Water Heater Not Heating: Troubleshooting Guide for Electric & Gas Units

If your water heater suddenly stops producing hot water, the cause is usually simple to identify. Whether you have an electric or gas unit, this guide walks you through the most common issues and the exact steps to fix them.

1. Check the Power Supply (Electric Water Heaters)

Verify the breaker is not tripped.
Reset the water heater’s high-limit switch (usually under the upper access panel).
Inspect wiring connections for signs of burning or loose terminals.

For electrical troubleshooting, see:
Breaker Keeps Tripping

2. Inspect the Heating Elements (Electric)

Electric water heaters use two heating elements. If one fails, water may be lukewarm or cold.

Turn off power at the breaker.
Remove access panels and insulation.
Use a multimeter to test for continuity.
Replace any failed elements.

3. Check the Thermostats (Electric)

Each heating element has its own thermostat. Incorrect settings or failed thermostats can stop heating.

Ensure both thermostats are set to 120–130°F.
Test for continuity if the unit still won’t heat.

4. Check the Pilot Light (Gas Water Heaters)

If the pilot light goes out, the burner won’t ignite.

Remove the access cover.
Look for a flame — if it’s out, relight according to the manufacturer’s instructions.
If it won’t stay lit, the thermocouple may be faulty.

5. Inspect the Gas Supply (Gas)

Ensure the gas valve is fully open.
Check for gas odors — if detected, leave the home and call your gas provider.

6. Look for Sediment Buildup

Over time, sediment collects at the bottom of the tank and reduces heating efficiency.

Drain 2–3 gallons from the tank.
If water is cloudy or sandy, flush the entire tank.

7. Check for Leaks

Leaks reduce pressure and prevent proper heating.

Inspect around the tank base.
Check fittings, valves, and the T&P relief valve.

8. When to Call a Professional

Call a plumber if you notice:

Burning smells
Repeated pilot light failures
Water leaking from the tank itself
No hot water after all troubleshooting steps