pool pump humming but not working

Are you hearing humming noises from your pool, but the pump doesn’t start?

Humming noises are one of the many signs of a fault in the motor as it means that your motor is starting but not working properly. The pump needs to work to enjoy quality time in the pool with your family and friends as it is the most fundamental part of the pool.

Due to the pool pump humming but not working, you would not have the pool water running and clean. Taking timely action to fix the pool pump can save you from major damage, such as replacing the system.

Why is my Pool Pump Humming and Not Working?

If you wonder, “why does my pool pump just hums” it signifies a restriction in the normal functioning of the pump. There could be several reasons, but to understand them properly, let’s tell you about the anatomy of the pool pump first.

Anatomy of the Pool Pump

The pool pump is a complete system composed of different parts that facilitate the flow and pressure of water in your swimming pool. The five major components of a pool pump include:

Pump Lid
As the name indicates, it is the lid of the pool pump that you can lift to inspect the health of your pump easily. It is the first inspection location in case of a leak or cracks or when your pump loses prime suddenly. It is one of the primary locations for air to enter the system and cause problems like pool pump motor humming but not turning on.

Pool Pump Replacement Lid
Pool Pump Replacement Lid

Strainer Basket
The strainer basket is placed to keep the water clean and collect all the debris before reaching the suction line.

Pool Pump Strainer Basket Replacement
Pool Pump Strainer Basket

The impeller is the driver of the whole pump as it pumps the water from the pool to the filter to keep it clean and safe for swimming. The impeller is placed in the pump housing center along with diffuser and rubber seals.

Pool Pump Impeller
Pool Pump Impeller

Shaft and Motor
The shaft and motor of the pump make it possible for the impeller to run and cause water movement and filtration.

Drain Plug
The drain plug is an outlet that enables you to drain the pump conveniently.

Read what troublefreepool.com had to say about “pool pump makes humming noise and does not pump”

Pool pump motor humming but not turning

Now that you recognize the parts of the motor, you can identify the source of noise and apply the solution that suits your problem the best. If you are new to having a pool, it is worth knowing that experts recommend noticing the sounds and vibrations in the pump to indicate the presence of a possible fault. Here are some of the possible problems and their solutions if the pool pump not working just humming.


Blockage in the line due to debris is undoubtedly the most reason for pool pump humming but not running. Firstly, you must check the strainer baskets to see if the dirt clogs them or compromises their function. Besides the skimmers, the accumulation of debris might block the impeller from working and cause the pool pump to make humming noises.

Imbalanced Impeller

Other than a blockage in the most important part of the pump, the impeller may also be imbalanced if the pool pump humming won’t start. While checking why the water pump humming but not pumping, check the impeller as an imbalanced impeller can gradually cause massive damage. It can lead to a force imbalance and prove harmful to the system. You need a professional to evaluate an imbalance in the impeller if you suspect so.


The pressure of the liquid vapor in the pool should equal or be higher than the pressure of the liquid in the impeller. Pool pump humming noise may be due to increased impeller-liquid pressure. Due to high pressure, cavities form that result in vibrations in the system.

Misaligned/ Bent Pump Shaft

The shaft is a critical part of the pump, and any issue with the shaft results in high vibrations. Sometimes either the shaft is misaligned or bent. A bent towards the center causes relatively strong vibrations or humming noises. Get a professional to check and replace the shaft if needed.

READ MORE: 6 Best Automatic Pool Cover Pump


How can you tell if a pump capacitor is bad?

A malfunctioning pool pump capacitor is one of the causes of vibrations, and you can check the health of the capacitor by using a meter. Connect the leads of the meter to the capacitor terminals. A ZERO reading indicates a bad capacitor.

How to fix a bad capacitor?

If your pool pump humming not pumping, it may be due to a bad capacitor. Simply replace the capacitor and red rid of the humming noise.

Final Words

When the pool pump hums but not working, it may be due to a blockage, an electrical or mechanical fault, or just because the motor makes noise. Understanding the anatomy of the pump, you can evaluate the problem or get professional help if needed.

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