The submersible pump is the heart of a well water system. If the pump fails, or does not perform at 100 percent, the water pressure will suffer. The pumps primary job is to take the water in the well and push it up to the surface to the pressure tank.
Sediment can be a problem for any part of a well water system. Sediment can block the pump intake filter, clog pipes, clog valves, clog house filters, and clog the screen filters and valves on faucets. All of these issues have a negative affect on water pressure.
The pump is powered by electricity, so any problems with the pump's electrical system will have a negative affect on water pressure. The largest electrical problems with well water systems are bugs, lightning and cut power cables.
Well water systems have a pressure switch that regulates when the pump turns on. When the pressure falls below a certain value, the contacts of the switch will close, turning the pump on. When the pressure reaches the needed level, the contacts will open. Bugs can get into the pressure contact switch and prevent the contacts from closing. This can keep the pump from turning on.
The pressure tank helps maintain a set level of pressure in the system in between the times when the pump turns on and off. If the tank has leaks and cannot maintain pressure, then the system will not maintain a constant pressure.