First: if you smell gas, leave
A gas smell near the heater is a rotten-egg odor. Don't flip switches or relight anything. If you smell gas, leave the house first. From outside, call 911 and Atmos Energy's emergency line, 866-322-8667. Once the utility says the house is safe, call a plumber for the repair. For anything else that can't wait, the emergency plumbing page explains what counts.
Why the pilot keeps going out
On older-style heaters, a pilot that won't stay lit is usually one of:
- A worn thermocouple. The thermocouple is a small probe that sits in the pilot flame and generates the millivolts that hold the gas valve open. When it weakens or gets coated, the valve snaps shut soon after you release the button. It's an inexpensive part and a common repair.
- A dirty or misaligned pilot opening. A weak, yellow, wandering flame won't heat the thermocouple properly.
- Drafts or a venting problem. Air moving down the flue can blow the pilot out repeatedly. That one matters — bad draft can mean exhaust isn't leaving the house, and it needs a real diagnosis, not another relight.
Newer heaters use a sealed combustion chamber with an electronic igniter instead of a standing pilot. On those, a failed igniter or flame sensor produces the same symptom: the burner clicks, lights, and shuts back down.
Other common gas heater failures
- No hot water at all: gas supply turned off after other work, a failed gas control valve, or an air lock in the gas line.
- Water not hot enough: the thermostat dial on the control valve, or heavy sediment insulating the tank bottom.
- Burner fires in odd cycles: sediment popping, or a thermostat drifting out of calibration.
- Water pooling at the base: if it's from a fitting or the relief valve, that's repairable; if it weeps from the tank seam, the tank is done and you're into water heater replacement territory.
- Relief valve dripping: that valve is protecting the tank from pressure or temperature that's too high. Never plug it; it needs diagnosis.
What the repair involves
The plumber shuts off gas and water, takes out the burner assembly, and works down a checklist: flame quality, thermocouple or flame sensor output, gas control valve, venting draft, and the relief valve. Parts like a thermocouple or burner assembly are same-visit repairs on most models. Control valves are ordered by model number, which is one more reason to photograph the label before calling. After any repair, the plumber leak-tests the connections with a soap solution and confirms the draft is pulling exhaust up the flue.
What affects the price
The age and brand of the heater (parts for common brands are on the truck; obscure ones get ordered), which part failed, whether the flue needs work, and whether the heater is in a crawlspace or closet that's hard to reach. Diagnosis and the price of the fix come before any work starts — ask for both.
Is it safe to relight the pilot myself?
Relighting per the instructions printed on the heater is reasonable if there's no gas smell and the pilot went out once. If it's gone out repeatedly, won't light at all, or the flame looks lazy and yellow instead of blue, stop relighting — each failed attempt is telling you something, and on a gas appliance the something is worth a professional look. Repeat pilot failures, soot around the burner door, or rust flakes at the base of the tank all point toward the broader water heater repair decision: fix the part or replace the heater.
Johnson City notes
Gas water heaters are common in Johnson City's older neighborhoods and in houses throughout Washington County where natural gas service reaches; where it doesn't, many homes run propane heaters that work on the same principles but need the tank's propane supplier for fuel-side issues. Cold snaps are hard on gas heaters the same as any other: the burner runs far longer against cold inlet water, and marginal parts tend to quit during the first hard week of January. If your heater is over ten years old and gives you its first trouble in winter, weigh the repair against replacement before spending much on parts.