Well Volume

Understanding Well Water Volume

Whether you own a residential water well, manage an agricultural system, or work in environmental monitoring, knowing the volume of standing water in a well is essential. The Well Water Volume Calculator helps you quickly compute the quantity of water inside any cylindrical well casing based on its depth and diameter dimensions.

Calculating the water column is particularly critical for well purging (the process of removing stagnant water before collecting groundwater samples) or assessing well recovery rates and overall aquifer capacity.

The Mathematical Formula for Well Volume

A standard water well is geometrically a cylinder. Therefore, the volume of water is determined by the cylinder volume formula:

Where:

• $V$ represents the standing water volume.
• $r$ is the radius of the well casing (which is half of the diameter, $r = \frac{d}{2}$).
• $h$ is the height of the standing water column, calculated as the total well depth ($D$) minus the depth to the water table ($W$):

Once the volume is calculated in cubic feet or cubic meters, it is converted to standard liquid measurements like US Gallons or Liters to provide actionable data for pumps, testing, or chemical treatment.

Common Casing Diameters and Volume Factors

Residential water wells typically use standard casing sizes. Here is a quick reference for the volume of water per foot of depth for common diameters:

• 2-inch casing: Approximately 0.16 gallons per foot (0.61 L/m)
• 4-inch casing: Approximately 0.65 gallons per foot (2.43 L/m)
• 6-inch casing: Approximately 1.47 gallons per foot (5.47 L/m)
• 8-inch casing: Approximately 2.61 gallons per foot (9.72 L/m)