Replace the worn faucet seal or cartridge
Turn off the water, identify the faucet type, and replace the worn washer, cartridge, or valve stem that is letting water pass. The right part depends on the faucet design, so take the old component with you when buying a replacement.
- First step Shut off water supply
- Likely cause Worn washer or cartridge
- Key tool Exact replacement part
A dripping bathtub faucet often wastes water and can leave mineral marks, but many leaks can be fixed by replacing a worn internal seal. This guide covers common compression, cartridge, and other washerless faucets. Before starting, identify the faucet style and locate its shutoff valves; if there are no accessible individual valves, you may need to shut off the home’s main water supply. If you cannot confidently identify the parts or the plumbing is corroded, call a plumber rather than forcing anything.
What You’ll Need
- Replacement washer, cartridge, or valve stem that matches your faucet
- Adjustable wrench and the correct screwdriver or hex key
- Slip-joint pliers, if needed, and a cloth to protect the finish
- Small container or towel to catch remaining water
- Phone or camera to record the assembly before disassembly
- Optional: silicone plumber’s grease approved for faucet parts
Some faucets require a cartridge-pulling tool or a special handle-removal tool. Check the faucet’s brand and model, often printed on the trim or listed in the original paperwork, before purchasing parts. Do not assume a similar-looking cartridge will fit.
Step-by-Step
- Confirm the source. Dry the spout and handles, then watch where water appears. A steady drip from the spout when the handles are fully off usually points to an internal valve seal. Water leaking around a handle may indicate a stem seal or cartridge problem. If water emerges from behind the wall or around the tub spout’s connection, the repair may involve plumbing beyond the faucet trim.
- Shut off the water. Close the hot and cold shutoff valves serving the tub, if present, by turning them clockwise. If there are no local valves, shut off the home’s main supply. Open the faucet to relieve pressure and confirm the water stops. If it continues flowing, locate the correct shutoff before taking anything apart. Cover the drain so small screws cannot fall into it.
- Protect and document the faucet. Put a cloth over the tub surface and use another cloth between tools and finished metal. Take a photo of the handles, trim, and any parts as you remove them. Work gently: plated finishes scratch easily, and old plastic components can crack.
- Remove the handle and trim. Look for a cap hiding a handle screw, a visible screw, or a small set screw at the side or underside of the handle. Lift or pry off a cap carefully with a plastic tool, then remove the screw with the matching driver or hex key. Pull the handle straight off. Remove the decorative escutcheon or sleeve as the design allows; avoid twisting trim against tile or applying force to a stuck fitting.
- Identify the valve type. A compression faucet often has separate hot and cold handles that turn several times and uses a washer at the end of a valve stem. A cartridge faucet commonly moves through a partial turn or a single handle and contains a removable cartridge. Other washerless designs may use ceramic discs or a pressure-balancing valve. If the layout does not match, check the manufacturer’s instructions instead of guessing.
- Remove the faulty part. For a compression faucet, use a wrench to loosen the stem-retaining nut, then unscrew and withdraw the stem. Inspect the rubber washer at its tip and the small screw holding it. For a cartridge faucet, remove its retaining clip or nut as specified by the maker, note the cartridge’s orientation, and pull it straight out. Use a cartridge tool if required. Do not pry against the valve body or pull hard enough to damage pipes behind the wall.
- Match and replace the seal or cartridge. Take the old part to a plumbing supplier or compare it with the faucet maker’s parts diagram. Replace a worn compression washer with the exact size and shape; replace a damaged retaining screw if needed. For a cartridge, use the exact compatible model and align its tabs and hot-cold orientation as directed. Apply only a thin film of faucet-safe silicone grease to seals if the manufacturer allows it. Do not use petroleum jelly or pack thread tape around a cartridge.
- Inspect accessible surfaces. Check the valve seat or cartridge opening for grit, mineral deposits, or obvious damage. Wipe away loose debris with a soft cloth. A deeply scored, cracked, or corroded seat may continue to leak even with a new washer; seat replacement or valve repair may require a special tool or professional service. Do not scrape the surface with a knife or abrasive material.
