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How to Clean a Clogged Shower Cartridge

Ask This Old House plumbing and heating expert Richard Trethewey travels to New York City to teach a homeowner how to clean her shower cartridge when it gets clogged.

Steps for cleaning a clogged shower cartridge:

1. Start by covering up the shower drain with a drop cloth to prevent any pieces from falling down the drain.

2. Remove the handles, escutcheons, and cover plate for the shower valve.
a. This will vary, depending on the manufacturer. In general, look for small circles that could be concealing screws that are holding the handles in place. These can usually be removed with an Allen wrench.
b. Be careful to loosen only the handles and not actually turn them; otherwise, the water will turn on.

3. Shut the hot and cold water lines off. Sometimes, these will be in the wall next to the valve and can be closed with a screwdriver and with a shutoff. If not, the water may need to be shut off at the main line.

4. Loosen the nut holding the shower cartridge in place with an open end adjustable wrench.

5. Carefully pull the shower cartridge straight out of the valve. Do this carefully to prevent any damage to either the cartridge or the valve.

6. Scrub the cartridge until all impurities are off of it. This can be done with any soft bristled brush, including a toothbrush, and a little bit of water.

7. In a bowl, mix a little bit of water and white vinegar. Soak the cartridge in the mixture for a couple of hours.

8. Place the cartridge back in the valve and tighten it in place with the nut.

9. Turn the hot and cold water back on.

10. Add the cover plate, escutcheons, and shower handles based on the manufacturer’s design.


Every plumbing manufacturer has a slightly different shower valve, so it’s important to match the manufacturer when buying replacement cartridges. Depending on the shower valve, replacement cartridges can be found online, in plumbing supply houses, or for more common valves, in home centers. The shower valve the homeowner had in this piece was a DaVinci Thermostatic Mixer, which she sourced from AF Supply in Manhattan.

In some cases, the cartridge might just need to be cleaned, which can be done with a little bit of vinegar and a toothbrush, which can be found at any grocery store.

A 4-in-1 screwdriver and a pair of slip joint pliers are needed to remove the trim and access the cartridge. These can also be found at home centers.

Expert assistance with this segment was provided by Aladdin Plumbing Corp.

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