Water Heater Pilot Light: Why It Keeps Going Out
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When a water heater pilot light keeps going out, most homeowners feel stuck between frustration and worry. I get it. At Clog Heroes Plumbing, Sewer & Drain, we’ve answered countless calls from people who wake up to cold water and no clue why their pilot light won’t stay on. And while it can definitely feel like a major issue, the cause is usually something simple once you know what to look for.
Below, I’ll walk you through the most common reasons this happens, how we troubleshoot the problem, and when it’s time to bring in a pro.
How a Water Heater Pilot Light Works
Understanding the basics helps you figure out why things go wrong. Your pilot light is a small flame that stays lit so your burner can ignite when the tank needs heat. A thermocouple sits next to the flame, sensing heat and allowing gas to flow only when the flame is present. If anything interrupts that process, the system shuts down for safety.
When the flame isn’t stable, your water heater may take longer to recover between cycles. If you’re unsure what a normal heat-up time looks like, our guide on how long it takes a water heater to heat up can help you understand what’s typical for most systems.
These parts are tiny, but when one fails, your water heater can’t stay running.
Common Reasons Your Water Heater Pilot Light Won’t Stay Lit
The most common issue we see is a weak or dirty thermocouple. When the thermocouple can’t sense the flame, it shuts the gas off for safety. Another common problem is a clogged pilot tube, which restricts the flame so much that it flickers out.
Sometimes, though, it’s just a draft. A quick gust through a basement or utility room can blow out a weak flame in seconds.
Drafts Can Blow Out a Water Heater Pilot Light
Even small airflow changes can push the flame off the tip of the pilot tube. And once the flame loses contact, the thermocouple shuts everything down. This can happen near doors, windows, vents, or during seasonal temperature shifts inside the home.
For homeowners in colder climates, drafts often increase as winter approaches. A simple fix may involve adjusting the unit’s ventilation or blocking a direct airflow path — something our team handles often at Clog Heroes Plumbing, Sewer & Drain.
If you want seasonal safety tips, Ready.gov shares helpful home-heating guidance.
Gas Supply Problems That Cause Repeated Pilot Light Failures
Another reason a pilot keeps going out is inconsistent gas supply. This can happen if:
The gas valve is partially closed
There’s a supply interruption
The control valve inside the heater is malfunctioning
If the flame looks weak or won’t stay lit, the pilot may not be getting enough fuel to remain stable. NFPA data shows that nearly half of all home-heating fires occur between December and February, which is why gas-related heating issues should be addressed quickly during colder weather. Even small fuel-flow problems can get worse in winter, especially if the system is already under strain.
Dirty Components Can Affect the Water Heater Pilot Light
Dirt, dust, and debris are more powerful than people think. A small amount inside the pilot tube or burner assembly can change flame shape and stability. When the flame shrinks or lifts off the pilot tip, the system shuts down for protection.
Regular maintenance helps prevent this, especially if the heater is in a garage, attic, or utility closet with more dust circulation.
How Clog Heroes Diagnoses a Failing Water Heater Pilot Light
Every system has a different setup, so we check more than just the flame. During a typical service call, we:
Inspect the thermocouple
Clean the burner and pilot assembly
Test gas pressure
Check for drafts and ventilation issues
Examine the gas control valve
Look for corrosion or rust around key parts
These small checks prevent bigger problems later. While homeowners can relight a pilot themselves, diagnosing repeated outages is usually better handled by a pro.
When It’s Time to Call a Professional
If you’re relighting the pilot every day—or the flame won’t stay lit at all—something deeper is going on. Gas components need careful handling, and repeated failures can signal a thermocouple issue, gas pressure problem, or failing control valve. At Clog Heroes Plumbing, Sewer & Drain, we troubleshoot these issues daily and help prevent long-term damage.
If you ever do need to turn the heater off—like if you smell gas or something doesn’t look right—our guide on how to turn off a water heater safely in any home can walk you through the right steps.
If you’re dealing with a stubborn flame or inconsistent hot water, contact us today and we’ll take care of it.
Summary
A water heater pilot light that won’t stay lit is frustrating, but it’s usually fixable once you know the cause. Whether it’s a draft, a dirty pilot assembly, weak thermocouple, or gas flow issue, a quick inspection gets everything back to normal. And when you need help, Clog Heroes Plumbing, Sewer & Drain is always ready to get your hot water back on track in Fredericksburg and the surrounding areas.
Commonly Asked Questions About Water Heater Pilot Lights
Here are a few quick answers to the questions homeowners ask most about pilot lights.
It shouldn’t go out often. If it keeps happening, something is blocking gas flow, creating a draft, or affecting the thermocouple. Cold air can create stronger drafts, which may blow out the flame, especially in basements or garages. Yes, if the manufacturer allows it and there’s no gas smell. If you’re unsure, it’s safer to call a professional. A weak or discolored flame often points to dirt in the pilot tube or a gas supply issue.How often should a water heater pilot light go out?
Can cold weather affect my pilot light in places like Fredericksburg?
Is it safe to relight a pilot light myself?
Why does my pilot light look weak or yellow?