How power reaches a well pump

On most rural Sebastopol parcels, the pump is fed from a breaker in the house panel or a subpanel. The circuit runs out to a disconnect near the well or pressure tank, then through a pressure switch that turns the pump on and off as tank pressure rises and falls. Many systems also have a control box, or a newer variable-speed controller, mounted near the tank.

The pump itself might sit down in the well or up at the surface, depending on the setup. Either way, a good share of the wiring lives outside, often on a post or a wellhouse wall, exposed to wet winters, summer sun, and the occasional gopher.

That chain matters because a failure anywhere along it looks identical from the kitchen: no water, or pressure that sputters and dies. The pump company knows the pump, the tank and the switch. We know the circuit that feeds them. Calling the right one first saves you a wasted visit and a second wait.

Older farmhouses add a twist. Over the years, owners have a way of tapping into the well circuit because it was the closest power to wherever they needed it: a barn light, a gate opener, a stock tank heater. Each of those shares the pump’s breaker, and each is one more place for a fault to start. Some of them were never meant to sit on that circuit at all, and a pump starting up on a shared line pulls voltage away from everything else attached to it.

Safe checks before you call anyone

Start at the house panel. Find the breaker marked for the well or pump, keeping in mind that labels on older farmhouse panels are often wrong. If it has tripped, reset it once. If it trips again right away, leave it off and call us. A pump breaker that trips instantly is reporting a short or a failing motor, and more resets only add damage.

If the breaker is on, check the disconnect near the tank or the well. Someone may have switched it off for work and forgotten, or an old switch may have failed.

Then stand by the pressure tank and watch the gauge while someone opens a tap. If pressure drops and you hear the switch click but the pump never starts, that points one way. If you hear nothing at all as the gauge falls, that points another.

Do not open the pressure switch cover or a control box. Both carry line voltage even while the pump is idle, and the water nearby makes them unforgiving. Looking and listening is where the homeowner part ends.

Pressure switch trouble or an electrical fault

Some symptoms lean toward the pump side. Pressure that cycles rapidly on and off usually means a waterlogged tank or a failed bladder. A pump that runs but builds no pressure suggests a problem with the pump, the piping or the well. A switch with pitted contacts may chatter or stick, and replacing it is routine work for a pump company.

Other symptoms lean electrical. A breaker that trips. A disconnect that feels warm or looks discolored. Lights that dim hard every time the pump starts, which can mean voltage drop on a long, undersized run out to the well. Corrosion or a burned smell at a junction box. A pump that hums but will not spin sometimes has a failing capacitor in the control box, which either trade might handle depending on the system.

Measuring voltage at the switch while the pump tries to start separates most of these. If full voltage arrives and the pump still will not run, the trouble is downstream. If voltage sags or never shows up, the circuit is the problem. That measurement is how we decide, instead of a hunch.

What a PSPS shutoff does to your water

When the utility cuts power during high fire-risk weather, a well pump stops along with everything else in the house. The pressure tank holds a small reserve, and once that is used up, the taps go quiet.

For households on rural parcels, that makes the well the first circuit on any backup plan. A generator with a transfer switch or an interlock, or a battery system with the pump on its backed-up loads, keeps water running through the outage.

There are details to get right. Pumps draw a surge when they start, so the backup source has to handle that starting load and the running load both. Some older pumps are hard starters. The well circuit may need to move into a backup loads panel. And no portable generator should ever feed a house through a dryer outlet or a backfed breaker, because it can energize the utility’s lines and injure the crews working on them.

If your well went quiet during the last shutoff, now is a good time to plan, and the panel is usually part of that conversation.

Who to call first

Call the pump company when power is clearly arriving: breaker on, disconnect on, the pump humming or running, and the complaint is pressure, flow, cycling or water quality.

Call an electrician when the breaker trips, the disconnect or switch looks burned, lights dim sharply at pump start, outdoor wiring has been damaged, or there is no power at the switch at all. Call us as well when you are adding backup power, replacing an old panel, or running a new feed out to a wellhouse.

When it is unclear, either one is a reasonable first call, and the two trades often end up working on the same well. We are glad to test the circuit and hand the pump company a clear answer if the fault turns out to be theirs. Testing before replacing keeps you from buying a new pump when a corroded connection was the whole story.

Old well wiring is also one of the things we look at during an electrical safety inspection of a farmhouse you are thinking of buying.

Looking after the wiring out at the well

Most well circuits fail slowly, and a walk out to the tank once a year catches a lot of it. Look at the disconnect and any junction boxes for covers that no longer close, rust streaks, or holes where a wire enters. Check that the conduit is still strapped to its post or wall and has not pulled apart at a fitting. Rodents like wellhouses, so look low for chewed insulation.

Keep brush and ivy off the equipment, since damp growth holds water against the boxes all winter. Make sure the pump breaker is labeled correctly, and write down anything else that shares its circuit. If the lights still dim hard at every pump start, bring it up now instead of on the day the water stops.

When something does fail, a note of when the water stopped, whether a storm or shutoff came first, and what you heard at the tank shortens the visit. Past work is in the gallery, and our Sebastopol page covers the rest of what we do around town. The person who answers (707) 684-0024 is the person who shows up, the contact page works too, and you will hear what it’ll cost once we know where the fault is.