How to Replace a Shower Cartridge
Updated February 20, 2026
Swap a worn shower valve cartridge to fix temperature problems, drips, and hard-to-turn handles. The part inside the wall that controls everything.
Overview
The shower cartridge is the internal mechanism inside the valve body that controls water flow and temperature mixing. When it wears out: dripping when off, temperature swings, difficulty turning the handle, or the handle will not shut off fully. Replacing the cartridge fixes all of these without replacing the entire valve or opening the wall. The cartridge slides in and out of the valve body once you remove the handle and trim. Brand-specific -- you need the exact cartridge for your valve. Moen 1222, Delta RP19804, Kohler GP77759 are among the most common.
What You'll Need
Safety First
- Turn off the water supply to the shower before removing the cartridge. Use the shut-off valves for the shower if accessible, or shut off the main.
- Some cartridges are under spring tension. When pulling the cartridge, grip firmly -- it can release suddenly.
Step-by-Step Instructions
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Identify Your Valve Brand and Cartridge
Before touching anything, identify the valve brand. Look for a logo on the trim plate or handle (Moen, Delta, Kohler, Pfister, etc.). If no logo, check the builder's spec sheet or search the trim style online. Once you know the brand, you can find the correct replacement cartridge. Buy it before starting -- you do not want the shower torn apart while you go to the store.
Tip: Moen: single-handle with a cylindrical cartridge (1222 or 1225 are most common). Delta: single-handle with a ball or cartridge (RP19804 series). Kohler: cartridge varies widely by model. Take a photo of the valve and trim, bring it to the store if unsure. -
Turn Off Water and Remove the Handle
Shut off the water supply. Open the shower valve to drain remaining water. Pop off the decorative cap on the handle (pry with a flathead screwdriver). Remove the handle screw (Phillips or Allen, depending on brand). Pull the handle off. If it is stuck, use a handle puller ($10) -- do not pry with a screwdriver or you will crack the wall tile.
Tip: Moen handles use a small Allen screw under the cap. Delta uses a Phillips screw. Kohler varies. Having the right screwdriver or Allen key before you start saves frustration. -
Remove the Trim Plate and Retaining Clip
Unscrew or unclip the escutcheon (trim plate) from the wall. You will see the valve body recessed in the wall. Look for a retaining clip -- a small U-shaped metal clip that holds the cartridge in place. Pull it out with needle-nose pliers. Note its orientation so you can reinstall it the same way.
Tip: Take a photo before removing the clip. Some valves have the clip in a horizontal slot, others vertical. Incorrect reinstallation can prevent the cartridge from seating properly. -
Pull the Old Cartridge
Grip the cartridge stem with pliers and pull straight out. Some cartridges slide out easily. Others are stuck from mineral buildup and corrosion -- this is the hardest part of the job. Moen includes a cartridge puller tool with their replacement cartridges (or buy one separately for $15). For stuck cartridges: twist back and forth while pulling. Apply penetrating oil around the cartridge body and wait 10 minutes if it will not budge.
Tip: Moen 1222 cartridges are notorious for sticking. The Moen cartridge puller tool is not optional -- it is nearly impossible to pull a stuck 1222 by hand. Worth every penny. -
Install the New Cartridge
Apply a thin coat of silicone plumber's grease to the O-rings on the new cartridge. Align the cartridge with the valve body -- there are orientation tabs or flats that only fit one way. Push straight in until it seats fully. You should feel it click or bottom out. Reinstall the retaining clip in the same orientation as the original.
Tip: If the cartridge will not slide in, check orientation. Most have a flat side or notch that must align with the valve body. Forcing it in the wrong orientation damages the O-rings and causes leaks. -
Reassemble and Test
Reattach the trim plate. Reinstall the handle and tighten the screw. Replace the decorative cap. Turn the water supply back on slowly. Test the shower: check for drips with the valve off, test hot and cold, test temperature adjustment through the full range. Check behind the trim plate for leaks at the valve body.
Tip: If hot and cold are reversed after installation, the cartridge is in 180 degrees wrong. Shut off water, pull the cartridge, rotate it 180 degrees, and reinstall. Common with Moen and Delta.
Pro Tips
- Moen offers a lifetime warranty on their cartridges. If you have a Moen valve, contact them before buying a replacement -- they will often send a free cartridge.
- Keep the old cartridge. If the new one does not fix the problem, you can reinstall it while troubleshooting further.
- While the cartridge is out, inspect the valve body bore for pitting, scoring, or heavy mineral buildup. Light buildup: clean with vinegar and a brush. Heavy scoring: the valve body may need replacement (a bigger job).
- If you do not know your valve brand and cannot identify the cartridge, pull the old one first and take it to a plumbing supply house. They can match it visually.
- Apply plumber's grease to the O-rings every time. Dry O-rings tear during installation and cause leaks immediately.
When to Call a Pro
Call a plumber if the cartridge is stuck and you cannot extract it even with a puller tool (forcing it can break the valve body), if the valve body is scored or damaged and needs replacement (requires opening the wall), if the valve is an older model and the replacement cartridge is discontinued, or if you are unsure which cartridge you need and do not want to risk buying the wrong one.