What it isGas water heaters use a burner beneath the tank and a flue that runs up through the center to vent combustion gases outside. Most failures involve the pilot or ignition system, the gas control valve, or venting. Because combustion and carbon monoxide are involved, venting and gas work should be handled by a qualified professional.
When you need gas water heater repair
- Pilot will not light or stay lit
- Burner flame is yellow, lazy or noisy
- Soot or scorching near the burner door
- Exhaust smell or a carbon monoxide alarm
- Water not hot enough with the burner running
How it works
- Check gas supply and the gas control valve settings.
- Inspect and replace the thermocouple or flame sensor, igniter, or pilot assembly as needed.
- Clean the burner and check flame quality.
- Test draft at the draft hood and inspect the vent connector and flue.
- Check the flammable vapor sensor on newer models.
Limits and when it’s not the right fix
- Venting defects can require changes beyond the heater itself.
- Some newer gas controls are replaced as a unit.
What affects the cost
We don’t publish national price figures because real quotes vary too much by region, access and the condition of your system. These are the factors that move the price:
- Component replaced
- Venting corrections
- Model-specific parts
- Combustion air issues
Ask for a written quote that names the method, materials and any permit or restoration work before work begins.
Gas Water Heater Repair: common questions
Why won't my water heater pilot stay lit?
A worn thermocouple or flame sensor is the most common reason, followed by a dirty pilot tube, a faulty gas control, or poor combustion air. Newer heaters may lock out after a flammable vapor sensor trips.
Is a yellow flame on a water heater dangerous?
A yellow, lazy flame usually means incomplete combustion, which can produce carbon monoxide. Have it checked, and make sure you have working CO alarms.
What should I do if I smell gas near my water heater?
Leave the building, do not use switches or phones inside, and call your gas utility or 911 from outside.
