Floors are rarely perfectly level. Because of this, an important part of a hot water heater's installation is leveling it by using shims. A level water heater is important for the proper functioning of the water heater. Wood or plastic shims can be purchased from any home improvement store. Level your water heater after setting it in place, before doing any installation. Remember that water heaters need at least six inches of space around them for ventilation.
Things You'll Need
Place a carpenter's level on the side as well as on the top of the water heater to determine which side of the water heater needs to come up.
Tilt the water heater up just enough to place a shim under the leg on the side of the water heater that needs to come up. Keep adjusting the shim and checking the level until you have a water heater that is horizontally and vertically straight. Place more than one shim under the water heater if necessary. Do not push on the middle of the metal casing when tilting the water heater as this can dent the casing or cause damage to the interior lining.
Set the water heater back down carefully. Do not drop or jolt the water heater as this can damage its fragile interior elements. Tilt by lifting from the bottom or by pushing at the top edge.
Use extra shims under any other raised legs to buffer rocking.
Have someone help you. One person can tilt while the other person places the shim.