At Reliant Energy Entex, we think that this a good rule whether it's a water heater being installed in a new home, or a replacement water heater being installed in an older home. Because fumes from flammable liquids tend to hug the floor, elevating the water heater can reduce the risk of fire or explosion, but it does not eliminate the risk. For total safety protection, you should store all flammables away from any appliances, gas or electric. Keep flammable products in tightly closed approved containers. Keep the containers far away from your appliances and out of the reach of children.
Water heaters have the main burner and pilot flame.
The pilot flame is on all the time and will ignite flammable vapors. These vapors are heavier than air and cannot be seen. Vapors may travel a long way on the floor and can be carried from other rooms to the pilot flame by air currents. This will reduce, but not eliminate, the risk of vapors being ignited by the main burner or pilot flame.