When dealing with a water heater in your home, you should, first of all, locate the shut-off valves for the gas supply and cold water supply to the heater.
Regular maintenance is very important for the home owner to keep in mind.
This would consist of flushing the heater for the hose faucet provided near the bottom of the heater.
Connect a hose to the hose faucet and run it to the nearest drain.
Open the faucet and be sure to leave the cold water supply in the open position.
Run for 4 to 5 minutes.
This should be done every 3 to 4 months on a regular basis.
Should you be experiencing little or no hot water upon opening your faucet, the problem could be lying with the dip tube in the cold water supply to the heater. If so , this would have to be replaced.
If you experience a bad odor coming from your hot water (rotten eggs,) your anode rod may have to be replaced. Do not plug this opening off as it would void your warranty.
If you notice that your relief valve is dripping, try flushing it by pulling the lever on the relief valve. If this does not work, then replace it. Be sure to replace it with a relief valve with the proper pressure and temperature rating.
The temperature setting on your water heater should be at about 130 degrees, if you have anti-scald valves on your bath tub faucets and shower valves. If not, it should be set at 110 degrees.
If you have a power vent or a more complicated water heater, this should be repaired by a certified plumber.
Lastly, do not store any flammable materials near your water heater.