Shower problems are almost always valve problems. The showerhead rarely fails — what fails is the mixing valve behind the wall that balances hot and cold, the diverter that sends water from tub spout to showerhead, or the supply lines feeding the valve. Because the working parts are inside the wall, shower repair gets misdiagnosed as "low water pressure" when the real cause is a cartridge clogged with mineral scale or a pressure-balance spool that's stuck.
What we repair
- Temperature swings — a shower that goes cold when someone flushes a toilet, or scalding when a cold tap opens elsewhere. This is a failing pressure-balance valve, and it's both a comfort problem and a safety one.
- Stuck or leaky diverters — the tub-shower diverter that won't send water to the showerhead, or leaks water down the spout while you shower, cutting flow.
- Low shower pressure — often a clogged showerhead or a restricted cartridge, not a building-wide pressure issue. We diagnose before recommending anything invasive.
- Dripping showerheads — a shower valve that doesn't fully close, usually a worn cartridge or seat.
- Hard-to-turn handles — mineral buildup in the valve stem, common in buildings with hard water.
- Thermostatic valve calibration — a valve that no longer holds the set temperature within a couple of degrees.
Repair or replace the valve?
Most shower valves are repairable by replacing the cartridge — the internal module that does the mixing and balancing. We carry common cartridges for the brands used in Manhattan apartments and can usually replace one without opening the wall. A valve body that's cracked or corroded, or an obsolete valve for which cartridges are no longer made, is a full valve replacement. That's a bigger job because it requires access behind the wall, but it's also the chance to install a modern pressure-balance or thermostatic valve that solves the temperature-swing problem permanently.
Installation and renovation work
For new shower installs and bathroom renovations, we handle the rough-in: positioning the valve at the right height, setting the shower arm and head, running supply lines sized for the fixture's flow rate, and pressure-testing before the tile goes on. In prewar bathrooms we often find the old shower was plumbed with supply lines too small for a modern high-flow showerhead — upgrading the supply run is what turns a disappointing new shower into one that actually performs. We coordinate with tile and waterproofing so the wall goes back correctly around the valve.
A shower valve that fails behind the wall can leak into the wall cavity — if you see a stain on the wall below or beside the shower, that's leak repair territory and worth catching early. For the simpler faucet and sink work in the same bathroom, see faucet repair & installation. And if a shower valve fails while you have no other working hot water, check whether the water heater itself is the cause — water heater services sorts that out.