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: One Fixture or More?
Single Fixture Diagnostic Table
Common Causes
How to Fix It
When to Call a Pro
FAQs
Next See
If hot water works everywhere else in your home but not at one fixture, your water heater is almost certainly fine. The issue is localized to that faucet, shower valve, or nearby plumbing.
Important: If multiple fixtures in your home have no hot water, the problem is likely your water heater. See No Hot Water for full troubleshooting.
Quick Answer
No hot water at a single fixture is usually caused by a worn cartridge, faulty mixing valve, anti-scald setting, clogged aerator, or a partially closed shutoff valve.
Start Here: One Fixture or More?
Confirm whether the problem is isolated or system-wide.
- Only one fixture affected: Local plumbing issue
- Multiple fixtures affected: See No Hot Water
Single Fixture Diagnostic Table
Use this table to identify the likely cause based on what you observe.
| 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 flow | Clogged aerator or valve | Clean fixture |
| Problem started after repair | Valve partially closed or debris | Check shutoffs |
Common Causes
Problems affecting a single fixture are almost always caused by components within that fixture or its immediate plumbing connections.
Faulty cartridge
A worn or clogged cartridge can block or restrict hot water flow inside a faucet or shower valve.
Mixing valve problem
Shower valves blend hot and cold water. If the valve fails, hot water may not reach the fixture.
Anti-scald setting
Many shower valves include a temperature limit. If set too low, hot water may be restricted.
Partially closed shutoff valve
The hot water shutoff under a sink may not be fully open, limiting flow.
Clogged aerator or debris
Mineral buildup or debris can block small passages in faucets and restrict hot water.
How to Fix It
Most single-fixture problems can be fixed with basic tools and replacement parts.
- Replace the faucet or shower cartridge
- Adjust or replace the shower mixing valve
- Open shutoff valves fully
- Clean or replace the aerator
- Flush debris from the fixture
For more detailed fixes, see:
When to Call a Pro
Call a professional if the issue goes beyond basic fixture repairs.
- You cannot access or remove the valve
- Problem persists after replacing parts
- Multiple fixtures begin failing
- You suspect hidden plumbing issues
FAQs
Why do I have hot water everywhere except one faucet?
This is usually caused by a faulty cartridge, valve, or clogged aerator in that fixture.
Why does my shower have no hot water but the sink does?
The issue is typically with the shower’s mixing valve or anti-scald setting.
Do I need to replace my water heater?
No. If only one fixture is affected, the water heater is not the problem.
Can a faucet or valve block hot water?
Yes. Internal components can fail or become clogged, restricting hot water flow.
