Gas water heater repair
A gas water heater that won't stay lit usually has a worn thermocouple or flame sensor, the part that tells the gas valve the pilot is lit. Other common repairs are a dirty burner or pilot assembly, a failed gas control valve, and venting problems.
Gas heaters heat water with a burner under the tank and vent combustion gases out through a flue. Most repairs involve the parts that light and monitor that flame.
Any gas smell changes the order of operations: leave the house and call the gas utility from outside before anyone works on the heater.
Signs you need gas water heater repair
- Pilot goes out or won't stay lit
- No hot water
- Yellow or uneven burner flame
- Soot around the burner or flue
- Gas smell (leave and call the gas utility)
How gas water heater repair is done
- 1
Check gas and safety
Confirm gas supply, venting and no leaks.
- 2
Diagnose ignition
Test the thermocouple or flame sensor, igniter and gas valve.
- 3
Repair and verify
Replace the failed part, clean the burner if needed and check the flame and draft.
What affects the cost of gas water heater repair
- Thermocouple vs. gas control valve
- Venting corrections
- Tank age and condition
Ask for the trip fee and the total price before work starts.
Gas water heater repair: what you can do yourself
Safe to try
- • Relight the pilot following the label instructions
Stop and call if
- • You smell gas
- • The pilot won't stay lit after relighting
- • There's soot or scorching around the burner
Need gas water heater repair? Call now
SteadWell is a free referral service, not a plumbing company. Calling (833) 753-0180 connects you with an independent, licensed plumber who serves your ZIP code; the plumber quotes and performs the work. Calls may be recorded.
Gas water heater repair: common questions
Why does my gas water heater pilot keep going out?
Most often a worn thermocouple or flame sensor. Drafts, a dirty pilot assembly and venting problems are other causes.
How much does thermocouple replacement cost?
Cost guides list it at roughly $150 to $300 nationally, parts and labor. National estimates, not quotes.
Is a gas control valve worth replacing on an old heater?
On a heater near or past 10 years old, the cost of a valve often makes replacement the better value.