I have a shallow water well that is 30 feet in depth.

I have 8 feet of water in the well.

The water well is a 30 inch in diameter.

My question : How many gallons of water is in my tank?

Thank you very much.


Hi Martha,

I know that there are 231 cubic inches in an American gallon so I will change all your measurements to inches. There are 12 inches in a foot so the depth of water in the well is

12 x 8 = 96 inches.

The volume of a circular cylinder is pi r2 h where r is the radius and h is the height. Thus the volume of water in your well is

pi r2 h = pi x 152 x 96 = 67858 cubic inches.

There are 231 cubic inches in a gallon so this is

 67858/231  = 294 gallons.