Symptoms
- Kitchen and bathroom sinks have hot water
- Shower stays cold or lukewarm no matter the handle position
- Problem started suddenly
- Handle turns fully but temperature doesn't change much
Likely causes
- CommonScald-guard limit stop set too lowMany valves have an adjustable stop that caps how far the handle turns toward hot.
- CommonFailed or clogged cartridge blocking hot water flowA stuck or scaled cartridge can restrict the hot side while letting cold through fine.
- PossibleClosed or partly closed hot water stop valveSome shower valves have small integral shutoffs that can get bumped or partially closed.
- Less commonCrossed supply lines during a repairIf someone recently worked on the plumbing, hot and cold could be swapped or miswired.
What to do
- Confirm hot water works fine at the nearest sink to rule out a water heater issue.
- Turn off water to the shower and remove the handle and trim plate to access the valve.
- Look for a small plastic rotational limit stop behind the handle; if present, rotate it to allow more hot water travel.
- Pull the cartridge and inspect for scale or debris blocking the hot water port.
- Clean or replace the cartridge if it looks worn, cracked, or heavily scaled.
- Check for any small integral shutoff screws on the valve body and make sure they're fully open.
- Reassemble, turn water back on, and test at both hot and cold extremes before restoring the limit stop.
Tools and parts
- Screwdriver
- Adjustable wrench
Shower valve cartridgeSearch: “shower faucet cartridge replacement”
When to call a pro
Call a plumber if you find crossed lines or the valve body itself looks damaged.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.