Either above grade or below grade is safe. Technically the temperature of the earth will remain more consistent than above ground.
- This consistent temperature minimizes the expansion of the liquid propane in the tank.
- As a safety procedure, propane tanks are never filled past 85% whether above or below grade, allowing for the expansion of the liquid propane as the temperature rises.
The decision for above vs. below is based mostly on aesthetics. Try to envision how your property and sight lines would look if you were to remove the tank from view. This may help you decide on which direction to take. Keep in mind that the up front costs will increased when placing the tank below grade for excavation, foundation, and trenching of the line.
One important note, before making the decision to bury the tank you must know the location of your water table and its relationship to the depth of the tank. If you have a high water table the tank will need to be anchored by chains to two large concrete footings. If this is not done the tank will float up and out of the ground as the water table rises and the weight of the tank decreases. Again this adds to the up front cost.
Proceeding forward, consult your propane provider and request an estimate from them for placing the tank below grade.