A water heater that won't stay lit is frustrating and inconvenient. Whether it's leaving your family without hot water in the morning or causing repeated relighting, a pilot light problem can be a sign of underlying issues. Understanding the root causes is essential to fix it safely and efficiently.
How a Pilot Light Works
The pilot light is a small flame that ignites the main burner of your water heater. In older gas water heaters, this tiny flame burns continuously, ensuring that hot water is available whenever needed. Modern water heaters may use electronic ignition systems, which operate differently but can experience similar issues with inconsistent lighting.
Common Causes of a Pilot Light Going Out
- Dirty pilot orifice – soot and debris can block gas flow, causing the flame to fail.
- Faulty thermocouple – this safety device may fail to detect the flame, shutting off gas supply.
- Drafts or airflow issues – nearby vents, fans, or open doors/windows can extinguish the pilot.
- Low gas pressure – inadequate gas supply prevents the pilot from staying lit.
- Faulty gas control valve – aging or malfunctioning valves may intermittently stop gas flow.
Check for Drafts and Vent Issues
Drafts are one of the most common reasons a pilot light fails. Even small gusts of wind can blow out the flame. Ensuring the area is protected and the venting system is functioning properly is crucial.
- Inspect windows, doors, or vents near the water heater.
- Ensure the water heater is in a closed, protected space away from airflow disturbances.
- Check the vent pipe for obstructions, debris, or corrosion.
Clean the Pilot Orifice
Dirt, soot, or spider webs can partially block the pilot orifice. Cleaning it allows the gas to flow freely and the flame to stay lit.
- Turn off the gas supply before touching the pilot assembly.
- Remove the pilot assembly if your model allows.
- Use compressed air or a soft brush to remove dirt and debris.
- Reassemble and relight following the manufacturer's safety instructions.
Inspect or Replace the Thermocouple
The thermocouple acts as a safety device, detecting the flame and signaling the gas valve to stay open. If the thermocouple is worn or misaligned, it can shut off gas even if the pilot is burning correctly.
- Turn off the gas supply.
- Locate the thermocouple near the pilot light.
- Check for corrosion, damage, or loose connections.
- Replace the thermocouple if necessary, using the correct model for your water heater.
Check Gas Pressure and Control Valve
Low gas pressure or a failing gas control valve can prevent the pilot light from staying lit. It's important to ensure your home has proper gas flow and that the control valve is functioning correctly.
- Locate the gas shutoff valve and ensure it is fully open.
- Inspect for leaks using a soapy water solution around connections.
- Test gas pressure if you have a manometer, or call your gas company for assistance.
- Replace the gas control valve if it shows signs of wear or malfunction.
Reignite the Pilot Light Safely
Once all parts are cleaned, adjusted, or replaced, relighting the pilot light must be done carefully to avoid accidents.
- Turn the gas knob to "pilot."
- Press and hold the knob while using a long lighter or match to ignite the pilot.
- Hold the knob for 30–60 seconds to ensure the thermocouple senses the flame.
- Release the knob slowly; if the flame stays lit, return the gas knob to "on."
- Observe the pilot for a few minutes to confirm stability.
Preventive Maintenance Tips
- Clean the pilot assembly every 6 months to prevent soot buildup.
- Inspect the thermocouple annually and replace if worn.
- Ensure your water heater is in a draft-free, ventilated area.
- Flush the water heater tank periodically to reduce sediment that can affect heating efficiency.
- Check gas pressure annually or whenever the pilot light starts failing repeatedly.
Safety Precautions
Important Safety Guidelines:
- • Always turn off the gas supply before attempting repairs.
- • Never use open flames near gas leaks.
- • Ensure proper ventilation while inspecting or working on a water heater.
- • Use manufacturer-approved replacement parts only.
- • If unsure, call a licensed plumber instead of attempting DIY fixes that could risk gas leaks or fire hazards.
Signs You Need a Professional Plumber
- Pilot light keeps going out despite cleaning and thermocouple replacement.
- Gas control valve shows wear or failure signs.
- Strong smell of gas or visible leaks near the water heater.
- Repeated low gas pressure or flame instability.
- Multiple water heater issues occurring at the same time, such as noisy operation, leaking, or rust.
Interactive FAQ
Maintaining your water heater properly ensures that your pilot light stays lit, your home has reliable hot water, and you avoid costly repairs. Regular inspection, cleaning, and preventive maintenance are key to long-term performance and safety.