Same as with an electric water heater, you should first check the cold water inlet and hot water outlet pipes and connections to make sure they are not loose. A faulty or loose temperature and pressure relief valve or inlet valve may also be the cause of leak.
When you see water that appears to be leaking from the bottom of a gas water heater, it could be because of condensation (try turning up the thermostat), a leaking or loose drain valve, or the T&P valve draining some water through the overflow pipe due to tank overpressurization.
If the leak is from the water heater tank due to corrosion, replacement of the water heater is necessary. See Water Heater Leaking from the Bottom for additional information.
The very first thing to check is if you have gas flow and that your pilot light is on. If yes, the issue may be with the thermocouple which is not correctly sensing that the pilot light is on and in turn does not ignite the gas. The thermocouple may need to be replaced (or simply cleaned).
If you have a newer style water heater with electronic ignition, check your breaker box to see if the circuit breaker is tripped. See here for more info.
Some reasons for not having enough hot water or running out of hot water too soon include not having the thermostat set at a high enough temperature (especially in the winter months), a faulty thermostat, or a broken or damaged dip tube which allows the incoming cold water to mix with the hot water at the top.
Sometimes not enough hot water is simply because you have a water heater tank that’s too small for your needs. Even though you may have a 40 gallon tank, only about 28-30 gallons of it may be usable hot water at a time. Upgrading to a larger water heater or a tankless model may be in your future.
Most likely, you have the thermostat set too high. This is most common when transitioning to the warmer Spring and Summer months and forgetting to set back the temperature after raising it to account for the colder Winter temps. Less likely is a faulty thermostat that needs replacement.
If it feels like your gas water heater recovers too slowly, the thermostat may be set too low, the burner orifice may be too dirty or clogged and requires cleaning, the gas pressure may be too low, or the vent flue may be too dirty and also require cleaning.
For many, it’s simply a matter of having too small of a water heater tank for their family’s needs and it’s never given a chance to fully recover.
If you have an older home, there’s a good chance you have the smaller 1/2-inch diameter galvanized piping throughout your home. This greatly reduces the amount of hot water than can flow through your home’s plumbing.
Unfortunately, the only way to get noticeably higher hot water pressure is to switch out to the newer 3/4-inch piping that’s used in today’s homes. Definitely not a small task.
You may be able to slightly increase water pressure by cleaning out sink aerators or shower heads which tend to get clogged over time. Also, make sure your water inlet valve is fully open and not partially closed.
When you know exactly how to light a pilot light on a water heater yet it won’t light, there are a few possibilities as to why. Either the pilot light orifice or tube is clogged or needs replacement, the thermocouple is loose or faulty, there is air in the gas line, or the gas valve is defective.
Just as annoying as a pilot light that won’t light, is a pilot light that frequently goes out. Often, thermocouple replacement is necessary but there are other reasons if your pilot light keeps going out. Other possibilities include a bad gas valve or partially clogged vent which can cause downdrafts that blow out the pilot light.
A burner that at times goes out or produces an unusual, higher or lower than usual flame or even a whistling sound, is most often due to dirty or clogged burner orifices. As with the pilot light, a faulty thermocouple or dirty vent may also be the cause of the problem.
Same as an electric water heater, hissing, popping, knocking, or banging noises can sometimes come up. On gas models, this is typically due to sediment build up in bottom of the tank, expanding/contracting piping which rubs against wood framing within the walls, or dirty/clogged parts which gas flows through.
Once again, corrosion of the anode rod or the inside of the water tank itself is usually to blame. While replacing the anode rod isn’t complicated or expensive, the bigger problem lies if the tank shows signs of corrosion. It’s then only a matter of time before a leak develops and a new water heater will be needed.
Likely due to bacteria build up inside the tank. Simply turning up the thermostat to about 140 degrees should kill off the bacteria but a full clean-out of the tank with chlorine bleach may be necessary. If the smell comes back, the anode rod is likely at its end of life and will need replacing.