probably cracked and buying a new faucet is probably the only way to fix the leak.

Repairing Double-Handled Faucets

If a faucet is leaking, a washer (for compression) or O-ring (for cartridge) probably needs to be replaced.

Pry off the handle's decorative cap to access the knob screw. Unscrew and remove the knob to expose the stem. Make sure the water is turned off.

For a compression handle, loosen the "packing" nut holding the stem. Remove the stem, flip it over and check the condition of the washer and O-ring. Replace the washer and O-ring if they show any wear or fraying.

A cartridge handle is repaired about the same way. Lift out the cartridge, check the O-rings and replace them as needed. As a last resort, replace the cartridge if the leak persists.

Re-install the assembly, turn on the water and check for drips. If a compression faucet still leaks, the seat where the valve seals may need to be cleaned, or re-cut with a seat cutter tool.

To stop a leak around the handle, add a packing washer over the stem. If an old compression type handle still leaks, remove the packing nut and wind packing (a string gauze) around the nut to seal the assembly.

Fixing Ball-Type Faucets

A ball faucet can leak in several places: around the handle, spout, collar, base. Therefore, we'll describe how to repair the whole works. Yet, fixing your faucet may only involve one of these steps.

Locating the leak and shut off the water. Remove the set screw holding the handle. Using the kit's wrench, snug down the adjusting ring if it's loose and slowly turn the water back on to see if the leak has stopped.

If the ring is already tight or the leak persists, turn off the water and remove the adjusting ring.

Take off the plastic or ceramic cam piece and its seal that sets on the ball valve. Replace the seal if needed. Make a note of how the ball valve slot lines up with its small alignment pin then remove the ball.

Most models have two rubber seals and springs that set under the ball. Remove them, clean out any deposits and replace with new seals and springs.

On the outside of the housing, cut off the rubber O-rings and roll on new ones and re-install the faucet.

Repairing A Single-Handle Cartridge Faucet

After locating the leak and shutting off the water, pry off the faucet's top cap, remove the screw and lift off the handle piece.

Remove the lock nut and retaining clip holding the cartridge in place. Lift out the cartridge and inspect its seals. In most cases, the cartridge piece doesn't need replacing, but any worn or frayed seals should be replaced.
While the cartridge is out, inspect and replace the O-rings on the outside of the housing. Just cut them off and roll on new ones.

Re-insert the cartridge, align it as removed, and pop on the retaining clip. Fit the faucet back on and tighten down the lock nut. Re-position the handle, screw it down and put the cap back on.