Homeowners who rely on a well as their source of drinking water usually suspect the well pump first if a water supply problem develops. However, the pump itself is just one of several components required to deliver water from a well. A problem with low water pressure can be caused by a separate aboveground switch instead of the pump itself.
Well pump systems are so reliable that you might go for years without any hint of a problem. Because of that reliability, you are likely to notice any unusual drop in water pressure immediately. Although well pumps can eventually require maintenance, the separate pressure control switch is much easier to replace than a pump.
Normal range of water pressure
You have probably noticed that your water pressure increases or decreases slightly when water is used. That slight change in pressure is normal. The pressurized water tank delivers a certain amount of water before the pump has to be switched on to refill the tank. If the water pressure drops to a level that is outside of the normal range, however, there is a problem somewhere in the system.
Water pressure is measured in pounds of pressure per square inch (psi). There is normally about a 20 psi differential between the lowest pressure and the highest pressure in a well water system. The aboveground switch is responsible for turning the pump on and off at the designated pressure levels. There should also be a readable pressure gauge located near the switch.
Pressure gauge readings
If the gauge is working properly, the pressure reading should change quickly in response to increases or decreases in system pressure. To observe the actions of the gauge, open up a faucet or a water outlet. The lowest pressure reading should typically reach either 20 psi or 30 psi, depending on your switch settings. At that point, the gauge should begin to move upward and stop at either 40 psi or 50 psi.
The 20 psi differential in pressure is essential to prolong the life of the pump. When the pump is not running, the compressed air in the pressure tank pushes water out of the tank as water is needed. As a result, the pump runs fewer cycles and undergoes less wear. If your system is reaching the correct high-pressure level, the well pump is probably working correctly.
If your water pressure drops below 20 psi, the switch may be failing to turn the pump on. If your highest water pressure is normally 50 psi, a low-pressure reading of less than 30 psi may also be due to a defective switch. Contact a plumber for further assistance in well pump repairs.