If only one faucet or shower has no hot water, the problem is usually a faulty valve, cartridge, or local plumbing issue—not the water heater.
Quick Answer
Start Here: Is It One Fixture?
Single Fixture Diagnostic Table
Common Causes
Shower Problems
Faucet Problems
How to Fix It
When to Call a Pro
Next Steps & Related Guides
FAQs
If hot water works everywhere else in your home but not at one fixture, your water heater is almost certainly fine. The issue is usually localized to that faucet or shower.
Quick Answer
If only one fixture has no hot water, the cause is usually a clogged or faulty cartridge, mixing valve problem, anti-scald setting, or a partially closed shutoff valve.
Start Here: Is It One Fixture?
- Only one faucet or shower affected: Local plumbing issue
- Multiple fixtures affected: See No Hot Water
Single Fixture Diagnostic Table
| What you notice | Likely cause | What to check |
|---|---|---|
| No hot water at one faucet | Faulty cartridge | Replace cartridge |
| No hot water in shower | Mixing valve or anti-scald setting | Inspect shower valve |
| Low hot water only | Clogged aerator or valve | Clean fixture |
| Problem started after repair | Valve partially closed or debris | Check shutoffs |
Common Causes
Faulty faucet cartridge
A worn or clogged cartridge can block hot water flow.
Shower mixing valve problem
A defective mixing valve may prevent hot water from reaching the shower.
Anti-scald setting
Many shower valves limit temperature. If set too low, hot water may not come through.
Partially closed shutoff valve
A valve under the sink or near the fixture may not be fully open.
Debris or mineral buildup
Particles can clog small passages in fixtures and restrict hot water.
Shower Problems
- Faulty mixing valve
- Anti-scald limit set too low
- Clogged valve components
Faucet Problems
- Worn cartridge
- Blocked aerator
- Debris in valve
How to Fix It
- Replace the faucet cartridge
- Adjust or replace the shower mixing valve
- Open shutoff valves fully
- Clean aerators and fixtures
When to Call a Pro
- You cannot access or repair the valve
- Problem persists after basic fixes
- Multiple fixtures begin failing
Next Steps & Related Guides
FAQs
Why do I have hot water everywhere except one faucet?
This is usually caused by a faulty cartridge or valve in that fixture.
Why does my shower have no hot water but the sink does?
The issue is likely with the shower’s mixing valve or anti-scald setting.
Can a faucet block hot water?
Yes. Internal components can fail or become clogged.
Do I need to replace the water heater?
No. If only one fixture is affected, the water heater is not the problem.
