SC By SCWS Team | February 3, 2026 | 10 min read
Well Pump Short Cycling: 7 Causes & How to Fix
Is your well pump turning on and off every few seconds? That clicking sound from your pressure switch—on, off, on, off—isn't just annoying. It's a warning sign called "short cycling" that can burn out your pump motor, spike your electric bills, and leave you without water at the worst possible time. Let's diagnose exactly what's causing your pump to short cycle and how to fix it.
⚠️ Don't Ignore Short Cycling
- • Each pump start uses 3-5x more electricity than running
- • Frequent starts overheat motor windings, causing premature failure
- • A $200 pressure tank problem can become a $3,000 pump replacement
- • Short cycling pumps typically fail within 2-3 years instead of 10-15
What Is Well Pump Short Cycling?
Short cycling occurs when your well pump rapidly turns on and off instead of running through complete, normal cycles. Here's what normal vs. short cycling looks like:
✅ Normal Pump Operation
- • Pump runs 1-2+ minutes per cycle
- • 4-6 cycles per hour maximum
- • Consistent pressure between cycles
- • Quiet operation between starts
- • Pump stays off when no water used
🚨 Short Cycling Signs
- • Pump runs only seconds at a time
- • Cycles every 30 seconds to 2 minutes
- • Rapid pressure fluctuations
- • Constant clicking from pressure switch
- • Pump runs even with no water use
The 7 Most Common Causes of Short Cycling
1. Waterlogged Pressure Tank (Most Common - 60-70% of Cases)
Your pressure tank contains an air bladder that acts as a cushion, storing pressurized water so your pump doesn't have to run for every glass of water. When this bladder fails or loses its air charge, the tank becomes "waterlogged"—full of water with no air cushion.
🔍 How to Diagnose a Waterlogged Tank
- 1. Tap test: Tap the tank from bottom to top. A healthy tank sounds hollow at top, solid at bottom. Waterlogged tanks sound solid throughout.
- 2. Pressure check: Turn off pump, drain all water, check air valve with tire gauge. Should read 2 PSI below cut-in pressure (28 PSI for 30/50 system). Zero or very low reading = failed bladder.
- 3. Feel test: A waterlogged tank often feels cool and sweaty all over, not just on the bottom portion.
The fix: If the bladder is intact, you may be able to recharge the air ($75-$150 service call). If the bladder has failed, you'll need a new pressure tank ($400-$1,500 installed). Learn more about pressure tank replacement costs.
2. Pressure Tank Too Small for Pump
If your pressure tank is undersized for your pump's flow rate, it can't store enough water between cycles. This is common when homeowners add bathrooms or irrigation without upgrading the tank, or when a larger pump was installed without matching the tank size.
Pressure Tank Sizing Guidelines
| Pump Flow Rate | Minimum Tank Size |
|---|---|
| Up to 10 GPM | 20 gallons |
| 10-20 GPM | 30-44 gallons |
| 20-35 GPM | 60-86 gallons |
| 35+ GPM | 86+ gallons or multiple tanks |
The fix: Install a larger pressure tank or add a second tank in parallel. This is especially common in San Diego County homes that have added ADUs, guest houses, or extensive landscaping irrigation.
3. Faulty Pressure Switch
The pressure switch tells your pump when to turn on (at cut-in pressure, typically 30 PSI) and off (at cut-out pressure, typically 50 PSI). When the switch malfunctions, it may:
- Bounce contacts: Dirty or corroded contacts cause erratic on-off cycling
- Wrong pressure settings: If cut-in and cut-out are too close together, cycles are too short
- Clogged sensing port: Sediment blocks the small tube that reads water pressure
- Failed diaphragm: Internal diaphragm ruptures, causing erratic readings
⚡ Safety Warning
Pressure switches involve 240V electricity. If you're not comfortable working with electrical systems, call a professional. At minimum, turn off the breaker before inspecting the switch.
