Quick Answer:
If only one bathroom’s shower has no hot water, start by confirming hot water is available elsewhere in the house. Most often the problem is the shower valve’s temperature limit stop or a misassembled handle that prevents full hot rotation. Check the handle assembly and the limit stop before assuming the cartridge is bad.
Why This Happens
Single-bathroom hot-water loss is usually not a mysterious plumbing curse. Common causes:
- A temperature limit stop or anti-scald setting on the shower valve is set too far toward cold, preventing the handle from accessing hot water.
- The handle or trim was put back on incorrectly after maintenance, so the handle doesn’t move far enough to call for hot water.
- A thermostatic or pressure-balancing valve is damaged or seized and needs repair or replacement.
- Work done recently near the shower can change the setting—see Shower cold after plumbing repair or No hot water after remodel for related situations.
Step-by-Step What to Do
Step 1 — Confirm the issue is limited to one bathroom
- Turn on a hot faucet in another bathroom, the kitchen, or a laundry sink. If those fixtures supply hot water normally, the water heater and house plumbing are likely fine.
- If the whole house lacks hot water, the problem is the water heater or a main supply issue, not the shower valve.
Step 2 — Test the shower carefully
- Turn the shower on and move the handle slowly from cold toward hot while feeling the water temperature. Note whether the handle reaches a point where hotter water should come.
- If the handle doesn’t travel far or feels blocked, it may be hitting the limit stop or an incorrect handle installation.
Step 3 — Check the handle assembly
- Shut off water to the shower if there are local shutoff stops behind the access panel; otherwise be prepared for a short burst when you remove trim. Work gently and keep a towel handy.
- Remove the handle and trim according to the manufacturer’s instructions. Inspect that the handle splines align with the valve stem and that no spacer or index piece is misinstalled.
- Reinstall the handle so it matches the valve stem orientation; an incorrectly rotated handle can limit travel into the hot position.
Step 4 — Locate and adjust the temperature limit stop
- With the trim off you’ll often see a small plastic or metal stop attached to the valve body or a limit screw on the cartridge. This restricts how far the handle can turn toward hot.
- Adjust the limit stop a small amount toward the hot side, reattach the handle, and test the water. Make only small adjustments to avoid scalding.
- If the adjustment works, reassemble trim carefully and test again for consistent hot water.
Step 5 — If adjusting doesn’t fix it
- If you still get no hot water after confirming handle alignment and limit stop, the cartridge or valve may be worn, clogged, or seized and will likely need repair or replacement.
- Keep the plumbing shutoffs accessible and avoid forcing parts that are stuck; forcing can break components and create leaks.
What Not to Do
- Don’t accept “one bathroom only” as mysterious—limit stops are often set wrong and handle assembly errors are common.
- Don’t force a stuck cartridge, pry on fragile trim, or remove internal parts unless you have the right tools and a plan to turn off and isolate water.
- Don’t guess how far to move the limit stop; moving it too far can create a scald risk. If adjustment is unclear, a plumber is appropriate.
When to Call a Professional
- If you can’t identify the limit stop or how to access it safely.
- If removing the trim reveals a seized or damaged cartridge, persistent leaks, or corrosion.
- If you’re uncomfortable shutting off or isolating water, or if adjustments don’t restore hot water—call a licensed plumber to inspect and replace valve parts as needed.
Safety Notes
- Adjust temperature limits slowly and test briefly to avoid scalding. Always run the water at a safe distance from skin when testing hotter settings.
- Shut off water to the fixture before removing internal parts where possible. If you must work with the water on, keep towels and a bucket ready and work carefully.
- If you smell gas, hear running water you can’t stop, or see active leaks, stop work and call an emergency professional immediately.
Common Homeowner Questions
- Why does one shower lose hot water but all other taps are fine?
Most often a limit stop, handle alignment, or a single valve problem in that shower, not the water heater. - Can I fix the limit stop myself?
Yes, if you can access the trim and feel comfortable making small adjustments; if unsure, call a plumber. - Will replacing the cartridge always fix it?
Not always—first confirm handle and limit stop. If the cartridge is worn or stuck, replacement usually resolves temperature control issues.
For more related articles, see the No Hot Water at Shower but Everywhere Else hub.