Lighting a gas water heater pilot safely is a common homeowner maintenance task. This guide explains how to light a standing-pilot or intermittent-ignition water heater, what tools you need, and how to troubleshoot common issues using a lighter or the built-in igniter. Readers will learn best practices, safety precautions, and when to call a professional.

Identify Your Water Heater Type

Water heaters typically fall into two main categories: standing-pilot models and intermittent-ignition models. Standing-pilot units have a permanently lit pilot flame that relights the main burner when needed. Intermittent-ignition models use an electronic igniter or spark mechanism to light the burner without a pilot flame. Knowing your type guides the lighting procedure and safety steps. Check the instruction tag on the heater or the manufacturer’s manual for the exact model and recommended procedure.

Tools And Safety Gear You May Need

Long-reach lighter or match safely extending from a distance
Non-slip work gloves to protect hands
Protective eye wear to guard against small flare-ups
Flashlight to inspect the burner and venting area
Screwdriver or flashlight for accessing the front panel if required
CO detector in the home to monitor for combustion gases

Before any lighting attempt, ensure proper ventilation. Gas odors, hiss sounds, or smoke indicate immediate danger. If you smell gas strongly or hear a hissing sound, evacuate the area and contact the gas utility or emergency services.

Preparing The Water Heater

Preparation steps help ensure a safe lighting process. Turn the thermostat to a low setting to prevent overheating once the burner lights. Turn off the gas supply or set the valve to Off, then wait a few minutes to disperse any accumulated gas. If your heater has a standing pilot, you will need to locate the pilot assembly near the bottom front of the unit behind the access panel. For intermittent-ignition models, locate the control knob and igniter area.

Lighting A Standing-Pilot Water Heater

For standing-pilot models, follow these steps in order:

Open the front panel and confirm the gas control knob is set to Off.
Turn the knob to Pilot. Press and hold the knob in to keep the gas valve open.
While holding the knob, use a long-reach lighter or match to ignite the pilot flame at the pilot opening. If your unit has a dedicated pilot gas opening, apply the flame directly to it until the pilot lights.
Continue to hold the knob in for about 30 seconds after the pilot lights to heat the thermocouple. Release slowly and check that the pilot flame remains lit.
Turn the knob to On, then adjust the thermostat to your desired temperature. Replace the front panel securely.

Common issues if the pilot won’t stay lit include a dirty thermocouple, a clogged pilot orifice, or a faulty gas control valve. If the pilot goes out immediately after releasing the knob or flame, reattempt lighting following the same steps, ensuring the thermocouple heats up. If the flame remains unlit after several attempts, stop and seek professional service.

Lighting A Water Heater With An Igniter (Intermittent- ignition Models)

Intermittent-ignition models use an electronic spark or hot-surface igniter. They typically do not require a lighter, but a lighter can still help in case the igniter fails. The steps below describe the ignition process with the igniter in place:

Set the gas control to Pilot or to On, depending on the model’s instructions. In some units, you must press and hold a control knob while triggering the igniter.
Press and hold the ignition button or control while observing the burner area.
If a spark is produced and the burner engages, release the control after the burner lights, and allow it to stabilize.
Set the thermostat to the desired temperature and replace any access panels.

If the electronic ignition does not ignite after multiple attempts, using a long lighter to manually ignite the burner through the access panel opening may be necessary. Only attempt this if you can clearly access the burner and ignition area without risk of contact with hot components.

Safety Considerations And Warnings

Always ensure adequate ventilation in the area to prevent carbon monoxide buildup.
Do not use a lighter if there is a strong gas odor; evacuate and contact the utility.
Keep flammable materials away from the heater and ignition area.
Do not attempt lighting if the unit is wet or damaged; contact a professional.
After lighting, test the area for gas leaks using a soap solution; bubbles indicate a leak that requires immediate repair.
Regular maintenance, including annual professional inspections, ensures safe operation and efficiency.

Maintenance And Troubleshooting

Regular maintenance can prevent many lighting issues. Clean the pilot assembly and burner openings to remove dust and debris that impede ignition. Replace a faulty thermocouple promptly, as a weak or damaged thermocouple can prevent the pilot from staying lit. For intermittent-ignition units, ensure the igniter electrode is clean and properly aligned with the burner.

If the pilot lights inconsistently or goes out after a short period, consider these checks:

Clean or replace clogged gas orifice orifice screens
Inspect gas supply and pressure to ensure it meets manufacturer specifications
Check the thermocouple for damage or misalignment
Inspect the flame sensor and wiring for continuity and corrosion

If uncertain about any procedure or the unit shows signs of wear or damage, contact a licensed plumber or a gas utility technician. Improper lighting or repairs can pose serious safety risks including fire or gas leaks.

When To Seek Professional Help

Lighting a water heater is a routine task for some homeowners, but certain conditions require professional service. If there is a persistent gas smell, a flickering or yellow flame (instead of a stable blue flame), or the unit fails to light after multiple attempts, arrange a service call. Gas lines, valves, and electronic ignition components are subject to wear and may require replacement parts or calibration by a qualified technician.

Energy Efficiency And Practical Tips

Efficient operation improves hot-water reliability and reduces energy usage. Keep the thermostat at a moderate setting (around 120°F or 49°C) to balance comfort and energy consumption. Regularly flush the tank to remove sediment, which can hinder heating efficiency. Consider upgrading to a modern intermittent-ignition model or a high-efficiency unit if the current system is aging or frequently requiring service.

Use the safe lighting methods described in this guide to minimize fuel waste and ensure quick burner ignition. Keeping a spare lighter on hand in a dry location can be convenient, but never place flammable items near the water heater.