How Well Pressure Is Supposed to Work
A well system has three main parts working together: the pump down in the well, the pressure tank, and the pressure switch. The switch tells the pump when to turn on and off. The tank holds a cushion of air that pushes water to your taps between pump cycles.
Switches are set to a range, like 30-50, 40-60 or 60-80. The most common is 40-60. That means the pump turns on at 40 psi and off at 60 psi. When any part of that team is out of balance, low water pressure on a well is usually the first thing you notice.
Is the Pressure Low Everywhere or Just One Spot?
Start here. It saves time and money.
- One faucet or shower is weak. Check the aerator or showerhead for mineral buildup. This is often a fixture problem, not a well problem.
- Hot water only is weak. Look at the water heater and its lines.
- The whole house is weak. Now the well system is the suspect. Keep reading.
Common Causes of Low Water Pressure on a Well
The pressure tank is out of balance
The tank’s air charge should sit about 2 psi under the switch low setting, so around 38 on a 40-60 switch. When the air charge is low, the tank holds less water and the pump short cycles. You can check it yourself with a tire gauge. Our guide to checking pressure tank pressure shows the steps. A tank that keeps losing air may need replacing, which is covered on our pressure tank replacement page. We install Well-X-Trol tanks.
A clogged sediment filter
If you have a whole-house filter, a clogged cartridge can choke your pressure. Iron and sediment, common in parts of Prince William, can clog them faster than you might expect. Our water treatment page covers filtration options.
The pressure switch
Switch contacts wear out and settings can drift. This is a job for a technician, since the switch carries live power. Please do not open the cover.
A leak in the water line
A leak between the well and the house means some of your water never reaches the taps. Watch for soggy ground or water pooling near the well, or hissing at the casing. That can mean a leak at the pitless adapter or inside the well. Read water pooling near the well, and see our water line repair page.
A worn pump
Pumps lose strength as they age. A worn pump may run longer and still struggle to reach the shutoff pressure. If you are seeing other warning signs too, read 7 signs your well pump is failing.
The well cannot keep up
Some wells simply produce water slowly, especially in dry stretches. If pressure drops during heavy use and recovers after a rest, the well may be drawing down. A flow test can tell you. Spreading out laundry, showers and lawn watering can help in the meantime.
Pressure that vanished after a power outage
Some pressure switches have a low-pressure cutoff with an outside lever. After a power outage, the switch can drop out and will not restart on its own until it is reset. If your pressure went to nothing right after the lights flickered, check the well breaker, then give us a call and we will handle the reset. If you have no water at all, call 703-776-0996.
A Safe Home Checklist
- Check aerators and showerheads for buildup.
- Look at any whole-house filter and change a dirty cartridge.
- Walk to the well and look for wet ground or listen for hissing.
- With the well breaker OFF and cold water run until it stops, check the tank air with a tire gauge.
- Turn the breaker back on and watch the pressure gauge as the pump fills the tank.
Anything beyond that is ours to handle. You should never need to touch wiring to figure this out.
Constant Pressure Systems
If you are tired of pressure that rises and falls, a constant pressure system is worth a conversation. It adjusts the pump speed to keep pressure steady. We install Grundfos, Gould and Myers systems, and our well pump repair and replacement page has more.
Help Around Prince William
Pressure problems are common calls for us in Gainesville, and on the outer edges of Centreville near Clifton, where homes on private wells sit next to public water areas. Our diagnosis is free within reason. Call 703-791-3981 and tell us what you are seeing.