The fix: Clean the contacts with fine sandpaper, clear the sensing port, adjust the settings, or replace the switch entirely ($150-$350 for service and parts).
4. Failed or Leaking Check Valve
Check valves are one-way valves that prevent water from flowing back down into the well when the pump stops. Most well systems have at least two: one at the pump (submersible wells) and one at the pressure tank.
When a check valve fails:
- Water drains back down, losing pressure
- Pump must run again to rebuild pressure
- Cycle repeats endlessly
- You may hear water "falling" or gurgling after pump stops
The fix: Replace the faulty check valve. The above-ground tank check valve is an easy $200-$400 repair. If the pump check valve has failed (requiring pulling the pump from the well), costs increase to $800-$2,000+ depending on well depth.
5. Plumbing Leak in the System
Any water loss between the well and your fixtures causes pressure drops that trigger the pump. Common leak locations include:
- Running toilets: The #1 culprit—a silent toilet leak can waste 200+ gallons daily
- Dripping faucets: Even small drips add up to pressure loss
- Underground pipe leaks: Often hidden, may show as wet spots in yard
- Water heater T&P valve: Sometimes drains unnoticed through discharge pipe
- Irrigation system leaks: Broken sprinkler heads, cracked valves
🔍 How to Find Hidden Leaks
Turn off all water fixtures. Watch your pressure gauge. If pressure slowly drops with nothing running, you have a leak. Shut off the supply to each fixture one by one to isolate the source.
The fix: Find and repair the leak. This might be as simple as replacing a toilet flapper ($10) or as complex as repairing an underground pipe ($500-$2,000+).
6. Well Running Low on Water
If your well's water level has dropped below the pump intake, the pump will start, fail to build pressure (because it's pumping air or very little water), shut off on low pressure, then repeat as water slowly seeps back.
Signs your well is running low:
- Short cycling happens mainly during heavy use periods
- Water sputters or spits air when running
- Problem is worse during drought or summer
- Full pressure returns after letting well "rest"
- Neighbors report similar issues
The fix: Options include lowering the pump, deepening the well, hydrofracturing to improve yield, or installing storage tanks. See our guides on wells running out of water and slow well recovery rates.
7. Pump or Motor Problems
Sometimes the pump itself is the problem. Worn impellers, failing bearings, or overheating motors can cause erratic operation:
- Worn impellers: Can't build full pressure, pump runs but never reaches cut-out
- Thermal overload trips: Motor overheats, internal switch cuts power, cools, restarts
- Failing capacitor: Weak starts, motor struggles to reach full speed
- Electrical issues: Voltage drops, loose connections, corroded wires
The fix: If the pump has been short cycling for a while, it may already be damaged. Have a professional test amp draw and diagnose. Pump replacement costs $1,500-$3,500+ for submersible pumps. See our well pump replacement cost guide.
🔧 Quick Diagnostic Flowchart
Step 1: Does pump cycle with all fixtures off?
→ YES: Leak in system or failed check valve
→ NO: Continue to Step 2
Step 2: Tap on pressure tank. Same sound top to bottom?
→ YES (solid throughout): Waterlogged tank
→ NO (hollow at top): Continue to Step 3
Step 3: Check tank air pressure (with tank empty)
→ Zero or very low: Bladder failed, replace tank
→ Correct pressure: Continue to Step 4
Step 4: Does water sputter or contain air?
