How to Fix a Leaking Bathtub or Shower Faucet

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A tub or shower faucet that drips after you shut it off is almost always a worn part inside the valve, not the valve itself. On most modern single-handle showers, that part is a cartridge. On older two-handle setups, it is a pair of rubber seats and springs behind each handle. Replacing those wear parts is a job a careful homeowner can do, and it stops the drip without opening the wall. What this guide will not do is talk you into cutting into the wall or touching a soldered connection, because that is where a faucet repair turns into something only a licensed plumber should handle.

Two things make this post different from a generic “fix a leaky shower” walkthrough. First, it shows you how to pull a cartridge that mineral scale has locked in place, using the right tool instead of brute force that snaps the stem. Second, it draws a hard line: a worn cartridge or seat is yours to replace, but a leaking valve body, a cracked casting, or a drip at a soldered joint is not. To understand how the valve behind your wall actually mixes water, see our guide on how a shower valve works (post 036). To diagnose why a shower drips or won’t get hot before you commit to a repair, see our guide on shower valve problems (post 041).

Shut Off the Water: In-Wall Stops or the Main

Before anything else, kill the water and bleed the pressure. There is no shutoff under a tub or shower the way there is under a sink, so you have one of two options. Some newer valves include integral service stops, small screw-driven stops built into the valve body behind the trim plate that let you isolate just that fixture. If yours has them, close both the hot and cold stops with a screwdriver. If it does not, you have to shut off the water to the whole house at the main, which is covered in our guide on shutting off the water to your home (post 131).

Closing the valve is not the same as removing the pressure that is already in the lines. After you shut off the supply, open the tub or shower faucet and let it run until it stops, then open a faucet on a lower floor to drain the standing water down. Opening the valve while a line is still pressurized is how a small repair turns into a spray across the bathroom. Confirm the water is truly off and the line is depressurized before you take the handle off. That single check is what keeps this job safe to do yourself.

Removing the Handle, Escutcheon, and Retaining Clip

The handle almost always hides its own fastener. Most single-handle shower handles are held by a set screw tucked under a snap-on index cap or button on the front of the handle. Pry that cap off gently with a small flat screwdriver, back the screw out, and pull the handle straight off the stem. Two-handle faucets work the same way, with a screw under a hot or cold button cap on each handle.

Behind the handle sits the escutcheon, the round trim plate against the wall. It is usually held by a couple of screws or threaded onto the valve, sometimes sealed to the tile with a bead of caulk. Remove its screws or unthread it and ease it off. If caulk is holding it, score that bead with a utility knife first so you do not crack the tile.

What you find next depends on the brand, and this is the step where it pays to know your valve. Many Moen single-handle valves use a horizontal retainer clip that pins the cartridge into the valve body. That clip has to come out with needle-nose pliers before the cartridge will move, and it can drop, so cover the drain first. Delta and several others use a brass bonnet nut or a metal sleeve threaded over the cartridge instead. Work any nut gently. Manufacturer guidance warns that forcing a retaining nut can crack the valve body, which would turn a cartridge swap into a full valve replacement.

Pulling the Cartridge or Stem (and Freeing a Seized One)

Once the clip or nut is off, the cartridge should slide straight out. The trouble is that years of hard water leave mineral scale that locks it in the bore, and this is where most of these jobs go wrong. Do not pry against the valve body and do not yank the stem with pliers. Prying usually snaps the plastic stem off and leaves the cartridge body seized in place, which is far harder to remove than the whole part.

The fix is a cartridge puller made for your brand, which grips the cartridge and applies a steady straight pull along its axis, exactly the force that prying cannot deliver. Moen sells a puller, part 104421, that fits its common 1200, 1222, and 1225 single-handle cartridges, and the company’s own procedure is worth following. With the supply off and the retainer clip removed, you set the puller’s tabs between the tabs on the cartridge, thread the tool’s screw into the cartridge stem, then turn the tee handle to draw the cartridge straight up and out. For the 1200 and 1225 cartridges Moen has you pull the stem to the full-open position first; for the 1222 you rotate the stem so its notch faces up. If scale has it stuck hard, wrapping the exposed part in a rag dampened with white vinegar and giving it time to loosen the deposits helps before you pull again.

There is a point where patience and the right tool are not enough. If the cartridge will not come even with a proper puller, or the stem has already snapped off inside, the body is likely corroded past a homeowner repair. That is the moment to stop and call a licensed plumber who can free or replace the valve body without destroying it, rather than escalate the damage.

Replacing the Cartridge, Seats, and O-Rings by Valve Type

What you replace depends on what kind of valve you have, so match the part to the faucet before you buy. Cartridges are proprietary. A Moen cartridge will not fit a Delta body, and the part changes by model even within one brand, so guessing from a hardware-store wall is how people end up making two trips. Identify the faucet model first, then look up the cartridge that belongs to it through the maker’s parts diagram, or take the old cartridge in as your reference. Sourcing the right cartridge is the same problem as on a sink faucet, covered in our guide on replacing a faucet cartridge (post 025), which goes deeper on identifying the model and the lifetime warranty that may cover the part.

