FIND YOUR WELL'S DEPTH TO WATER
 

Find Your Well's Depth to Water

 

Read your manual for installation, operation, and safety information. This guide neither supplements nor replaces the Owner’s Manual.

Finding the depth to water in your well
Should you need to buy a water well pump, this information will be very useful when speaking with the store clerk or with a plumber. Listed here are three methods you can use to determine your well characteristics.

String and Weight Method
This is a simple method that can be done in a few minutes. Use of a thick cotton string permits easier detection of wet string.
Cost (0-5 scale): 1
Difficulty (0-5 scale): 1

Items Needed:
• Tape measure
• Ordinary string
• Fishing weight

Step One – Drop weight and string into well casing
CAUTION Take care putting anything into your well. Don’t use a weight that may get caught on pipes or edges in the well. Use a small fishing weight or a rounded object and tie it carefully.
Tie a small but heavy weight to the end of a piece of string (be sure there is enough string; some wells are very deep). Lower the weight into the well until you feel it touch the bottom.

Step Two – Mark the String
Take up the slack and use a Sharpie or other waterproof marker to mark the string at ground level.

Step Three – Measure
Pull the string and weight out of the well. Pay attention to the string as it is withdrawn and identify the location where the string becomes wet. Mark that point with the permanent marker. Stretch the string and measure from the bottom of the weight to the ground level mark. This is the depth of your well. The normal (or ‘static’) water level is the length of the dry portion of the string up to the ground level mark.
For relatively shallow wells (30' or less), a tape measure may be used directly, but a weight on a string assures that the line used to make the measurement is absolutely straight, thus more accurate.
If your pump pulls the static water level down when in operation, that loss of water level is called drawdown. The well drilling company will make that measurement.
Knowing well depth, static water level, drawdown and your expected water usage (gallons per minute), a pump can be specified that will best meet your water needs.

Bobber and Weight Method
Here is another method that uses slightly more sophisticated equipment.
Cost (0-5 scale): 1
Difficulty (0-5 scale): 1

Items Needed:
• Tape measure
• Fishing pole
• Fishing weight
• Fishing bobber

Step One – Measure Well Depth
CAUTION Take care putting anything into your well. Don’t use a weight that may get caught on pipes or edges in the well. Use a small fishing weight or a rounded object and tie it carefully.
If you do not have a well report from the well drilling company, you can use an ordinary fishing pole with a full reel of line. Attach a sinker to the line, drop it down to the bottom of the well, and take up the slack. Using a permanent marker, mark the line at ground level. Reel in the line and measure the distance between the mark and the sinker. This is the well depth.

Step Two – Measure Static Water Level
Remove the sinker and place a small bobber on the fish line. Drop the bobber down the well casing until it hits the water level. Take up the slack and mark the line. Reel in the bobber and measure from this new mark to the bobber. This is the static water level.
When your well was drilled, the well casing penetrated into a water aquifer. The aquifer is under pressure from all the earth surrounding it. Your well is like a straw and the water in the aquifer is pushed up the well until it equalizes with atmospheric pressure. That is the normal (or ‘static’) water level when the pump is not running.
If your pump pulls the static water level down when in operation, that loss of water level is called drawdown. The well drilling company will make that measurement.
Knowing well depth, static water level, drawdown and your expected water usage (gallons per minute), a pump can be specified that will best meet your water needs.

Popper Method
A “popper” can be used by a homeowner to measure the water level in a shallow large diameter well, or in an unused well that has no equipment installed.
Cost: From $2.48 to $7.47.
Difficulty: Simple

Items Needed:
• Tape measure
• 4” to 6” ½” pipe nipple
• ½” pipe cap
• Teflon tape (for threaded connections)
• String or fishing line

Step One – Assemble popper
CAUTION Take care putting anything into your well. Don’t use components that may get caught on pipes or edges in the well. Tie the assembly to the line very carefully.
Assemble the cap to the nipple, using Teflon tape for threaded connections. Attach a stout string or heavy gauge fishing line to the cap end of the assembly.

Step Two – Measure Static Water Level
Lower the assembly into the well casing. When the popper meets the water it will trap air inside the pipe. When the pipe is pulled out of the water a slight “popping” sound (thus the name!) is heard. The popping can be audible at a significant depth.
When the pop is heard, use a permanent marker to mark the line at ground level. Withdraw the line and popper. Measure the distance between the mark and the popper. This is the normal (or ‘static’) water depth.