If your home has a relatively shallow well, you likely have an above-ground jet pump that pulls water from your well and into your home. Deeper wells require submersible pumps since jet pumps can't create sufficient pressure to move water from a much deeper source. Fortunately, it's often easier to diagnose problems with jet pumps since they're in your home instead of a hundred feet below ground.
Of course, an easily accessible pump may seem like cold comfort if yours isn't working correctly. One common issue with well pumps is that they shut down too quickly, either cutting off your water supply or noticeably reducing water pressure throughout your home. There are numerous reasons why this can happen, although these are three of the most common.
1. Loss of Prime
Unlike submersible pumps, which are self-priming due to sitting below the water level in your well, jet pumps require priming and can potentially lose their prime. Depending on the configuration of your jet pump, you will have either one or two pipes entering your well. Whatever the case, it's necessary for water to fill the suction line for the pump to have sufficient priming.
If your pump suddenly stops working or you can hear cavitating (air bubbles) from the pump housing, there's a good chance your pump is losing prime. Repriming your pump by adding water may temporarily resolve the issue, but it's likely to return. You will need a plumber with residential well experience to help you determine why your pump lost its prime in the first place.
2. Clogged Pressure Tubes
Water with high mineral content (typically known as "hard" water) can cause numerous plumbing problems. Unfortunately, your jet pump is just as susceptible to issues from hard water as any other plumbing fixture or appliance in your house. The pressure tube is one of the components on your pump that's most likely to experience issues from scaling.
The pressure tube is a simple tube that runs to your pump's pressure switch. The switch uses the tube to measure the pressure in your system, allowing it to determine when the pump should run. Hard water scaling can "clog" this tube, causing inaccurate readings and forcing the pump to shut off before there's enough pressure in the system.
3. Faulty Pressure Switches
A faulty pressure switch is another common issue that can cause your pump to shut off too soon. Pump pressure switches typically include a high and low cutoff. The pump turns on when your home's water pressure falls below the low cutoff. Once the pump turns on, it will continue running until the pressure reaches the high cutoff, at which point the switch cuts power to the pump.
Pressure switches can fail for numerous reasons, from sticky or rusted mechanical contacts to wiring issues. Since your pressure switch will operate at line voltage and can be a serious electrical hazard, it's important to allow an experienced plumber to diagnose and repair this issue.
To schedule repair or maintenance services, contact a well pump company in your area.