Well pumps that are installed inside the well itself are submersible water well pumps. They come in two separate versions. The first kind turns on and off based on the pressure in the water storage tank. Pump manufacturers recommend their pumps run on what’s considered a 20 pound spread. This means there is a difference of 20 lbs of pressure between the setting that turns the pump on and the setting that turns the pump off. These standard type submersible pumps have been around for decades and have proven to be reliable with an average lifespan of 15-18 years.