Why Does My Well Pump Keep Turning On and Off?

If your well pump keeps turning on and off every few seconds, you're dealing with well pump short cycling, one of the most common (and most damaging) pump problems we see across Polk County.

Short cycling puts enormous stress on the pump motor. Every startup draws a surge of electrical current, and when that happens dozens of times an hour instead of a handful of times a day, motor windings burn out faster, pressure switches wear prematurely, and you end up with a pump failure that could have been avoided. Understanding what causes it is the first step toward fixing it before the damage gets expensive.

What Causes Well Pump Short Cycling?

The most common culprit is a failed or waterlogged pressure tank. Your pressure tank holds a cushion of air that absorbs the pressure swings between pump cycles. Inside most modern tanks is a rubber bladder or diaphragm that separates that air charge from the water. When the bladder fails, water fills the entire tank and there's no air cushion left. The pump pressurizes the system almost instantly, hits the cut-off pressure, shuts off, and then the pressure bleeds down just as fast, triggering the pump again. The whole cycle can happen in under ten seconds.

Other causes include:

• Low or lost air pre-charge in the pressure tank (the bladder is intact but the air pressure has dropped below spec)
• A leaking pressure switch or one with contacts set too close together
• A pressure tank that's too small for the household's demand
• Leaks in the system, a dripping faucet, a running toilet, or a leak in the supply line can cause the pressure to drop constantly, keeping the pump running in short bursts
• A partially clogged well screen or drop pipe restricting flow so the pump can't build pressure normally

How to Tell If Your Pressure Tank Is the Problem

The quickest field check: with the pump off and system pressure bled down, tap the side of the pressure tank from top to bottom with your knuckle. A healthy tank sounds hollow in the upper portion (that's the air charge) and solid toward the bottom (water). A waterlogged tank sounds solid all the way up. You can also check the Schrader valve on top of the tank, if water squirts out instead of air, the bladder has failed.

That said, do not attempt to adjust the pressure switch, recharge the tank, or pull any electrical components yourself. These systems operate at line voltage and at pressures that can cause serious injury. Call a licensed contractor.

What Happens If You Ignore Short Cycling?

Left alone, short cycling will shorten the life of your pump motor significantly. Submersible pumps are especially vulnerable because they're designed to run for longer, steady intervals, not rapid on-off bursts. Repeated thermal stress from frequent startups can burn out the motor windings. The pressure switch itself can arc and fail. In the worst cases, a burned submersible pump means pulling the entire drop pipe out of the well, a job that costs considerably more than replacing a pressure tank early.

How We Fix Short Cycling at Dunham Well Drilling

When we get a short-cycling call, we start with a pressure test and a visual inspection of the tank and switch before we pull anything apart. Most of the time the fix is a new pressure tank, and we stock Goulds, Sta-Rite, and Grundfos equipment, so we're not waiting on a parts order to get your water running normally again.

If the tank checks out, we look at the pressure switch settings, inspect for system leaks, and evaluate pump output. Our pump repair and installation team handles everything from residential jet pumps to submersible systems, and we have a full-line machine shop on-site for in-house rebuilds when a pump can be salvaged rather than replaced. That machine shop is something most well companies in Central Florida don't have, it means we can often rebuild a pump the same visit rather than sending it out and leaving you waiting.

We also carry new and used pump inventory (Goulds, Sta-Rite, Grundfos, and Schaefer), which matters when you need a replacement fast.

If you're in the Winter Haven area, our shop is right here at 1341 42nd Street NW, we know the local aquifer and the local water table, and that context matters when we're sizing a replacement tank or diagnosing why your system isn't holding pressure.

When Short Cycling Is a Well Emergency

If your well pump is short cycling and you're completely losing water pressure, no water at the tap, that crosses into emergency territory. A drinking water well that has stopped working is exactly the situation our 24/7 answering service is there for. Calls are returned within 48 hours, and our team prioritizes no-water situations.

Don't wait on a short-cycling pump. The longer it runs that way, the more likely you're replacing a motor instead of a tank.

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If your pump is clicking on and off more than it should, call Dunham Well Drilling at (863) 965-2881. We've been diagnosing and repairing well pump problems across Polk County since 1950, 76 years of working in this specific geology and climate. Our full-line machine shop is on-site, so pump rebuilds stay in-house. Reach out during business hours (Mon, Fri, 7:30 AM, 4:30 PM) or leave a message with our 24/7 answering service anytime.