Water and Well Depth
"What is the difference between well depth, groundwater depth, or static water level?"
"Static water level", "depth to groundwater" or (simply) "water level" are synonymous phrases and define the depth or distance from ground level to the level of water within the 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. (The speed at which it refills - e.g. three gallons per minute - is called your "Recovery Rate".)
"Well depth" is defined as the full depth from ground level to the solid rock at the bottom of your well shaft.
This distinction is important because the static water level is the depth used to calculate the force required to pump water to the surface. This is true no matter the depth at which the pump cylinder operates, because the work of the pump starts when the water in the pipe starts to be lifted above the water in the well. How deep the intake is below the water surface is basically irrelevant to the force needed, because the sucker rods are so light. They add very little to the force needed.. We normally recommend, to accommodate natural groundwater level decline, that the Simple Pump pump cylinder be installed at a depth of 35-40 feet below the static water level.
"How do I determine the depth to groundwater or static water level?"
You can approximate the depth to groundwater from the well driller's drilling log when the well was initially drilled. If you don't have this information, you can contact a local well driller or practicing engineer to have the water depth confirmed by sounding or other measurement technique.
NOTE: If you want to determine your static water level yourself, you'll need: a small steel weight, a 1 1/4" to 1 1/2" diameter bobber, 200 feet of a lightweight fishing line or kite string.