A gas water heater runs on a flame, a gas line and a vent, which is why a small problem can matter more than it would on an electric unit. Some warning signs are about comfort. Others are about safety.

United Plumbing provides gas water heater repair in Fort Myers, Cape Coral, North Fort Myers, Punta Gorda and across Southwest Florida, along with water heater repair and replacement for every fuel type. This guide covers the warning signs, the safety steps, and what a licensed plumber checks, so you know when to act and when to wait.

Stop And Call Right Away

Treat any of these as an emergency:

• The smell of gas: often described as a rotten egg odor near the heater or anywhere in the home.
• A carbon monoxide alarm sounding, or symptoms such as headache, dizziness or nausea that ease when you leave the building.
• Soot or scorch marks on the heater, the vent or the wall around it.
• Flames or a burning smell outside the burner compartment.

If you notice any of them, get everyone, including pets, out of the building. Do not use light switches, lighters or anything that could spark. Once you are outside, call your gas utility's emergency line or 911. Do not go back in until you have been told it is safe, and have a licensed plumber inspect the heater before it is used again. United Plumbing offers 24/7 emergency plumbing for the follow-up.

Warning Signs Your Gas Water Heater Needs Repair

• The pilot light will not stay lit: a common sign of a worn thermocouple or flame sensor, a draft or a venting problem.
• A yellow or orange flame: a healthy burner flame is mostly blue. A yellow, sooty or uneven flame suggests incomplete combustion and should be inspected promptly.
• Popping, rumbling or banging: usually sediment on the bottom of the tank. See why water heaters pop and rumble.
• Rusty or discolored hot water: can point to tank corrosion.
• Water around the base: a leak from a fitting, the relief valve or the tank itself.
• Little or no hot water: see 7 common water heater problems, and signs a water heater is about to fail.

On a gas appliance, carbon monoxide is the risk you cannot see or smell. A working CO alarm is not optional.

What Is Usually Wrong

What You Can Safely Do

• Check the temperature dial and make sure it has not been bumped or changed.
• Confirm the gas shutoff to the heater is open and other gas appliances are working.
• If there is a leak, shut off the cold water supply to the heater and call a plumber.
• Keep the area clear of paint, solvents, rags and other flammables.
• Test your carbon monoxide and smoke alarms and replace weak batteries.

Do not remove the burner cover, work on the gas line, tamper with the gas control valve or vent, or disable the relief valve. If the pilot keeps going out, do not keep relighting it. Call us.

What A Licensed Plumber Checks

• The gas supply and connections, including a leak check
• Burner and flame quality
• The thermocouple or flame sensor and the gas control valve
• Venting and draft, which matter for carbon monoxide safety
• The tank, the anode rod and sediment
• The temperature and pressure relief valve
• Water connections and any signs of leaks

From there you will get an upfront quote and an honest repair or replace recommendation. Our guides to water heater repair vs replacement and gas vs electric water heaters explain how that decision usually goes, and our water heater financing guide covers paying for a replacement. If you are comparing gas tankless, see tankless water heater repair and tankless installation.

Sources and Further Reading

• U.S. Consumer Product Safety Commission, gas water heater recalls and safety: cpsc.gov
• U.S. Department of Energy, water heating: energy.gov
• More guides from United: Fort Myers plumbing articles.

About the author: United Plumbing Inc has been the Fort Myers plumber for residential, commercial and new construction customers since 1980. Licensed technicians repair gas water heaters across Fort Myers, Cape Coral, North Fort Myers, Punta Gorda, Estero, Bonita Springs and the barrier islands. Florida License CFC 1433130. Head office: 3560 Teeside Lane, Fort Myers, FL 33916. Reviewed by United Plumbing's service management team. Last updated October 2026.