Well Pump Cycles On and Off Frequently: Causes & Fixes

Click-hum-click-hum-click... If your well pump sounds like it's doing cardio, you've got a problem. Short cycling—when your pump turns on and off every few seconds or minutes—is one of the most damaging conditions for your well system.

The good news? The cause is usually straightforward, and the fix often doesn't require replacing the pump itself. Let's diagnose what's happening and get your system running properly again.

⚠️ Why This Matters: Every pump start draws 4-7 times normal current, generating heat and wear. A pump designed to cycle 6 times per hour running at 60+ cycles per hour can fail in months instead of decades. Address short cycling immediately.

Quick Diagnosis Guide

Pump cycles every few seconds: Waterlogged pressure tank (most common)
Pump cycles every 1-2 minutes: Low tank air charge or small tank
Random erratic cycling: Pressure switch problems
Cycling during heavy use only: Undersized tank or high demand
Cycling when nothing is running: Leak in the system

Understanding Short Cycling

Short cycling occurs when your pump turns on and off more frequently than normal—sometimes every few seconds or minutes instead of running for several minutes per cycle. A healthy well system should cycle perhaps 1-6 times per hour during normal use, running for at least one minute each cycle.

The problem is mechanical stress. Every time your pump starts, the motor experiences inrush current (much higher than running current), capacitors fire, windings heat up, and bearings take load. The pressure switch contacts arc slightly with each cycle, gradually wearing the contact surfaces. Even the pipes experience stress from pressure cycling.

Frequent cycling wastes electricity, wears out pump components prematurely, stresses your electrical system, and can burn out your motor. A pump that should last 15-20 years might fail in 3-5 years with severe short cycling.

Cause #1: Waterlogged Pressure Tank

The most common cause of short cycling—accounting for probably 70% of cases—is a failed or waterlogged pressure tank. Understanding why requires knowing how pressure tanks work.

How Pressure Tanks Should Work

Your pressure tank contains a rubber bladder or diaphragm that separates water from compressed air. When the pump runs, water fills the bladder and compresses the air. When you open a faucet, the compressed air pushes water out without the pump running. This "drawdown" capacity is what prevents constant cycling—you can use several gallons before pressure drops enough to trigger the pump.

What Goes Wrong

Over time, the bladder or diaphragm can fail—developing pinhole leaks, tears, or complete rupture. When this happens, water floods into the air chamber. Without that air cushion, there's no drawdown capacity. Opening a faucet drops pressure immediately, triggering the pump. Closing the faucet lets pressure rise instantly, shutting off the pump. The result: rapid cycling measured in seconds.

How to Test for Waterlogging

Turn off power to the pump at the circuit breaker
Open a faucet to relieve system pressure
Locate the air valve (Schrader valve, like on a car tire) on top of the tank
Press the valve core briefly with a small tool
Check what comes out:
- Air only = tank may be okay (check pressure)
- Water spray = tank is waterlogged (bladder failed)

You can also tap on the tank. A properly working tank sounds hollow at the top (air space) and solid at the bottom (water). A waterlogged tank sounds solid throughout. Some people describe it as knocking on a wall versus knocking on a door.

The Fix

For bladder tanks, you may be able to replace just the bladder—typically $50-$150 for the part plus labor. For diaphragm tanks or if the bladder isn't replaceable, the entire tank needs replacement. A new 40-80 gallon pressure tank installed typically costs $300-$800. Learn more about your options in our bladder vs diaphragm tank guide.

Cause #2: Incorrect Air Pressure

Even if the bladder is intact, incorrect air pressure in your tank causes cycling problems. This is often overlooked because people assume a working tank doesn't need attention.

The Right Air Pressure

Your tank's air pre-charge should be set 2 PSI below your pressure switch's cut-in setting (the low number). Common configurations:

30/50 pressure switch: Tank air charge should be 28 PSI
40/60 pressure switch: Tank air charge should be 38 PSI
50/70 pressure switch: Tank air charge should be 48 PSI

Checking and Adjusting

Turn off the pump and open a faucet to drain pressure
Use a tire pressure gauge on the Schrader valve
Compare to your cut-in pressure minus 2 PSI
Add air with a bicycle pump or compressor if too low
Never add air with water pressure in the tank—you'll damage the bladder

Pro Tip: Check your tank's air charge annually as part of routine maintenance. Air slowly leaks past valve seals over time. A 5-minute check can prevent cycling problems before they start.

Cause #3: Pressure Switch Problems

The pressure switch controls when your pump turns on and off based on system pressure. When the switch fails or malfunctions, erratic cycling results.

Common Pressure Switch Issues

Pitted or corroded contacts: The electrical contacts inside the switch arc slightly with every cycle. Over thousands of cycles, this creates pitting and corrosion. Eventually, the contacts don't make solid connections, causing stuttering starts and erratic behavior.

Debris or insects: The pressure sensing port connects to your plumbing. Sediment, scale, or even insects can block this port, giving false pressure readings. The switch might think pressure is low when it isn't, or vice versa.

Incorrect settings: If the cut-in and cut-out pressures are too close together (less than 15 PSI apart), the pump cycles frequently even with a working tank. The adjustment nuts can also work loose over time, changing settings gradually.

