Skip to content

Calculator · Below ground

How much water does a round sump pit hold?

Enter the pit's diameter and depth to get its volume in US gallons, with a diagram alongside the result.

Empty-cylinder volume. It doesn't subtract a pump or fittings and isn't pump sizing.

DRAINAGE CALCULATOR

Sump pit volume

How much water occupies a cylindrical basin at a given depth?

SEE THE VOLUME

The water held inside a cylindrical basin
The water held inside a cylindrical basin. 24-inch inside diameter, 24-inch water depth.24 in inside24 inWATERDEPTH
  • 24-inch inside diameter
  • 24-inch water depth

Illustration not drawn to scale. Use the inside diameter and the water depth. The drawing does not establish the basin height.

Showing the starting values. Change the inputs and calculate to update the picture.

ESTIMATED VOLUME

Enter values to calculate.

Calculated locally in your browser. Your measurements are not sent.

The calculation.

Gallons = π × (inside diameter inches ÷ 24)² × (water depth inches ÷ 12) × 7.48051948.

A worked example.

A 24-inch inside diameter and 24-inch water depth gives about 47.0 gallons.

What the number means.

Assumes a straight-sided cylinder and does not subtract the volume occupied by a pump or other equipment. Water depth is not necessarily basin height. This does not size a pump or predict cycling, groundwater inflow or storm performance.

Want FAS to look at your property?

Tell FAS what you are noticing. A short chooser suggests a first step and shows its fee before you request anything.

All tools