DIY Inspection – Gas Water Heater Problems & Solution Tips


When servicing a gas water heater, the very first step is to shut off the gas by turning the shut off valve on the in-line gas pipe. When it is shut off the valve handle will be perpendicular to the in-line pipe. After shutting the gas off, wait for 5 to 10 minutes for the gas fumes around and inside of the water heater to clear out. Natural gas and propane gas have a fowl and peculiar odor. The annoying odor is added to the gas purposely to make us aware of its presence and to warn us of a gas leak if the odor is present.


Remove the outer access panel cover and the inner access panel cover. The inner access panel cover is a galvanized plate that is normally held in place with brackets not with mechanical fasteners. The panel covers stop air drafts from extinguishing the pilot light. The panel covers should always be in place.

After the covers are removed, inspect the pilot light orifice and the gas burner to make sure there is no dirt or debris clogging them (such as rusted metal fragments). If the pilot light orifice and the round gas burner are clean, the pilot light may not be staying lit because of the thermocouple. The thermocouple is a safety device that senses heat from the pilot light. If the thermocouple does not sense heat it will not allow gas to be emitted to the pilot light. The thermocouple is a thin copper wire that can be seen connected to the temperature control, on the lower outside of the water heater, (where the thermostat is located). From the temperature control it runs into the flame of the pilot light. The thermocouple is inexpensive and easy to replace.


The occurrence of a “rotten egg” odor or black water in the hot water lines is caused by a reaction between the anode rod and the water. The water may be contaminated with bacteria. The anode rod will need to be replaced. This task should be performed by a plumber. Most anode rods are made of magnesium. Ask the plumber to install an aluminum rod. It will last much longer, and more than likely it will last the life of the water heater.

If the house has been vacant for a long time and water was left in the water heater tank, The rotten egg odor may be caused by stagnate water, concentrations of sulfate and/or microorganisms. If this scenario exists, first shut off the incoming water, and drain the old water and refill.

Home Inspectors occasionally find this odor problem in vacant homes when the water heater is left energized and no new chlorinated water flows into the tank. After the chlorine dissipates, bacteria thrive in the hot water. This is found with homes on well water more often. (No chlorination added).


The temperature & relief valve is more often referred to as the T&P valve. Every water heater, gas or electric, should have a T&P valve. It is a safety device. The T&P Valve is connected to the discharge pipe. The purpose of the valve is to relieve excessive pressure from inside of the tank. The T&P valve is usually set to open or relieve the pressure if it exceeds 150 PSI or if the temperature exceeds 210 degrees. When water is heated it expands, which increases the pressure. The temperature is controlled by the thermostat. If the thermostat becomes defective, and the temperature overheats, the pressure could cause the water heater to explode, which is catastrophic.

If water is dripping from the T&P valve, check the thermostat to see if the temperature has been set too high. It should be set at 120 to 150 degrees. Also, test the temperature of the water at a faucet by running the water into a coffee cup and place a thermometer in the coffee cup. Compare the waters temperature to the thermostat setting.

As a safety measure: If the water comes out of the faucet steaming hot, leave the house immediately. It is a good indication the T&P valve is defective, and the water heater could explode. The explosion of a water heater has been compared to a dynamite explosion. Call a plumber if these conditions are observed..

Maintenance tips will recommend the T&P valve should be tested once a year. A discharged pipe should always be attached to the T&P valve that leads to within 3 inches from the floor to prevent someone from getting sprayed by the hot water. To test the valve, lift the lever on the valve to allow water to come out. If water does not come out, you may have a defective T&P valve and it will need to be replaced. If the valve drips after testing it, the valve should be replaced.


This noise can be heard on both Electric and Gas water Heaters. The noise is normally caused by the build up of sediment from hard water in the bottom of gas water heater tanks. The sediment heats up and explodes in the tank. It can happen on any age of water heater from around three years old on up, most of the time it will be more noticeable on older tanks.

Electric Water Heaters have the same type of build up around the heating elements. Replacement of the heating elements would be suggested.

Some of the sediment will be removed by draining the water heater. Some of the sediment is too large to leave the drain pipe of the water heater and will remain inside of the tank. This draining may become part of routine maintenance until the tank is replaced. This phenomenon happened to my tank, and knowing the issue at hand, I wasn’t too concerned; however, after hearing it all of the time, I finally replaced the water heater. (Most people will).

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