Why Does My Water Pump Keep Switching On and Off? Causes, Symptoms & Easy Fixes

If your water pump has started clicking on and off every few seconds, you’re not alone! Short-cycling is one of the most common household water system issues—and luckily, it’s usually something you can diagnose (and often fix!) without too much stress. In this post, we’ll break down why your water pump keeps turning on and off, the signs to watch for, and the best solutions to get things running smoothly again.

Whether you’re dealing with a borehole pump, transfer pump, or booster pump, these tips apply across the board.

What Does It Mean When a Water Pump Short-Cycles?

Short-cycling happens when your pump switches on and off more often than it should—sometimes every few seconds, sometimes every minute or so. A healthy pump system should run for long, steady cycles, not rapid-fire bursts.

Why does this matter?
Because short-cycling can lead to:

• Higher electricity usage
• Premature pump wear
• Inconsistent water pressure
• Potential pump burnout

So spotting the signs early can save you from expensive repairs later!

Common Causes of a Water Pump Switching On and Off

Below are the most common reasons for short-cycling, explained in simple terms.

1. Low or Incorrect Air Pressure in the Pressure Tank

Your pressure tank (also called a bladder tank, diaphragm tank, or hydro tank) keeps water pressure stable. If the internal air pressure is too low, the pump kicks on constantly because there’s not enough cushion to maintain pressure.

Symptoms:

• Pump turns on every few seconds
• Very bouncy or fluctuating water pressure
• Tank feels “full” when tapped (a healthy tank has a hollow sound at the top)

Solution:
Use a pressure gauge to check the tank’s air charge.
Most setups require the tank to be 2 kPa below the pump’s cut-in pressure (often around 140–200 kPa depending on your system). Add air with a compressor if necessary.

2. Damaged or Waterlogged Pressure Tank

If the bladder inside the tank ruptures, water will fill the air chamber—leaving no cushion to control pressure.

Symptoms:

• Tank is heavy (full of water)
• Pump cycles rapidly
• Very little usable pressure

Solution:
Unfortunately, a waterlogged pressure tank usually needs to be replaced.

3. A Leak in the Plumbing System

Even a small leak can cause your pump to switch on and off as it tries to keep up with the pressure drop.

Symptoms:

• Pump runs even when no taps are open
• Constant dripping from pipes or joints
• Moist patches around buried or outdoor pipes

Solution:
Check for:

• Leaking taps
• Toilet cisterns running continuously
• Dripping garden hoses
• Buried pipe leaks

Fix or replace the leaking component.

4. Faulty Pressure Switch

The pressure switch tells your pump when to start and stop. If it’s worn out, clogged, or incorrectly set, your pump may behave erratically.

Symptoms:

• Pump won’t shut off
• Pump turns on and off too fast
• Pressure readings seem off

Solution:
Clean, calibrate, or replace the pressure switch. These are inexpensive and easy for a technician to swap.

5. Clogged Filters or Blocked Pipework

If your sediment filters, inline strainers, or borehole screens are clogged, pressure drops rapidly—triggering the pump constantly.

Symptoms:

• Weak flow at taps
• Pump cycling more than usual
• Dirty or sandy water

Solution:
Replace or clean filters regularly. Most should be serviced every 3–6 months.

6. A Failing Check Valve (Non-Return Valve)

A faulty check valve allows water to flow backward into the source, reducing pressure and signaling the pump to turn back on.

Symptoms:

• Rapid pressure drop when pump stops
• Pump restarts within seconds
• Gurgling sounds in the pipework

Solution:
Replace the check valve—an affordable fix with big impact.

How to Troubleshoot a Pump That Keeps Switching On and Off

Here’s a simple step-by-step checklist:

1. Check the pressure gauge to see if pressure swings wildly.
2. Inspect the pressure tank—tap it to check for a hollow sound at the top.
3. Examine plumbing for leaks—including toilets and outdoor taps.
4. Clean or replace filters and strainers.
5. Reset or clean the pressure switch.
6. Inspect the check valve for backflow issues.

If the problem persists, it may be time to call a pump technician.

When Should You Call a Professional?

If you notice:

• Burning smell from the pump
• Loud banging or vibration
• Pump running continuously
• No water pressure at all

These are signs that the pump could be overheating or failing. A licensed pump technician can diagnose issues quickly, preventing costly damage.

Final Thoughts

A water pump that keeps switching on and off isn’t just annoying—it’s your system waving a warning flag. The good news? With the right troubleshooting steps, most causes of short-cycling are easy to identify and fix. Whether it’s a simple pressure adjustment or replacing a worn-out check valve, getting ahead of the problem will protect your pump, save electricity, and give you smooth, reliable water pressure again.