Gas Valve & Thermocouple Replacement Cost
On a gas tank, a pilot that won’t stay lit is usually a cheap thermocouple; a dead unit can be a pricier gas control valve. Enter the part and labor to price either — gas work is a pro job.
1 Enter your numbers
A pilot that won’t stay lit is often a cheap thermocouple; a failed gas control valve is pricier — about $187 here. Gas work is a licensed plumber / gas fitter job; this only estimates the cost.
Two gas-side parts cause most “no hot water” calls on a gas tank, and they sit at opposite ends of the price range. The thermocouple (or, on newer units, the thermopile / flame sensor) is a $10–$30 safety probe: if the pilot flame is not sensed, it shuts the gas off. A pilot that lights but won’t stay lit is the classic sign it has failed — a cheap part, mostly labor.
The gas control valve is the pricier failure: $100–$300 for the part and a similar labor line, so the job runs several hundred dollars. It is the brain of the burner. Because a gas valve replacement can approach a meaningful fraction of a new tank, weigh it against the unit’s age — a big gas-valve bill on an old tank often tips toward replacement. Set the part input to about $20 to price a thermocouple, or about $150 for a gas valve.
Formula
total = (part + labor) × (1 + contingency%)
Same arithmetic, two very different parts: enter ~$20 for a thermocouple or ~$150 for a gas control valve. The contingency covers diagnosis time — a pilot fault can also be a dirty pilot orifice or a bad gas valve, and telling them apart takes a pro.
Worked example
Thermocouple: part $20, labor $150, 10% buffer → (20 + 150) × 1.10 = $187.
Gas control valve: part $150, labor $200, 10% buffer → (150 + 200) × 1.10 = $385.
So the same complaint — no hot water — is a $187 fix or a $385 fix depending on which part failed. Get it diagnosed before you commit, and on an aging tank compare the gas-valve figure to a full replacement.
Thermocouple or gas valve? The price hinges on it
Check first. A pilot that won’t stay lit points to the thermocouple; no pilot / no ignition at all or erratic burner behavior points to the gas control valve. A dirty pilot orifice can mimic a bad thermocouple, so a good diagnosis saves a wasted part.
Safety — non-negotiable. Gas work is a licensed plumber / gas fitter job. Do not improvise on a gas valve, gas line, venting or combustion air, and if you ever smell gas, leave and call the utility. This tool estimates cost only; it is not a repair procedure or a combustion/venting sign-off.
Reference table
LABELED planning typicals — the part and the labor on your job come from your own quote. Notice the pattern: on most repairs the part is cheap and the labor (the service call) is the real cost, so the biggest lever is whether a trip charge and a minimum apply.
| Repair | Typical part | Typical labor | Common symptom |
|---|---|---|---|
| Heating element (electric) | $10–30 | $150–300 | No / not enough hot water |
| Thermostat | $20–40 | $150–250 | Water too hot, too cold or swinging |
| Anode rod (preventive) | $20–60 | $100–200 | Rotten-egg smell, rusty water |
| Temperature & pressure (T&P) valve | $15–40 | $120–250 | Valve dripping or weeping |
| Thermocouple (gas) | $10–30 | $100–200 | Pilot won’t stay lit |
| Gas control valve | $100–300 | $150–300 | No ignition / no gas |