Signs of a tired shower valve
- Water temperature jumps when someone flushes a toilet
- Handle turns hard or spins without changing temperature
- Shower head drips long after it is shut off
- Water runs from the tub spout and head at the same time
- Stains or soft drywall on the other side of the wall
Rebuild first
Most single-handle valves from major makers use a replaceable cartridge. Swapping it, cleaning scale from the body and fitting a new trim kit often restores the shower completely without touching tile.
When the whole valve goes
- Open the wall from behind, via a closet or a removable panel where possible.
- Cut out the old valve body and install a fresh pressure-balancing or thermostatic valve.
- Solder or crimp new connections and pressure test before closing.
- Fit a trim plate sized to cover the old opening in the tile.
Shower drains too
While a wall is open, it is a good time to check the drain and the trap below. For slow showers, see bathroom drain unclogging. For basement bathrooms, our rough-in page explains valve placement, and faucet repair covers sinks.
The short version
Tell-tale signs
- One tap trickles while the others run fine
- Lever spins loose or grinds to turn
- Wet hose bib or stain behind the washer box
- Spout drips with the lever fully closed
Kit on the van
- Headlamp and a foam pad for under-cabinet work
- Basin wrench and cartridge puller
- Quarter-turn stops and braided connectors
- Tubular trap kits in white plastic and chrome
How we go about it
- Turn the stops on slow and run hot then cold
- Dry every joint with paper and look again in ten minutes
- Shut both stops and open the tap to bleed it
- Strip the fixture and look at seats, seals and threads
Your questions, answered plainly
Do you have to break tile?
Often not; access from behind or through a larger trim plate avoids it.
What is a thermostatic valve?
It holds a set water temperature even as supply pressures and temperatures change.