Well Pump Cycling Constantly? How to Tell a Buried Line Leak From a Pump Problem

What cycling tells you

A well pump turns on when the pressure in the system drops to a set point, typically 40 psi, and turns off when it reaches the high point, typically 60 psi. With nothing running, pressure should hold and the pump should stay off for hours. If it turns on with nothing running, pressure is being lost somewhere, and the question is where.

The rhythm of the cycling is a clue. Rapid short-cycling, on for a few seconds and off for a few seconds, is usually a waterlogged pressure tank that has lost its air charge. Slow, steady cycling, on for a minute every ten or twenty minutes with nothing running, is usually a leak: in the buried line, in the house, or back down the well through a failed check valve.

Isolate and watch

The buried line can be isolated at two points: the shutoff after the pressure tank, and the shutoff where the line enters the house. Close the house shutoff first. If the pump keeps cycling, the loss is in the buried line or at the pump and tank. Now close the valve after the pressure tank, isolating the buried line entirely. If the pump keeps cycling with the buried line isolated, the loss is at the pump, the check valve or the tank, and the buried line is innocent. If the cycling stops, the buried line is where the water is going.

A pressure gauge at the tank makes this easier to watch than listening for the pump. Isolate the line, note the pressure, and watch for a drop over ten or fifteen minutes.

The check valve

A failed check valve lets water drain back down the well when the pump stops, which drops pressure and starts the pump again. It looks like a leak and it isn't one. If the pump cycles with both the buried line and the house isolated, the check valve is the first suspect, and that's a well pump company's job rather than ours.

If it's the buried line

Well lines in Olalla, Seabeck, Lofall, Hansville and much of Bainbridge run hundreds of feet from the well house to the home, through hardpan and boulders, and most were installed in the 1970s and 80s in polyethylene that is now brittle. A break on that line is found the same way as on a utility line: trace the route, correlate across the run, pinpoint with the ground microphone, and dig once. Where the line has failed before, a continuous HDPE replacement is often the better long-term money than a third spot repair.