How to Fix a Leaky Shower Valve: Cartridge Replacement and Stem Repair (2026)
A shower valve that drips from the shower head or runs cold water through the tub spout has a worn cartridge or stem. This guide covers identifying your valve type, shutting off the supply, and replacing the internal cartridge.
Shower valve dripping from the showerhead: the cartridge inside the valve body is worn. Shut off the water supply (at the access panel behind the shower or at the main), remove the handle and trim, extract the cartridge, and install a brand-specific replacement. Moen cartridges are the most common single-handle shower valve — the Moen 1225 or 1222 cartridge ($15–$25) is a direct replacement for most Moen single-handle showers.
Frequently Asked Questions
How do I identify my shower valve brand?
Look at the handle: Moen — single-piece handle, often oval-shaped, set screw behind or under a center cap. Delta — single-handle with a prominent handle design, often with a visible set screw at the top or side. Kohler — shows the Kohler logo on the trim plate or handle, often with a classic-looking round handle. For brand confirmation: remove the handle, look at the cartridge for any brand markings, or search by the trim plate design and dimensions. Many online resources let you identify a Moen or Delta cartridge by photo.
My shower drips only from the tub spout, not the showerhead. Is that different?
A drip from the tub spout when the shower is set to showerhead mode: the shower diverter is failing. The diverter is either built into the tub spout (a pull-knob type) or into the valve trim (a separate diverter handle). Tub spout diverter failure: unscrew the tub spout (counterclockwise from below with an Allen wrench) and replace the entire spout ($20–$40). Separate diverter valve failure: similar cartridge replacement as the main valve.
How do I shut off the water to a shower with no access panel?
If there is no dedicated access panel in the wall behind the shower: shut off the water at the main house supply. A common mistake is shutting off the right cold shutoff but not the hot supply from the water heater — both hot and cold must be off to work on a shower valve. After shutting off the main, open a faucet elsewhere to drain pressure from the lines.
I removed the cartridge but can't get the new one in. What am I doing wrong?
Most cartridges are directional — they only install in one orientation. The ears (tabs) on the cartridge align with slots in the valve body. Confirm the new cartridge matches the old one exactly (brand, model number). Some Moen cartridges have alignment tabs at 12 and 6 o'clock that must match the valve body slots. If the cartridge feels like it goes in two ways: there's a right and wrong way — usually marked with a hot side indicator. Never force a cartridge — if it's going in with resistance, it's mis-oriented.
After replacing the cartridge, the hot and cold are reversed. What happened?
The cartridge was installed rotated 180 degrees. Remove the cartridge, rotate it 180 degrees, reinstall. The cartridge determines which direction provides hot and which provides cold — there's no other adjustment. If a Moen cartridge: the small notch or tab at the top of the cartridge must point up. If replacing a Delta or other brand: photo the old cartridge orientation before removing.
Shower valve dripping from the showerhead: the cartridge inside the valve body is worn. Shut off the water supply (at the access panel behind the shower or at the main), remove the handle and trim, extract the cartridge, and install a brand-specific replacement.
Shower valve cartridge replacement is a DIY-friendly repair once you identify the brand.
What you need
- Replacement cartridge (brand and model-specific — take the old one to the hardware store)
- Allen wrench set (for set screws under handles)
- Flathead and Phillips screwdrivers
- Pliers
- Plumber’s grease
- Plumber’s cartridge puller (optional, for stuck Moen cartridges)
Step 1: Shut off the water
Find the access panel and shut off the shutoff valves (one hot, one cold). Or shut off the main supply. Open a faucet elsewhere to drain pressure.
Step 2: Remove the handle
Pry off the center cap on the handle. Remove the set screw with an Allen wrench. Pull the handle straight off.
Step 3: Remove the trim and cartridge retainer
Remove the trim plate (screws usually underneath or at corners). Expose the valve body.
Find the retaining clip on the cartridge — a U-shaped metal or plastic clip that holds the cartridge in place. Remove it with pliers.
Step 4: Pull the cartridge
Grip the cartridge stem with pliers and pull straight out. For stuck Moen cartridges: use a cartridge puller tool (available at hardware stores) to avoid damaging the stem.
Take the old cartridge to the hardware store to confirm the replacement part number.
Step 5: Install new cartridge
Lubricate the cartridge O-rings with plumber’s grease. Insert in the correct orientation (align tabs with slots). Push firmly until seated. Reinstall the retaining clip.
Step 6: Reassemble and test
Reinstall trim, handle, and cap. Restore water. Test hot and cold rotation. Check for leaks at the trim plate.
Related guides
- How to Fix a Leaky Shower — full shower leak diagnosis
- How to Replace a Shower Head — showerhead upgrade while supply is off
- How to Fix a Dripping Bathtub Faucet — related tub valve repairs
- Shut off the water supply
Look for an access panel in the wall behind the shower (in the adjacent closet or bathroom). The shutoff valves for the shower supply are often accessible from there. Turn both hot and cold valves off. If there is no access panel, shut off the main house water supply. Open a nearby faucet to drain residual pressure. Place a towel in the shower to catch drips.
- Remove the handle and trim
Find and remove the screw securing the handle — usually under a decorative cap at the center of the handle (pry off with a thin flathead). Some handles have a set screw on the side. Remove the handle by pulling or wiggling it off the cartridge stem. Remove the trim plate (the decorative escutcheon) — it usually pulls off or has 2 screws. Underneath the trim is the valve body with the cartridge.
- Extract the cartridge
The cartridge is held by a retaining clip or a threaded nut. For Moen cartridges: pull the retaining clip (a U-shaped clip at the top of the cartridge) straight up and out with needle-nose pliers. Then grab the cartridge stem with pliers and pull straight out — it may require firm, steady pressure. Note the orientation of the cartridge (especially which side faces hot vs. cold) before removing — photo it. For Delta ball valves: the assembly is different — remove the cap and collar, replace the ball, seats, and springs.
- Install the replacement cartridge
Match the replacement cartridge to the brand and model of the valve. Moen cartridges: the most common is the Moen 1225 or 1222 — confirm by the old cartridge number or faucet handle style. Insert the new cartridge in the same orientation as the old one — the hot/cold ears must align with the valve body slots. Press firmly until fully seated. Reinstall the retaining clip. Reverse the disassembly steps: trim plate, handle, screw, and cap.
- Test the repair
Turn on the water supply slowly. Test the shower: move the handle from cold to hot — temperature should transition smoothly. The valve should not drip from the showerhead when the handle is in the off position. If hot and cold are reversed: the cartridge was installed 180 degrees off. Remove and rotate it. If the valve still drips after cartridge replacement: the valve body seat may be scored, requiring valve body replacement.
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