Pool Pump Making Noise? Here's What It Means

Your pool pump shouldn't be loud. If it's making grinding, screaming, humming, or rattling noises, something's wrong. The good news: most pump noises tell you exactly what's failing. The bad news: ignoring them makes the repair much more expensive.

Grinding Noise: Bad Bearings

A grinding or growling sound—especially one that gets worse over time—almost always means the motor bearings are failing. Pool pump motors have two sets of bearings (front and rear) that allow the motor shaft to spin smoothly. When they wear out, metal rubs against metal.

What causes bearing failure:

• Normal wear (most motors last 8-12 years)
• Water intrusion from seal leaks
• Florida humidity accelerating corrosion
• Running the pump dry (even briefly)

What to do:

Bearing replacement costs $150-$250 in labor, plus the cost of bearings ($20-$50). This is worth doing if your pump is under 8 years old. If it's older, or if there's rust and corrosion inside the motor, you're better off replacing the whole motor or pump.

Don't ignore this. A pump with bad bearings will eventually seize completely. At that point, you're looking at $400-$800 for a new motor, or $600-$1,500 for a complete pump replacement.

Screaming/Whining Noise: Cavitation

A high-pitched screaming, whining, or sucking sound means the pump isn't getting enough water. This is called cavitation—the pump is literally sucking air because it can't pull enough water through the system.

Common causes:

• Clogged skimmer or pump basket: The most common culprit. Check and empty them.
• Dirty filter: A filter that hasn't been cleaned in months restricts flow. Clean or backwash your filter.
• Closed or partially closed valves: Someone may have turned a suction valve. Check all valves are fully open.
• Air leak in suction line: Cracked pipes, loose fittings, or a bad pump lid o-ring can let air in.
• Water level too low: If the water is below the skimmer opening, the pump sucks air.
• Undersized plumbing: Sometimes a pump is too powerful for the existing pipes (usually after an upgrade).

What to do:

Start with the easy stuff: empty baskets, check water level, verify valves are open. If those are fine, check for air bubbles coming out of your return jets—that indicates an air leak somewhere in the suction side. Air leaks usually occur at the pump lid, drain plugs, or pipe fittings.

Cavitation damages the pump over time. The impeller and volute (the plastic housing around the impeller) get worn down, reducing efficiency. Fix the cause promptly.

Humming But Not Starting: Stuck Motor or Bad Capacitor

If your pump hums but the motor doesn't turn, two things could be happening:

1. Stuck Impeller

Debris (leaves, pebbles, toys, small animals) can get past the basket and jam the impeller. Turn off the power at the breaker, remove the pump lid, and try to spin the impeller by hand. If it's stuck, you'll need to remove the debris. Sometimes this requires taking the pump apart.

2. Failed Start Capacitor

Pool pump motors use a capacitor to provide extra starting torque. When the capacitor fails, the motor hums but can't overcome the initial resistance to start spinning. Capacitor replacement is a $50-$100 repair.

Warning: Don't keep trying to start a pump that's humming. The motor is drawing high current and will overheat, potentially burning out the windings. Turn it off until you can diagnose the problem.

Rattling or Vibrating: Loose Components

A rattling sound usually means something's loose:

• Loose base bolts: The pump mounts to a concrete pad with bolts. These can loosen over time.
• Loose motor mounts: The motor attaches to the wet end with bolts that can vibrate loose.
• Debris in the pump: Small rocks or broken plastic pieces bouncing around inside.
• Worn rubber feet: The vibration dampening feet deteriorate in Florida sun.

Tighten everything you can. If the rattle is internal, you may need to open the pump and remove debris or replace worn parts.

Clicking Noise: Thermal Overload

If your pump runs for a while, then clicks off, waits a few minutes, clicks back on, and repeats—that's the thermal overload protector cycling. The motor is overheating.

Causes:

• Low voltage from the electrical supply
• Clogged motor vents (dust, dirt, spider webs blocking airflow)
• Bad bearings creating excessive friction
• Undersized wiring running long distances
• Motor running too many hours per day

Clean the vents on the motor housing first. If that doesn't help, have an electrician check your voltage and wiring.

When to Repair vs. Replace

Repair makes sense when:

• The pump is under 8 years old
• The motor housing isn't corroded
• Repair cost is less than 50% of replacement cost
• It's a simple fix (capacitor, bearings, seal)

Replacement makes sense when:

• The pump is over 10 years old
• There's visible rust or corrosion
• Multiple components are failing
• You want to upgrade to a variable-speed pump (saves 60-80% on electricity)

At Central Florida Pool & Spa, we give honest recommendations. If a $150 repair will give you another 5 years, we'll tell you. If you're throwing money at a dying pump, we'll tell you that too. Learn more about our pool repair services and equipment replacement options.

Quick Diagnostic Reference