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Well Pump Short Cycling? Causes and Fixes

If your well pump kicks on and off rapidly, it's short cycling — usually a waterlogged pressure tank. Here's how to diagnose and fix it before the pump burns out.

3 min read

If your well pump rapidly clicks on and off — every few seconds while you're running water — it's short cycling, and it's one of the fastest ways to burn out an expensive pump. Each start hits the motor with a heavy electrical surge and heat, so cycling dozens of times a minute wears the system out in a fraction of its normal life. The cause is almost always a single component: the pressure tank.

Why it's urgent. A well pump should last 10–15 years. Left short cycling, it can fail in a small fraction of that — and spike your electric bill in the meantime. Diagnose it promptly.

Step 1: confirm it's short cycling

Watch the system pressure gauge or listen to the pump while someone runs a faucet. Normal operation: the pump runs, builds pressure, shuts off, and stays off until the pressure tank's stored water is drawn down. Short cycling: the pump snaps on and off every few seconds, never settling.

Step 2: understand the pressure tank

The pressure tank stores water under pressure so the pump doesn't have to run every time you open a tap. It does this with an air cushion (in a bladder tank, separated from the water by a rubber bladder). When that air charge is lost — the tank is "waterlogged" — there's no reserve, so the pump fires the instant you draw water and shuts off the instant you stop. That's the short cycle.

Quick test: tap the tank. A healthy tank sounds hollow on top (air) and solid at the bottom (water). A waterlogged tank feels heavy and sounds dull all over.

Step 3: check and reset the air charge

If the tank is waterlogged:

  1. Shut off power to the pump at the breaker.
  2. Drain the tank (open a nearby faucet or the tank's drain).
  3. Check the air valve on top with a tire gauge. It should read about 2 psi below the pump's cut-in pressure (e.g., ~28 psi for a 30/50 switch).
  4. Add air with a bicycle or air pump if it's low, restore power, and test.

If the tank won't hold air, the internal bladder has ruptured and the tank must be replaced.

Step 4: check the pressure switch

If the tank checks out but cycling continues, suspect the pressure switch — the component that tells the pump when to start and stop. Dirt, corroded contacts, or miscalibration cause erratic cycling. Have it cleaned, adjusted, or replaced (this is often a job for a well pro working on live electrical components).

Step 5: rule out leaks and a stuck check valve

A leak anywhere in the system — or a failing check valve that lets pressurized water bleed back down the well — drops pressure and makes the pump restart. If the tank and switch are good, have the well system inspected for leaks.

Stay ahead of it

Checking the well pressure tank periodically catches a fading air charge before it short-cycles your pump to death. While you're maintaining the well, keep up well water testing and the test well water quality task too. See the full well water system overview.

Make it automatic

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Frequently asked questions

Why is my well pump short cycling?+
Short cycling — the pump rapidly switching on and off — is most often caused by a waterlogged pressure tank that has lost its air cushion. The pressure tank stores water under pressure so the pump doesn't have to run every time you open a tap. When its air charge is gone (or its internal bladder has ruptured), there's no reserve, so the pump kicks on and off every few seconds. Other causes include a faulty pressure switch, a clogged or leaking system, or a stuck check valve.
Is well pump short cycling bad?+
Yes — it's one of the fastest ways to destroy a well pump. Each start draws a heavy electrical surge and generates heat; cycling dozens of times a minute wears out the motor, bearings, and pressure switch quickly and spikes your electric bill. A pump that should last 10 to 15 years can fail in a fraction of that if left short cycling. Fix the cause — usually the pressure tank — promptly to avoid an expensive pump replacement.
How do I fix a waterlogged pressure tank?+
First confirm it: tap the tank — a healthy bladder tank sounds hollow on top (air) and solid at the bottom (water), while a waterlogged one feels heavy and sounds dull all over. To fix, shut off power to the pump, drain the tank, and check the air valve at the top with a tire gauge. It should read about 2 psi below the pump's cut-in pressure; add air with a bicycle or air pump if low. If the tank won't hold air, its internal bladder has failed and the tank needs replacing.

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