If your pool pump is running but your water isn’t circulating properly, a clogged or broken impeller might be the issue. The impeller is the part of the pump that moves water through the system, and when it’s blocked or damaged, the entire filtration system suffers. The good news? It’s usually easy to fix with the right tools and a little know-how.
This guide covers the most common pool pump impeller problems, how to troubleshoot them, and which products can help you fix or replace your impeller fast.
What Is a Pool Pump Impeller?
The impeller is a small spinning component inside your pump’s wet end that creates water flow. As it spins, it generates centrifugal force that pulls water in and pushes it through the filter and back into the pool.
When the impeller is clogged, cracked, or loose, your pump may run but won’t move water efficiently—or at all.
1. Clogged Impeller
What causes it?
Leaves, hair, small pebbles, or even pieces of broken plastic can pass through the strainer basket and clog the impeller vanes.
Direct Answer: A clogged impeller occurs when debris passes through the pump basket and blocks water flow inside the pump housing.
Signs of a clogged impeller:
- Low or no water flow from the return jets
- Pump is noisy but weak
- Filter pressure is abnormally low
- Air bubbles in the pump basket
Fix it:
- Turn off and unplug the pump.
- Open the pump housing and remove the impeller cover plate.
- Use a wire or small screwdriver to gently remove debris from the impeller.
- Reassemble and prime the pump before restarting.
Recommended Product:
Impeller Cleaning Tool Kit – Includes flexible picks and brushes designed to safely clear impeller vanes without damaging the housing.
2. Broken or Cracked Impeller
How does it break?
Over time, impellers can wear out from vibration, age, or exposure to chemical imbalance. If a foreign object gets lodged too forcefully, it can snap or chip the blades.
Direct Answer: Impellers break when debris damages the vanes or the plastic becomes brittle from age or chemical exposure.
Symptoms of a broken impeller:
- Pump is running loudly or vibrating excessively
- Very weak or zero water circulation
- Unusual grinding noise inside the pump
Fix it:
- Disassemble the pump wet end and inspect the impeller.
- If broken, replace the impeller with a matching model.
- Inspect the diffuser and motor shaft while you’re in there for additional damage.
Recommended Product:
Hayward Super Pump Replacement Impeller – OEM-quality replacement for common residential pumps. Choose the right horsepower to match your motor.
3. Loose or Stripped Impeller
What does that mean?
Impellers are threaded onto the motor shaft. If they come loose or the threads strip, the impeller won’t spin effectively—even if the motor runs fine.
Direct Answer: A loose impeller occurs when it detaches from the motor shaft or the threads strip, causing a loss of water movement.
What to do:
- Remove the impeller and inspect the threads on both the impeller and shaft.
- If stripped, replace the impeller and possibly the shaft seal.
- Tighten to manufacturer specs and use thread locker if advised.
Recommended Product:
Loctite Threadlocker Blue 242 – Prevents loosening of threaded impellers without permanently bonding parts. Safe for pool pump assemblies.
4. Impeller Shaft Seal Leak
What happens here?
The shaft seal keeps water out of the motor. If it fails, water can reach the motor bearings, causing rust, corrosion, or complete pump failure.
Direct Answer: A worn shaft seal lets water leak from the pump, leading to rusted motors and costly repairs.
Signs of a leaking shaft seal:
- Water under the pump motor
- Rust or corrosion on the motor housing
- Squealing or grinding motor noise
Fix it:
- Remove the pump and disassemble the impeller housing.
- Replace the shaft seal and inspect the impeller and seal plate for wear.
- Always use lube during installation to avoid tearing the new seal.
Recommended Product:
U.S. Seal PS-200 Pump Seal Kit – Industry-standard replacement for most pool pumps. Includes ceramic and rubber components for a watertight seal.
5. Improper Impeller Installation
Can you install it wrong?
Yes. If the impeller isn’t installed flush with the diffuser or the wrong size is used, the pump won’t create enough flow or pressure.
Direct Answer: An improperly installed impeller will reduce pump efficiency and can cause vibration or poor circulation.
Fixes:
- Double-check impeller model matches your pump motor’s horsepower.
- Ensure diffuser is properly aligned and not damaged.
- Reassemble pump carefully and test flow after installation.
Recommended Product:
Pentair Impeller and Diffuser Combo Kit – Matched parts designed for optimal performance. Includes diffuser, gasket, and impeller to ensure correct installation.
How to Prevent Pool Pump Impeller Problems
Routine maintenance goes a long way in preventing impeller issues:
- Clean pump baskets weekly: Stops debris before it reaches the impeller.
- Use a skimmer sock or leaf trap: Helps capture fine debris and hair.
- Monitor water chemistry: Unbalanced water can damage impeller plastic and seals.
- Listen for changes: New sounds or pressure drops often signal impeller trouble.
Recommended Product:
SkimDoctor 2.0 Skimmer Basket Insert – Turbocharges your skimmer’s ability to trap hair and debris before it reaches the pump impeller.
When to Call a Professional
While cleaning a clogged impeller is a DIY-friendly job, you should call a pro if:
- The motor is also damaged or leaking water
- You see cracks in the housing or seal plate
- You’ve replaced the impeller but still have no flow
Conclusion: Keep Your Pool Flowing Smoothly
The impeller may be small, but it plays a huge role in keeping your pool water clean and safe. A clogged, broken, or improperly installed impeller can lead to poor circulation, dirty water, and expensive repairs if ignored.
Experiencing low flow or pump problems? Use the steps and recommended products above to inspect, clean, or replace your impeller. With just a little maintenance, your pump can stay in top shape all season long.