The replacement itself splits by valve type:

  • On a single-handle cartridge valve (most modern Moen, Kohler, and similar), you pull the whole cartridge and drop in a fresh one as a unit. Coat the new cartridge body with a thin film of plumber’s silicone grease, not petroleum grease, so it seats smoothly and the O-rings last.
  • On a two-handle Delta and similar valves, the drip usually comes from worn rubber seats and the metal springs beneath them, not the whole cartridge. You lift out the old seats and springs and press in new ones, spring first, then the seat. Delta’s instructions have you grease the new parts and confirm they sit flat.
  • On any valve, inspect the O-rings on the stem or cartridge while it is apart. A hardened or flattened O-ring is a cheap part that causes a slow weep, and it is worth replacing while you are in there.

One detail matters more than it looks: orientation. Cartridges and stems are keyed with a notch, flat, or tab that has to line up with a matching feature in the valve body. Seat one a half turn off and it will physically fit but run backward, so hot comes out when you ask for cold. Note how the old part was keyed before you pull it, and match the new one to it.

Reassembling and Re-Sealing the Escutcheon

Put it back together in the reverse order, gently. Reinstall the retainer clip fully into its slot or thread the bonnet nut down snug rather than cranked, since over-tightening here is the same risk that can crack the body. Slide the handle back on, set the screw, and snap the index cap into place.

If your valve is a modern anti-scald model, there is one step generic guides skip, and it matters. Pressure-balancing and thermostatic valves carry a maximum-temperature limit stop, a setting that caps how hot the water can get, and pulling the cartridge can reset or disturb it. Kohler, for example, has you set the limit stop on its Rite-Temp valves so the output never exceeds 120 degrees Fahrenheit. After a cartridge swap, run the water to the hottest the handle allows and check it with a thermometer. The U.S. Consumer Product Safety Commission notes that water at 150 degrees can cause a third-degree burn in about two seconds, and at 140 degrees in about six seconds, which is why that limit stop exists. Set it back so the maximum is no hotter than 120 degrees before anyone uses the shower.

Re-seal the escutcheon last. Reattach it, then run a fresh bead of waterproof caulk along its top and sides where it meets the tile, leaving the bottom edge unsealed so any water that gets behind it can drain out and show you there is a problem. The caulking technique itself is covered in our guide on caulking around tubs and showers (post 197). Turn the water back on slowly, watch the valve area as pressure returns, then run the faucet hot to cold and feel for smooth motion with no drip.

When the Drip or Leak Means the Valve Body Itself Has Failed

A new cartridge or fresh seats fix a worn-out valve. They do not fix a valve body that has cracked, corroded through, or developed a leak at a soldered joint, and telling those apart keeps you from chasing the wrong repair. If the faucet still drips after a correct cartridge swap, and the cartridge is genuinely the right part seated the right way, the problem has moved past the wear parts. A pitted or scored valve seat that a cartridge cannot seal against, a hairline crack in the casting, or water appearing behind the wall rather than at the spout all point at the body.

That is a stop-line, not a next step. The valve body on a tub or shower is usually soldered or brazed to the copper supply lines inside the wall, and reaching it means opening the wall and often sweating new copper joints with a torch. That work needs the wall open, specialized tools, and a repair that meets local plumbing code, and a bad joint hidden in a wall can do slow, expensive water damage you will not see for months. There are no step-by-step instructions here for cutting into pressurized in-wall pipe, by design. If the leak is at the body or a soldered connection, the right move is a licensed plumber, not a deeper DIY attempt. If you are still trying to pin down whether the water is even coming from the faucet versus the pan, grout, or a supply line behind the wall, our guide on what causes a leaking shower (post 043) walks through isolating the real source first.

This is general information, not professional plumbing advice. If a cartridge will not free with the proper tool, the valve body is cracked or corroded, the leak is at a soldered connection, or water appears behind the wall, have a licensed plumber evaluate it.

Sources

  • Moen, Using a 104421 Cartridge Removal Tool: https://solutions.moen.com/ArticleLibrary/Usinga104421CartridgeRemovalTool
  • Moen, Cartridge Puller for 1200, 1222 and 1225 Single-Handle Cartridges (104421): https://www.moen.com/products/Moen/Moen-Cartridge-Puller-for-1200-1222-and-1225-Single-Handle-Cartridges/104421
  • Delta Faucet, RP48025 1300/1400 and 13/14 Cartridge Installation Instructions: https://media.deltafaucet.com/MandI/48027RevB.pdf
  • Delta Faucet, Cartridge Assembly 1300/1400 Series (RP19804) Parts: https://www.deltafaucet.com/parts/product/RP19804.html
  • Kohler Assist, Adjust the Temperature on a Rite-Temp Shower Valve: https://assist.kohler.com/en/valves-shower-bath/Adjust-the-Temperature-on-a-Rite-Temp-Shower-Valve
  • U.S. Consumer Product Safety Commission, Tap Water Scalds (Publication 5098): https://www.cpsc.gov/s3fs-public/5098.pdf

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