How to Relight a Gas Water Heater Pilot Light (Step-by-Step)

TL;DR: Most gas water heater pilot lights go out because of a draft, a faulty thermocouple, or a temporary gas supply interruption. Relighting takes 5 minutes if you follow the label on the control panel, wait 10 minutes for residual gas to clear, and hold the pilot button for 30-60 seconds after the flame catches. If the pilot won't stay lit after two attempts, the thermocouple likely needs replacement — a $15 part that most plumbers install for under $200.

_Last reviewed: July 2026 · 6 min read_

You turn on the tap and the water is cold. The water heater is on, the gas line is open, but there's no flame in the sight glass. A gas water heater pilot light can go out for a few specific reasons, and relighting it is straightforward if you know the sequence. This guide walks through the steps, the safety checks, and when to stop and call a professional.

Okoniq Property Hub logs every pilot relight, thermocouple replacement, and annual water-heater flush so you have a service history when you sell or when the next outage happens.

Why did the pilot light go out?

Three causes account for nearly every pilot outage: a draft (wind blowing down the flue or through a nearby window), a failing thermocouple (the safety sensor that tells the gas valve the pilot is lit), or a temporary interruption in the gas supply (utility work, meter swap, or someone accidentally closing the gas shutoff). Older water heaters — those 10+ years old — are more prone to thermocouple drift because the sensor tip corrodes or shifts out of the pilot flame. If you smell gas near the water heater, do not attempt to relight; leave the house, call the utility, and let them check for a leak. Most pilot outages happen without a leak, but the smell test is mandatory before you touch any controls.

What do you need before you start?

You need a long-reach lighter (a barbecue lighter or fireplace match), a flashlight, reading glasses if the instruction label is small, and 15 minutes of uninterrupted time. Clear the area around the water heater so you can kneel or crouch without bumping a shelf or hot pipe. If the water heater is in a closet, open the door wide and make sure the room is ventilated. Check that the gas shutoff valve on the pipe leading to the heater is in the open position (handle parallel to the pipe). Some models have a dedicated pilot-light access panel at the base; others show the pilot through a small sight glass. Locate the control panel — usually a dial with settings for "Off," "Pilot," and "On" or temperature numbers — and find the red or black reset button nearby. The manufacturer's label on the tank side lists the exact sequence; read it once before you start.

How do you relight the pilot?

Turn the control dial to "Off" and wait 10 minutes. This lets any residual gas dissipate. After 10 minutes, turn the dial to "Pilot." Press and hold the pilot button (sometimes labeled "Reset" or integrated into the dial) while you use the long lighter to ignite the pilot burner. You'll see a small flame appear through the sight glass or access opening. Keep holding the pilot button for 30 to 60 seconds after the flame catches — this heats the thermocouple enough to signal the gas valve to stay open. Release the button slowly. If the pilot stays lit, turn the dial to "On" or your desired temperature setting. The main burner should ignite within a few seconds. If the pilot goes out as soon as you release the button, wait 5 minutes and try again, this time holding for a full 60 seconds. If it goes out a second time, the thermocouple is likely the problem. When you're tracking recurring pilot issues, logging each event in Okoniq gives you a timeline that helps a plumber diagnose intermittent faults faster.

When should you call a plumber instead?

If the pilot won't stay lit after two attempts, or if you smell gas during the process, stop and call a licensed plumber. A thermocouple replacement costs $15 to $30 for the part and typically $100 to $200 in labor; most plumbers can do it in 30 minutes. If the gas valve itself is faulty — indicated by no gas flow even when the valve is open and the pilot button is pressed — replacement runs $300 to $500 including labor. Water heaters older than 12 years with frequent pilot outages are often better candidates for full replacement than repeated repairs; a new 40-gallon gas unit installed costs $800 to $1,500 depending on local codes and venting requirements. If you're also dealing with water leaks or rust stains near the base, read about diagnosing ceiling water stains for leak-tracing principles that apply to any plumbing fixture. For homes with cast-iron drain stacks near the water heater, check for corrosion patterns that might coincide with high humidity or condensation issues.

How do you prevent future pilot outages?

Install a draft guard or chimney cap if the flue terminates on the roof in a windy area; most HVAC supply stores carry adjustable caps for under $50. Keep the water heater area clear of boxes, paint cans, and clutter so airflow remains steady. Inspect the thermocouple annually during your boiler or furnace maintenance cycle — look for white corrosion on the tip or a bent position that moves the sensor away from the pilot flame. If you notice the pilot flickering even when it stays lit, that's a sign of insufficient gas pressure or a partially clogged pilot orifice; a plumber can clean or replace the orifice in the same visit as a thermocouple swap. Document every relight and every service call in Okoniq so the next technician sees the pattern and can recommend a permanent fix instead of another temporary patch.

FAQ

How long should I hold the pilot button when relighting?

Hold it for 30 to 60 seconds after the flame appears. This gives the thermocouple time to heat up and signal the gas valve to keep the pilot line open. Releasing too soon is the most common reason a pilot goes out immediately.

Is it safe to relight the pilot myself?

Yes, if you follow the manufacturer's label, wait 10 minutes after turning the control to "Off," and do not smell gas. If you smell gas or if the pilot won't stay lit after two attempts, stop and call a plumber.

How much does a thermocouple replacement cost?

The part costs $15 to $30; most plumbers charge $100 to $200 total including labor. Installation takes 20 to 30 minutes.

Why does the pilot keep going out every few weeks?

Repeated outages usually mean a failing thermocouple, a draft blowing down the flue, or low gas pressure. A plumber can test gas pressure, inspect the flue, and replace the thermocouple in one visit.

Can I use a regular lighter instead of a long-reach lighter?

You can, but the pilot burner is often recessed 4 to 6 inches inside the access opening. A barbecue lighter or fireplace match keeps your hand farther from the flame and makes the job easier.

This is educational information, not plumbing or safety advice. If you smell gas, leave the house and call your utility company's emergency line. Consult a licensed plumber for thermocouple replacement, gas-valve repairs, or any situation where the pilot will not stay lit.