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
How to Measure