Well Pump Short Cycling

What short cycling looks like

You open a faucet and hear the pressure switch click on, then off, then on again a few seconds later. The gauge needle swings up and down fast. In the shower, the pressure surges and sags in a steady rhythm. Some people notice it only as a rapid clicking from the basement or the well house.

The pump isn't supposed to work that way. Franklin Electric, a major submersible motor maker, says to run motors at least one minute per start so they can shed the heat from starting current. Its limit for single-phase motors up to 0.75 hp is 300 starts in 24 hours, and 100 starts for 1 to 5.5 hp single-phase motors. A pump that cycles every few seconds while you water the garden can blow through that in an afternoon.

Likely causes

Franklin's troubleshooting table for "motor starts too often" lists four causes: the pressure switch, a check valve stuck open, a waterlogged tank, and a leak in the system. Pentair's manual adds a fifth: the pressure switch mounted too far from the tank. In practice the tank is the one to check first.

1. 1

   Cause 1: Waterlogged pressure tank or low air charge

   A bladder or diaphragm tank holds a cushion of air above the water. That air is what lets the pump fill the tank and then rest while you draw water out. When the air charge leaks down, or the bladder tears and the tank fills with water, there's no cushion left. The pump fills the tank in seconds, shuts off, and the pressure crashes as soon as you open a tap.

   Two quick tells. Knock on the side of the tank: a good tank sounds hollow at the top. Then press the stem of the air valve on top for a second. Air should come out. If water spits out, the bladder has failed and the tank needs replacing. Pentair lists a waterlogged tank as a cause of the pump starting too often and says to check the precharge and the bladder.

   Our waterlogged pressure tank page goes deeper on bladder failure, and older air-over-water tanks without a bladder have their own fixes there.

2. 2

   Cause 2: Pressure switch set wrong or failing

   A switch with pitted contacts or a differential set too narrow can chatter on and off. Pentair lists a defective or misadjusted pressure switch as a cause and says to readjust or replace it. Franklin says the same. A clogged tube or nipple under the switch can do it too, because the switch sees pressure spikes the rest of the system doesn't. See well pressure switch problems.

3. 3

   Cause 3: A leak somewhere in the system

   If the pump comes on with every tap closed, water is going somewhere. Check toilets for a running flapper, look for drips at outdoor spigots, and listen at the tank. Pentair says to check tank connections with soapy water and that the system must be air- and water-tight. A leak in the drop pipe down the well won't show anywhere you can see, but the pressure will bleed down slowly between cycles.

4. 4

   Cause 4: Check valve stuck open

   The check valve keeps water from draining back down the well when the pump stops. If it sticks open, pressure drops after every cycle and the pump restarts. Franklin lists a check valve stuck open as a cause and says to replace it. On a submersible, the main check valve is often down the well, which makes this a pro job.

5. 5

   Cause 5: Switch too far from the tank

   Pentair says to mount the pressure switch within one foot of the tank. A switch at the end of a long run of pipe can read pressure swings the tank never sees.

Checks you can do safely

1. Turn off the pump breaker.
2. Shut the valve between the tank and the house, if you have one, and open a faucet near the tank to drain it until the house gauge reads zero.
3. Read the air pressure at the valve on top of the tank with a tire gauge.
4. Compare it with the switch setting printed inside the switch cover or on its label.

Pentair's rule is to set the tank's air precharge 2 psi below the pump cut-in pressure, measured with no water pressure on the system, and to check it every year:

If the reading is low, add air with a compressor or bike pump until you hit the target, then restore power and watch a full cycle. If the tank won't hold air for more than a few days, or water came out of the air valve, the bladder is done. Our guide to pressure tank air pressure walks through it step by step.

Jet pumps and pressure tank short cycling

Jet pumps sit above ground, so you can hear and see everything. The same causes apply: tank air charge, switch, and leaks. A jet pump with a leaky foot valve can also lose prime between cycles, which looks like short cycling mixed with sputtering taps. Our jet pump problems page covers those.

How to fix short cycling, by cause

• Low air charge, bladder intact: recharge the tank to the right pressure and recheck in a week.
• Water from the air valve or a tank that loses air again: replace the tank. See how to replace a well pressure tank.
• Chattering or pitted switch: replace the switch, then reset the tank to match. A steady hand can do it, and our pressure switch adjustment guide shows how the nuts work.
• Leak in the house: fix it, then watch whether the pump still restarts with every tap off.
• Suspected check valve or drop pipe leak: call a well contractor. Pentair's fix for a drop pipe leak is to raise the pipe one length at a time until water stands in it, then replace the pipe above that point. You need a pump hoist for that.

When to call a pro, and what it costs

Call a well contractor when the tank checks out fine and the pump still cycles, when the pump restarts with no water in use and you can't find a leak, or when the system needs the pump pulled. A pump that has short cycled for months may also have damage of its own. Our page on signs your well pump is going bad covers what to watch for.

HomeGuide's 2026 figures, parts and labor included:

HomeAdvisor puts the minimum house call at $100 to $150. If the tank turns out fine but the pump is worn, see well pump replacement cost.