→ YES: Low well water level or pump issue
→ NO: Likely pressure switch or undersized tank
Repair Cost Summary
| Cause | DIY Possible? | Professional Cost |
|---|---|---|
| Recharge pressure tank | Yes (with tire gauge/compressor) | $75-$150 |
| Replace pressure tank | Difficult | $400-$1,500 |
| Adjust/replace pressure switch | If comfortable with electrical | $150-$350 |
| Replace above-ground check valve | Moderate difficulty | $200-$400 |
| Replace pump check valve | No | $800-$2,000 |
| Fix plumbing leak | Depends on location | $50-$2,000+ |
| Lower pump / well work | No | $1,500-$5,000+ |
| Replace well pump | No | $1,500-$3,500+ |
When to Call a Professional
While some short cycling causes are DIY-friendly, call a professional if:
- You're not comfortable with electrical systems (pressure switches use 240V)
- The pressure tank bladder has failed and needs replacement
- You suspect the pump itself is damaged
- The check valve at the pump needs service (requires pulling the pump)
- Your well may be running low on water
- You can't identify the cause after basic troubleshooting
- The problem has been going on for weeks (pump may already be damaged)
Preventing Future Short Cycling
Keep your well system running smoothly with these preventive measures:
✓ Annual Inspections
Have a professional check pressure tank pre-charge, pressure switch condition, and system performance yearly
✓ Monitor Cycle Times
Pay attention to how often your pump runs—catching short cycling early prevents pump damage
✓ Check Tank Air Pressure
Annually check and adjust bladder tank pre-charge with a tire gauge
✓ Fix Leaks Promptly
Running toilets and dripping faucets cause unnecessary pump cycles
Frequently Asked Questions
What is well pump short cycling?
Short cycling is when your well pump turns on and off rapidly, often every few seconds to a minute, instead of running for several minutes at a time. Normal pump operation involves running 1-2 minutes minimum before shutting off. Short cycling wastes energy, wears out your pump prematurely, and often indicates a system problem that needs attention.
What is the most common cause of well pump short cycling?
The most common cause is a waterlogged pressure tank. When the air bladder fails or loses its air charge, there's no air cushion to maintain pressure, causing the pump to cycle on with every small water draw. This accounts for roughly 60-70% of short cycling cases.
How do I know if my pressure tank is waterlogged?
Check by tapping on the tank—a waterlogged tank sounds the same solid thud all the way up, while a healthy tank sounds hollow at the top (where air should be). You can also check the air pressure at the valve stem with a tire gauge when the tank is empty. It should read 2 PSI below your cut-in pressure (typically 28 PSI for a 30/50 system).
Can short cycling damage my well pump?
Yes, short cycling significantly damages your pump. Each start draws 3-5 times more electricity than running, creating heat stress on motor windings. Frequent starting also wears out the pump's mechanical components faster. A pump that should last 10-15 years may fail in 3-5 years due to chronic short cycling.
How much does it cost to fix well pump short cycling?
Costs vary by cause: recharging a pressure tank costs $75-$150, replacing a pressure tank costs $400-$1,500, adjusting or replacing a pressure switch costs $150-$350, and fixing a check valve costs $200-$500. If the pump itself has been damaged from short cycling, replacement costs $1,500-$3,500+ depending on depth and pump size.
My pump short cycles only when no water is being used. Why?
This indicates a leak in your plumbing system or a failed check valve. When no fixtures are running but pressure still drops, water is escaping somewhere—either through a running toilet, leaking pipe, dripping faucet, or backwards through a faulty check valve into the well. This is actually the system working correctly to maintain pressure, but addressing the leak is essential.
How often should a well pump cycle normally?
A properly sized system should cycle no more than 4-6 times per hour during normal use. Each run cycle should last at least 1-2 minutes. If your pump is cycling more than once per minute during use, or cycling at all when no water is being used, there's a problem that needs diagnosis.
Can I fix short cycling myself or do I need a professional?
Some fixes are DIY-friendly: recharging a bladder tank's air pressure, adjusting pressure switch settings, or fixing a running toilet. However, replacing pressure tanks, servicing check valves, or diagnosing complex issues typically requires professional help. If you're unsure of the cause, it's best to call a well professional to avoid making the problem worse.
Pump Short Cycling? Let's Fix It Before It Gets Worse
Don't let a minor issue turn into a major pump replacement. Our technicians can quickly diagnose the cause of your short cycling and provide a cost-effective repair. We serve all of San Diego and Riverside Counties with same-day emergency service available.
