Well Volume Calculator

When sampling a well, it is standard practice to pump out at least 3 times the volume of water that is in the well (called the “water column”). This is done to ensure that you get an accurate, representative sample of the groundwater and not any inadvertent contamination that may have resulted from the well being “stagnant” for a period of time. Since well bores are essentially cylinders, the volume calculation is a simple geometric equation () where r = well bore radius and h = the distance from the bottom of the well to the static water level. Our tool makes it fast and simple to calculate the volume of water (v) and multiply it by 3, thus saving time in the field calculating the purge volumes.

Select well diameter:

Enter well depth in feet:

Depth to water in feet:



Total volume of water in the column (gallons) =
Standard sampling purge volume (gallons) =

How to Add a Shortcut to this Calculator on your iPhone or iPad

  1. Open up this calculator on Safari.
  2. At the bottom of the screen you’ll see an icon depicting an arrow that looks like it’s trying to get away from a square. Tap this button.
  3. Tap “Add to Home Screen”.
  4. You’ll be asked to choose a name for the homescreen icon. May we suggest “Well Volume Calculator”?

Now you can click that icon to go directly to the Well Volume Calculator when you need it in the field!

How to Add a Shortcut to this Calculator on an Android Device

  1. Start by opening your the page in your browser. We recommend using the default Android Browser, or Google Chrome if possible.
  2. Hit the menu button, and add the page to your bookmarks. In Chrome, just tap on the star and follow the prompt.
  3. Open you bookmarks using the menu button, and find the new bookmark you’ve just added. Press down and hold on the bookmark until you see an action menu. Select Add to homescreen.

That’s all there is to it. The bookmark is pinned to the homescreen for quick access.

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