When your water heater pilot light keeps going out, you’re facing a frustrating problem that can leave you without hot water. This issue typically means there’s a safety mechanism preventing the pilot from staying lit, or a component needs cleaning or replacement.
Step-by-Step Fixes
Step 1: Wait and Reset
Turn off your water heater completely and wait 10 minutes. This allows any accumulated gas to dissipate safely. After waiting, follow the relighting instructions on your water heater’s label – usually located on the front panel. Hold the pilot button down for 30-60 seconds after lighting to ensure the thermocouple heats up properly.
Step 2: Clean the Thermocouple
The thermocouple is a small metal rod that sits in the pilot flame. Turn off the gas supply first. Use fine-grit sandpaper or steel wool to gently clean the tip of the thermocouple. Remove any white or green corrosion buildup. This simple cleaning solves the problem about 70% of the time.
Step 3: Adjust the Pilot Flame
Your pilot flame should be blue with a small yellow tip, reaching about 1/2 inch over the thermocouple tip. If it’s too small, locate the pilot adjustment screw (usually near the gas control valve) and turn it slightly counterclockwise to increase the flame size. A weak flame won’t heat the thermocouple enough to keep the gas valve open.
Step 4: Check for Drafts
Strong air currents can blow out your pilot light. Look for open windows, doors, or vents near your water heater. Install a draft shield if needed – a simple piece of sheet metal positioned to block air currents works well. This fix is ideal for water heaters in basements or garages.
Step 5: Test the Thermocouple
If cleaning didn’t work, the thermocouple might need replacement. With a multimeter set to millivolts, test the thermocouple while the pilot is lit. You should read between 20-30 millivolts. Anything under 20 millivolts means replacement is needed. Thermocouples cost $10-20 and are available at most hardware stores.
Step 6: Inspect the Gas Control Valve
If all else fails, the gas control valve might be faulty. This is best diagnosed by a professional, but you can check if the valve knob turns smoothly and clicks into each position properly. A sticky or damaged valve won’t maintain proper gas flow to keep your pilot lit.
Likely Causes
Cause #1: Dirty or Failing Thermocouple
The thermocouple acts as a safety device that senses whether the pilot light is on. When covered in soot or corrosion, it can’t generate enough electrical current to keep the gas valve open. Check for white, black, or green buildup on the metal tip. Clean it first, but if your thermocouple is over 5 years old, replacement is often the best solution.
Cause #2: Insufficient Gas Pressure
Low gas pressure prevents the pilot from burning hot enough. You’ll notice the pilot flame appears weak, orange, or barely touches the thermocouple. Check other gas appliances in your home – if they’re also performing poorly, contact your gas company. For isolated water heater issues, the gas control valve might need adjustment or replacement.
Cause #3: Blocked Pilot Tube
Spider webs, dust, and debris can clog the tiny pilot tube over time. The pilot might light initially but won’t stay lit because insufficient gas flows through. Use compressed air to blow out the pilot assembly, or carefully use a thin wire to clear the pilot orifice. This problem is most common in water heaters that haven’t been serviced in several years.
When to Call Expert Help
Call a licensed plumber or HVAC technician immediately if you smell gas after attempting these fixes. Professional help is also recommended when your water heater is over 10 years old, as multiple components might be failing. If you’ve replaced the thermocouple and cleaned everything but the problem persists, the gas control valve likely needs replacement – a job best left to professionals due to gas line connections.
Don’t attempt repairs if your water heater is under warranty, as DIY fixes might void coverage. Most manufacturers require certified technician service for warranty claims in 2025.
Copy-Paste Prompt for AI Help
“My [gas/propane] water heater pilot light won’t stay lit. It’s a [brand and model if known] installed in [year if known]. The pilot lights initially but goes out after [timeframe]. I’ve already tried [list what you’ve attempted]. The pilot flame appears [describe color and size]. Other symptoms include [any unusual sounds, smells, or observations]. What specific troubleshooting steps should I try next, and what safety precautions should I take?”
Remember that fixing a pilot light issue yourself can save you $150-300 in service calls. Most pilot light problems are simple fixes that take under 30 minutes. However, never compromise on safety – if you’re uncomfortable working with gas appliances or smell gas at any point, shut off the gas supply and call a professional immediately.