Gas Water Heater Not Working? Common Causes and Fixes

When your gas water heater, a common household system that heats water using natural gas or propane. Also known as a gas-fired water heater, it's one of the most relied-on appliances in any home or business—until it stops working. No hot water means no showers, no clean dishes, and no way to keep a commercial kitchen running. If your gas water heater not working, it’s rarely a mystery—it’s usually one of five simple things gone wrong.

The most frequent culprit? The pilot light, a small, continuous flame that ignites the main burner in gas water heaters. If it’s out, the heater won’t turn on, even if the gas is flowing. It’s easy to relight—but if it keeps going out, the problem is deeper. A dirty or bent thermocouple, a safety sensor that tells the gas valve the pilot is lit. can fail over time, especially in dusty environments like restaurants or laundromats. Then there’s the gas valve, the control unit that regulates gas flow to the burner. If it’s faulty, you won’t get gas even if the pilot is burning. And don’t overlook simple stuff like a blocked vent or a tripped high-limit switch—both can shut down the heater without warning.

These aren’t just homeowner problems. In Birmingham, commercial kitchens, hotels, and care homes depend on reliable hot water. A gas water heater failure can shut down operations for hours—or worse, cost you a day’s revenue. That’s why knowing what to check first saves time and money. Most of the time, you don’t need a full replacement. A $30 thermocouple fix or a quick pilot light reset gets you back up and running. But if your unit is over 10 years old, or you’re seeing rust, strange smells, or loud popping noises, it’s not just broken—it’s a risk.

Below, you’ll find real-world guides from technicians who’ve fixed these exact problems in Birmingham businesses. From how to safely relight a pilot light to testing a gas valve without special tools, these posts give you the exact steps to take—before you call for help, or when you’re deciding if it’s time to replace it entirely.