Testing and Fixing

With power off, you can open the pressure switch cover and inspect the contacts. Pitted, blackened, or rough contacts indicate wear. Light pitting can be cleaned with fine sandpaper or an electrical contact file. Heavy damage means replacement.

Pressure switches are inexpensive ($20-$40) and relatively easy to replace for those comfortable with electrical work. Make sure the replacement matches your desired pressure range. Learn more about control boxes and switches.

Cause #4: System Leaks

If your pump cycles even when no water is being used, you likely have a leak somewhere in the system. The leak causes slow pressure loss, triggering the pump to maintain pressure.

Finding Leaks

Running toilets: The most common household leak—check all toilets by listening or using dye tablets
Dripping faucets: Even small drips accumulate
Irrigation system leaks: Check valve boxes and sprinkler heads
Hot water tank pressure relief valve: May be dripping into a drain
Underground pipe leaks: Look for unexplained wet areas in yard
Check valve failure: Allows water to flow back down the well

Leak Test Method

Close the valve between your pressure tank and the house
Watch the pressure gauge on your tank
If pressure drops with the valve closed, the leak is between the well and the valve (check valve, piping, tank fittings)
If pressure holds, the leak is somewhere in your household plumbing

Cause #5: Check Valve Failure

The check valve prevents water from flowing backward down the well when the pump stops. When it fails, water drains back, pressure drops, and the pump cycles to repressurize—only to have the water drain back again.

Symptoms of check valve failure include pressure that drops slowly after the pump stops, air spurts from faucets when first opened (air entering as water drains back), and cycling that occurs most noticeably after the pump has been off for a while.

Check valves are typically located at the pitless adapter or in-line near the pressure tank. Replacement is straightforward but may require draining part of the system. For submersible pumps, there's often a check valve at the pump itself that requires pulling the pump to replace.

Cause #6: Undersized Pressure Tank

Some systems were installed with pressure tanks that are simply too small for the household's water demand. This is common in older installations or when homes have been expanded with additional bathrooms.

The rule of thumb: provide 1-2 gallons of drawdown for every GPM of pump capacity. A 10 GPM pump needs a 44-62 gallon tank (which provides 14-22 gallons of drawdown). If your tank is undersized, the pump cycles frequently even when everything is working correctly.

The solution is upgrading to a larger tank. For high-demand homes, you can also install multiple tanks in parallel to increase total drawdown capacity. See our pressure tank sizing guide for details.

Troubleshooting Checklist

Step-by-Step Diagnosis

Check tank air valve — Water from valve = waterlogged tank
Check tank air pressure — Should be 2 PSI below cut-in
Inspect pressure switch — Look for pitted/corroded contacts
Test for leaks — Close house valve and watch tank pressure
Check all toilets — Running toilets are common leak sources
Verify tank size — May be undersized for current demand
Listen for check valve issues — Pressure drop when pump stops

When to Call a Professional

Some cycling issues are DIY-friendly—replacing a pressure switch or adding air to a tank are straightforward repairs. However, call a professional when:

You're not comfortable working with electrical components
The tank needs replacement (proper sizing and installation matter)
You suspect the pump itself is failing
The check valve in the well needs replacement (requires pulling equipment)
You've tried basic fixes and cycling continues
There's an underground leak you can't locate

Frequently Asked Questions

Why does my well pump turn on and off every few seconds?

Rapid cycling every few seconds almost always indicates a waterlogged pressure tank. When the tank's air bladder fails or loses its air charge, there's no cushion to maintain pressure between pump cycles. The pump turns on, pressure rises instantly, pump shuts off, pressure drops immediately, and the cycle repeats. This is hard on your pump motor and can burn it out.

How do I check if my pressure tank is waterlogged?

With the pump off and pressure relieved, push the air valve on top of the tank. If water sprays out, your tank is waterlogged. You can also tap the tank from top to bottom—a good tank sounds hollow at top (air) and solid at bottom (water). A waterlogged tank sounds solid throughout or has the water/air levels reversed.

Can a bad pressure switch cause short cycling?

Yes. A failing pressure switch may read pressure incorrectly, causing erratic on/off behavior. Contacts can become pitted or corroded, creating inconsistent connections. The pressure settings may also have drifted. Try adjusting or replacing the switch—it's a $20-40 part and simple repair before assuming the tank has failed.

How often should a well pump cycle on and off?

A healthy well system should cycle 1-6 times per hour during normal use, with each cycle running for at least one minute. If your pump cycles more than 6 times per hour or runs for less than 30 seconds per cycle, you have a problem that needs attention. The more frequent the cycling, the faster your pump will wear out.

Will short cycling damage my well pump?

Yes, significantly. Each time your pump starts, the motor draws high inrush current (4-7 times running current), generating heat and stressing electrical components. The pressure switch contacts also wear from repeated arcing. A pump that should last 15-20 years might fail in 3-5 years with severe short cycling. Fixing the cause promptly is essential.

Pump Cycling Problems?

Don't let short cycling destroy your pump. Our technicians can diagnose the cause and fix it—often the same day. Service throughout San Diego and Riverside Counties.

Call (760) 463-0493 for Service

Well Pump Cycles On and Off