When you have no hot water, the cause is often simple: a gas water heater's pilot light has gone out, or an electric heater's high-limit reset button has tripped. Both are safe for a homeowner to address if you follow the steps carefully. The most important rule with a gas unit: if you smell gas, stop, leave, and call the gas company — do not try to relight it. For everything else, this guide walks you through relighting a gas pilot or resetting an electric element before you call a plumber.
What you'll need
- A flashlight
- A long-reach lighter (for older pilots)
- Work gloves
- The label/manual on the tank (for the exact lighting sequence)
Recommended parts & supplies
- Water heater thermocouple — if the pilot lights but will not stay lit
- Water heater element and thermostat — for an electric heater that keeps tripping its reset
- Water heater igniter — for a spark igniter that no longer clicks
- Combustion chamber flame arrestor screen — a blocked screen can starve the pilot
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Step by step
- 1
Rule out a gas smell first
Before anything, sniff around the base of a gas water heater. If you smell gas (a rotten-egg odor), do not touch any switches or flames. Leave the house and call your gas utility or 911 from outside. Only continue if there is no gas smell.
- 2
For a gas heater, find the control and pilot
At the bottom of a gas tank is a gas control valve with a knob marked ON, OFF, and PILOT, plus a status light on newer units. Read the lighting instructions printed right on the label — sequences vary by brand. Turn the knob to OFF and wait five minutes for any gas to clear before you try to relight.
- 3
Relight the gas pilot
Turn the knob to PILOT and press it down to release gas to the pilot. On a newer sealed unit, click the built-in igniter button repeatedly until the pilot catches. On an older open unit, hold a long lighter to the pilot. Keep the knob pressed for 30–60 seconds after it lights so the thermocouple heats up, then release and turn the knob to ON.
- 4
If the pilot will not stay lit
If the pilot lights but goes out the moment you release the knob, the thermocouple (the thin sensor next to the pilot flame) is likely failing or dirty. Holding the knob longer sometimes helps temporarily, but a thermocouple that keeps dropping the flame needs replacing — an inexpensive part but fiddly to fit.
- 5
For an electric heater, hit the reset button
Electric heaters have no pilot. First check the breaker. Then remove the upper access panel on the side of the tank, fold back the insulation, and press the red reset button on the high-limit thermostat — it clicks when it resets. Turn the power off at the breaker before touching anything inside the panel.
- 6
Wait and test the hot water
After relighting or resetting, give the tank 30–45 minutes to heat a full load of water, then run a hot tap. If you have hot water, you are done. If a gas pilot keeps going out or an electric reset trips again, stop resetting it and call a pro — repeated tripping signals a failing part.
When to call a pro
Call a licensed plumber if you smell gas at any point (after leaving and calling the gas company first), if the pilot will not stay lit after you have held the knob and cleaned around it, or if an electric reset button trips again after you press it — that points to a failed element or thermostat drawing too much current. Also call for any water leaking from the tank itself (a leaking tank cannot be repaired and needs replacement), rusty or smelly hot water, or popping and rumbling from heavy Houston sediment. Gas valve and element work involves gas and 240-volt power, so leave those to a pro unless you are qualified.
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No Hot Water — FAQ
Why does my water heater pilot light keep going out?
Where is the reset button on an electric water heater?
Is it safe to relight my own gas water heater?
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