Quick Answer:
If your showerhead drips after a cartridge replacement, start by confirming the new cartridge is the exact part your valve requires, then check and reseat the cartridge and O-rings. Lubricate O-rings only with the manufacturer-recommended grease. If the valve body is scratched or scored, the valve may not seal and replacement can be required.
Why This Happens
- A cartridge that isn’t the correct part can leave gaps or fail to align seals, causing a drip.
- Old or improperly seated O-rings won’t form a proper seal even if the cartridge is correct.
- Valve bodies can be damaged during removal or by debris; scratches, grooves, or scoring let water bypass the cartridge.
- Temperature or pressure changes can make a marginal seal show as a drip only in certain conditions — see Dripping only after long showers and Shower drips when water heater runs for related causes.
Step-by-Step What to Do
1. Turn off the water and relieve pressure
Shut off the water to the shower at the isolation valves or main shutoff. Open the shower briefly to drain any remaining pressure.
2. Confirm the cartridge part number matches the valve
Check the replacement cartridge’s part number against the valve model printed on the valve body or in the valve documentation. Manufacturers often make similar-looking cartridges that are not interchangeable. If you can’t find markings, take the old cartridge to a parts supplier or consult the valve manufacturer.
3. Remove and inspect the cartridge and valve body
- Carefully remove the cartridge according to the manufacturer’s instructions.
- Inspect O-rings, seals, and the cartridge skirt for nicks or wear.
- Inspect the valve body bore for scoring, deep scratches, or corrosion — these will prevent a fluid-tight seal.
4. Reseat and lubricate O-rings per manufacturer instructions
Replace any damaged O-rings. Lightly coat O-rings with the lubricant specified by the valve manufacturer (usually a silicone-based plumber’s grease). Do not use petroleum-based greases unless the manufacturer allows it. Carefully slide the cartridge back into position, aligning any tabs or orientation marks, and secure it as directed.
5. Test for leaks slowly
Turn the water back on slowly and test both hot and cold. Let water run for a minute, then shut it off and watch for drips. Repeat the test after a short shower run to confirm the seal under normal conditions.
6. Consider the valve body condition
If you see visible scoring or the valve bore is distorted, the cartridge may never seal properly. In that case, the valve body often needs repair or replacement — this is commonly a job for a professional unless you have the right parts and experience.
What Not to Do
- Don’t force a mismatched cartridge to fit. Forcing it can break plastic parts or make the valve body worse.
- Don’t assume any silicone or grease is acceptable — use the lubricant the manufacturer specifies.
- Don’t ignore a scored or damaged valve body; compatibility and a clean bore matter. If the valve body is damaged, hiring a plumber is appropriate.
When to Call a Professional
- If the cartridge part number is unclear and you can’t verify compatibility.
- If the valve body is scored, corroded, or otherwise damaged.
- If you’re uncomfortable disassembling the valve or the drip continues after reseating and O-ring replacement.
Safety Notes
- Turn off water and relieve pressure before working on the valve to avoid scalding or flooding.
- Follow the valve manufacturer’s instructions exactly for removal, installation, and lubrication.
- Use proper tools and avoid excessive force—plastic parts can crack and create more costly problems.
Common Homeowner Questions
- Q: How do I know the cartridge is the right one?
A: Match the part number to the valve model or compare the old and new cartridges visually and by dimensions; consult the manufacturer if unsure. - Q: Will new O-rings fix any drip?
A: They will fix many leaks, but not leaks caused by a damaged valve bore or the wrong cartridge. - Q: Can I replace the valve body myself?
A: Possible for a confident DIYer, but valve body replacement can require cutting into the wall and soldering or special fittings—hire a plumber if you’re not experienced.
For more related articles, see the Dripping Showerhead After Shutoff hub.