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Measure water level, depth and casing diameter

Static Water Level

Your static water level (often simply called "the water level") is the distance from ground level down to the water in your well. The meaning of "static" is the normal "resting" level of water --- i.e. when you are not pumping and haven't pumped recently. If you have pumped, then the water level, of course, is changing as the well fills back up to the static level ---- not the time to measure depth. (The speed at which your well refills - e.g. three gallons per minute - is called your "Recovery Rate".)

If you don't already know your water level, you can find it in the well driller's log, from when the well was initially drilled. Or you can measure it, as described here.

To determine your static water level yourself, you'll need

  • A THIN steel fishing weight
  • A THIN diameter bobber (i.e. float)
  • 200 feet of a lightweight fishing line or kite string.
How to Measure
  • Attach the weight to the end of the line or string. Attach the bobber one inch above the weight.
  • Remove the well cap and lower the weighted end with bobber into the well casing.
  • When the bobber reaches the water level, the line will go limp. You'll feel a slack in the line.
  • At the point where you feel the slack, mark the line at the top edge of the casing (you can tie a small knot in the line, use tape or a marker)
  • Pull the line back up from the casing.
  • Measure the length of the line from the bobber to the marked line. This is your static water level.

Well Depth

Your well depth is the distance from ground level to the solid rock at the very bottom of your well shaft.

If you previously measured the static water level, you can use the same line. Just remove the bobber from the line.

How to Measure
  • Lower until you feel slack.
  • Mark the line at the top edge of the casing.
  • Pull out and measure. This is your well depth - the distance to the bottom of the well shaft.

Well Casing Diameter

This calculation works for the most common schedule 40 metal well casing. If you have PVC, the outside diameter will be sufficient information.

  • Take a piece of string or soft (i.e. completely flexible) measuring tape. Wrap around your well casing and measure.

    VERY IMPORTANT: Make sure you measuring your WELL CASING - the metal shaft of your well - NOT the well cap on the top.
  • If string, put flat, with same degree of tension on it, and measure. This gives the circumference of your well casing.
  • Divide your well casing circumference by 3.14. The result is the outside diameter.
  • From this number, subtract 5/8". The result in your inside diameter - your well cap size.

Your result should be close to one of the standard sizes - 2, 4, 5, 6, 6.25 or 8 inches.


Pumps in stock. Trochu, Alberta
Phone: 403-442-4238