A private well pump is a motor that runs when the pressure tank drops. You pay for minutes of a large motor, not a 24-hour trickle — unless a leak makes it cycle all day. A ½ to 1 horsepower pump is often 800–2,000 watts while it is up.
Short cycling (a waterlogged tank, a bad bladder, a leak) turns a few starts a day into dozens. That is hard on the pump and easy to see as a mysterious electric bump. The leak itself is also gallons on the water side if that water is metered; many wells are not metered the same way as city water.
Irrigation and filling a pool from the well are long pump runs. Those hours belong here.
Estimate minutes or hours the pump actually runs, and the motor watts. A leak habit on Water is the gallons story if you also track volume.
At 18.8¢ per kWh, 1,200 watts for 30 minutes a day is 0.6 kWh — about 0.11. If a leak makes it run 4 hours, that is about 0.90 that day, and the pump is doing the wrong job.
City vs well
City water users usually do not have this motor. Well users may pay 0 per gallon for the water itself and still pay this pump. Extra houses on the same well are extra runtime for whoever pays the electric.
Related
Usage estimate only — not a utility bill, load calc, or advice.