- Reassemble in order. Put the stem or cartridge back in its original orientation and reinstall its clip or retaining nut. Tighten nuts snugly, not excessively; overtightening can crack parts or damage threads. Refit the trim and handle, then secure the screw and cap. Ensure the handle moves freely without rubbing the trim.
- Restore water and test. Close the faucet, reopen the shutoff valves slowly, and check around the handles and trim for leaks. Turn on hot and cold water separately, then shut the faucet off and watch the spout for several minutes. If it still drips, shut off the water again and recheck part compatibility, orientation, and installation. Do not leave a persistent leak unattended.
Common Mistakes
- Replacing the wrong part: A washer will not fix every faucet. Identify the valve design and match the exact cartridge or stem.
- Skipping the shutoff: Opening a pressurized valve can cause flooding. Confirm the water is off before disassembly.
- Forcing stuck trim: Corrosion and mineral deposits can bind parts. Use the correct tool and gentle pressure; stop if the valve body or wall begins to move.
- Overtightening: Excess force can damage threads, seals, handles, or plastic clips. Tighten fasteners firmly but carefully.
- Using the wrong lubricant or sealant: Petroleum products may damage rubber, and tape is not a fix for a cartridge leak. Follow the faucet maker’s directions.
- Ignoring a damaged valve seat: A new washer may fail quickly if the surface it presses against is rough or pitted.
Tips
- Keep the hot and cold parts separate as you remove them so they return to the correct sides.
- Photograph each layer of trim and hardware; older faucets may not match diagrams for newer models.
- Use a basin wrench or the specified cartridge tool only when needed, and keep tools from bearing against finished surfaces.
- If you cannot find the tub’s shutoff valves, know where the home’s main shutoff is before beginning.
- Replace a washer or cartridge with a quality, exact-fit part rather than stretching or trimming a near-match.
Troubleshooting
The faucet still drips after replacement: The part may be incorrect, reversed, or not fully seated. Shut off the water, remove it, check its orientation and seals, and inspect the valve seat. A worn seat or damaged valve body may need repair.
Water leaks around the handle: The stem packing, O-ring, or cartridge seal may be worn, or a retaining nut may be loose. Check the faucet’s parts diagram and replace the appropriate seal; avoid tightening the nut excessively.
The handle is stiff or will not turn: A cartridge may be misaligned, mineral deposits may be present, or a part may be damaged. Do not force the handle. Shut off the water and verify fit and orientation; replace a damaged cartridge.
The shutoff valve will not close: Do not proceed with the faucet open to the supply. If the main shutoff also fails or a valve begins leaking, stop and contact a plumber.
The leak comes from behind the wall: This is not a handle-seal repair. Shut off the water if you can do so safely and arrange a plumbing inspection, since concealed leaks can damage the wall and surrounding structure.
Frequently Asked Questions
Why does my bathtub faucet drip when it is turned off?
A worn washer, cartridge, O-ring, or damaged valve seat may let water pass through the closed valve. The faucet design determines which part is responsible.
Do I need to replace both hot and cold cartridges?
Not necessarily. Replace the faulty component with the correct part. If both sides are the same age and show wear, inspect both and follow the manufacturer’s recommendation.
Can I fix a leaky faucet without turning off the water?
No. Shut off the hot and cold supply, or the home’s main water supply if local valves are unavailable, before removing the handle or valve parts.
How do I know which replacement cartridge to buy?
Find the faucet’s brand and model or take the removed cartridge to a plumbing supplier. Match its shape, length, tabs, and part number; similar-looking cartridges may not fit.
When should I call a plumber?
Call a plumber if you cannot shut off the water, the valve is badly corroded, the faucet leaks behind the wall, or the correct repair requires tools or access you do not have.
Further reading: U.S. Department of Energy