How to reset a water heater, electric or gas
Resetting a water heater is often all it takes to get hot water back. Here's where the reset is on each type, how to do it safely, and what it means when it won't stay reset.
Updated October 21, 2026 · 5 min read · By the Heater Doctor team
Short answer
On an electric water heater, turn off the breaker, remove the upper access panel and press the red reset button near the thermostat until it clicks, then restore power. Gas water heaters don't have a reset button in the same way: you reset them by turning the gas control off, waiting, and relighting the pilot by the label's instructions. If it trips again, something is wrong and needs a repair.
What the reset button does
On an electric heater, the reset button is part of the high-limit safety switch. Lennox explains that it trips when the water gets dangerously hot and shuts off the heating elements. It's a safety device, not an on-off switch.
Reset an electric water heater
- Turn off the water heater's breaker. The wiring behind the panel is live otherwise.
- Remove the upper access panel with a screwdriver. Fold back any insulation and plastic guard.
- Press the red reset button firmly until you hear a click.
- Put the guard, insulation and panel back.
- Turn the breaker back on.
- Wait. Lennox suggests 30 to 60 minutes for the water to heat back up.
If the button doesn't click, it probably wasn't tripped, and the problem is elsewhere: a tripped breaker, a failed element or a bad thermostat.
Reset a gas water heater
Lennox notes that gas water heaters don't have a traditional reset button. Resetting one means relighting it. A. O. Smith's guide: turn the gas control knob off, wait 10 minutes for any gas to clear, set the knob to pilot and light it following the instructions on the heater's label, then turn the knob to on once the pilot stays lit.
Some gas heaters also have a thermal switch. On A. O. Smith models with a status light, the company says the thermal switch can trip if the heater isn't getting enough air, and you press the small button in its center to reset it. If it trips again, the air supply is the problem. On an older heater, A. O. Smith points to a clogged air filter or flame arrestor.
If it keeps tripping
A reset that won't hold means the safety switch is doing its job. Lennox warns that pressing it again and again without fixing the cause can make things worse. Common causes it lists:
- A shorted or damaged heating element
- A thermostat stuck on or reading wrong
- Loose, damaged or corroded wiring
- A failing or undersized breaker
- Water leaking onto electrical parts
Each of these needs a repair, and a thermostat that won't shut off can overheat the tank.
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Common questions
Where is the reset button on my water heater?
On an electric tank, behind the upper access panel, usually red and on or near the upper thermostat. Gas tanks generally don't have one.
How long after resetting will I have hot water?
Lennox suggests 30 to 60 minutes for an electric tank to heat back up.
Is it safe to keep pressing the reset button?
No. One reset is fine. If it trips again, the switch is protecting you from an overheating or electrical problem. Call for a repair.
Sources
- Lennox, How to Reset Your Water Heater
- A. O. Smith, How to Relight a Water Heater's Pilot Light
- A. O. Smith at Lowe's, Reset the Thermal Switch
General information only. Gas, electrical and pressure work can be dangerous; when in doubt, call a licensed professional.
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