Low Water Pressure on a Well
Weak showers, a washing machine that takes forever to fill, pressure that drops when two taps run. On a well the cause is almost always one of five parts, and you can rule most of them out in an afternoon.
Likely causes
- Waterlogged pressure tank
- Pressure switch set too low or failing
- Clogged sediment filter or aerators
- Worn pump or pump running dry
- Scale or iron buildup in pipes
Tests to order
- Pressure gauge reading
- Tank air charge check
- Flow rate test
- Iron and hardness lab test
Treatment options
- Recharge or replace the pressure tank
- Adjust or replace the pressure switch
- Change filters
- Constant pressure pump controller
- Pump replacement
Watch the gauge first
Open a tap and watch the pressure gauge on the tank. Normal is a swing between about 40 and 60 psi with the pump cycling every minute or two. Pump cycling on and off every few seconds is a waterlogged tank. Pressure that never climbs past 30 is a switch setting or a tired pump. Pressure that starts fine and fades over ten minutes is a well that cannot keep up with the pump.
The five usual suspects, in order of cost
Aerators and any sediment filter come first: unscrew and check, five minutes and free. Next the pressure tank: shut off the pump, drain the tank, and check the air charge with a tire gauge at the top valve. It should read 2 psi below the cut-in setting. Water coming out of the air valve means the bladder failed and the tank needs replacing, $400 to $1,200. The pressure switch is a $30 part and can be adjusted up a few psi with a nut. If all that checks out, the pump itself is worn or the well is short on water, and that is a job for a licensed pump installer.
When the water is not the problem but the pipes are
Hard water and iron narrow galvanized pipe over decades. If a new pump did not help, the pipes may be the bottleneck. A flow test at the wellhead versus the far tap shows the loss.
Can I just turn the pressure up?
A few psi on the switch, yes, if the tank charge is adjusted to match. Pushing a 30/50 switch to 50/70 without checking the pump’s rating will shorten its life.
What is a constant pressure system?
A variable speed controller that runs the pump at whatever speed holds a set pressure, so the shower does not fade when the dishwasher starts. About $1,500 to $3,000 installed and worth it for larger homes.