7 Reasons Why Your Pool Pump Is Not Pulling Water from Skimmer (And How to Fix!)

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Owning a pool provides endless summer fun.  But as pool owners know, it’s not always smooth sailing to keep the water crystal clear.

Water chemistry is often one of the top priorities when it comes to pool care.  However, sometimes other situations may arise that could jeopardize the sparkling water.

One scenario that should not be taken lightly is if you notice that the pool pump is not pulling water from the skimmer.  This immediately indicates that there’s an underlying issue that could compromise the cleanliness and health of your pool, and could actually lead to costly damage.

There could be several reasons why your pool pump is not pulling water from the skimmer.  In this post, we’ll run through a comprehensive list of possible causes and steps you can take to fix it.

Without further ado, let’s dive in!

How Does a Pool Skimmer Work?

Pool skimmers are a key part of your pool’s circulation and filtration system.  They are designed to keep the pool clean by removing floating debris –such as leaves, twigs and bugs– from the surface using the flow of water.

Skimmers are also often used to attach the vacuum hose so that you can clean the surfaces inside the pool.

The skimmer is a box-like container located at the upper surface of the pool and has a port at the bottom from where the pump pulls water. 

The skimmer assembly includes a hinged flap or weir that collects debris into a basket as water flows into the skimmer box.  The weir prevents the debris from floating back into the pool.  

The pool pump is critical in the skimmer’s operation, as it provides the flow of water across the weir.  Disruption of flow at the skimmer will prevent it from functioning as needed.

The skimmer generally serves as the first point of contact as water is being returned to the circulation system.  This means it will help prevent the pump basket and pool filter from getting clogged.

For the most part, the skimmer is fairly self-sufficient.  It simply requires routine emptying of the collection basket to ensure leaves and other items don’t hinder its performance.

How Much Water Flows Across the Skimmer

While skimmers require water to flow across, there’s not a one size fits flow rate.  The required flow depends on the size of the skimmer, pool, pump and plumbing lines.  Larger pools will likely be sized with a bigger pump and skimmer, which would yield a higher flow rate.

Generally though, a good rule of thumb is to aim for a flow rate of 8 to 10 gallons per minute (GPM) for each inch of weir width.  For example, if your skimmer has an 8-inch weir, you should aim for a flow rate of 64 to 80 GPM. 

However, it’s important to note that this is just a general guideline and you should refer to the manufacturer’s instructions for your specific skimmer to determine the recommended flow rate.

There are also ways to measure your pump flow rate if you’re looking to establish a baseline value.

Pool Pump Not Pulling Water from Skimmer?

If you notice that the pool pump isn’t pulling water from the skimmer, some concern is warranted.  Afterall, without the flow of water the skimmer won’t do its job of cleaning the water’s surface.  Even more, it could indicate a larger issue within your pool’s circulation system.  

Here are some of the more probable (and not so probable) causes that could prevent water from being pulled into the skimmer.

Skimmer Basket is Clogged

This one will be fairly obvious.  If you remove your skimmer cover and see a basket full of junk, this can prevent the pump from being able to pull water through.

A basket could become clogged if a large storm blows debris into the pool.  Or, it could become clogged through gradual collection of pollen, leaves and other debris.  

If the skimmer remains clogged for too long, it could cause your pump to run dry and become damaged.  This is particularly true if your pump inlet is fed solely from the skimmer and there’s no main drain.

Ultimately, this reiterates the importance of checking and emptying the skimmer basket periodically.  This is a quick and simple activity that simply requires you to pull the basket out of the skimmer box and remove the debris.

Skimmer Weir is Stuck

The weir is a flap that allows water to enter the skimmer box while preventing debris from exiting.  It will move up and down naturally with the pull of water from the pump.

If the weir is stuck in the up position, it can block water from flowing into the skimmer basket and into the pump.  If stuck for too long, it can act similar to a clogged skimmer and cause eventual damage to the pump.  

When this scenario occurs, the first sign may actually be a gurgling sound coming from the skimmer box.  This is caused by the pump pulling the last remaining water from the skimmer as the weir prevents more water from entering.  

A weir may become stuck due to a stick or other rigid object that becomes wedged behind it.  Or, the weir hinge could become worn and damaged.

If you find yourself with a stuck weir, take a close look for any objects that have become wedged and remove them accordingly.  Otherwise, if there’s no obvious object causing the issue, try to wiggle the weir a bit to dislodge it from the upright position and ensure it moves freely.  Monitor it for a while afterwards to ensure it continues to freely move.

Skimmer Line is Blocked

If you find that your pump is not pulling water from the skimmer and both the weir and basket look fine, then you may have a blockage in the skimmer plumbing line.  This blockage may not be visible depending on how far into the plumbing it sits.

The skimmer line can become blocked if leaves or other large objects have passed through the collection basket.  If you notice a hole in the collection basket, it’s important to replace it with a new one to minimize debris from entering the skimmer line.

If you suspect this to be your issue, let’s quickly look at how to unclog a pool skimmer line.

How to Unclog Pool Skimmer Line

If you have a blocked skimmer line, turn off the pool pump and remove the basket.  

If the clog isn’t too far down into the plumbing, you may be able to use a long pole to gently push on the blockage to break it apart into smaller pieces.  Turn the pump back on to ensure it’s cleared.

Many blockages can’t easily be reached, in which a bladder style hose jet may be able to help out.  This tool simply attaches to the end of your hose and expands to create a seal inside the plumbing line, which provides a forceful jet of water to dislodge the blockage.  

Otherwise, a shop vacuum may also be able to help suck the blockage from the line.  Try to create a tight seal where the vacuum nozzle enters the plumbing –rags stuffed around the hose can help provide a seal.

For truly stubborn blockages, a drain snake may be useful.  These work great for clearing drains inside the house, and are similarly useful for pool plumbing.  Challenges with the snake may arise if your skimmer line has 90 degree elbows, which could prevent the snake from moving further down the line.

Lastly, consider employing a professional to help clear a clogged skimmer line.  They may be able to pressurize the line with compressed air to force out the blockage.  If you attempt this yourself, be cautious of overpressurizing the plumbing as this could trigger a different set of costly repairs.

Air Leak

Pool pumps generally require consistent water to achieve and maintain its prime.  A primed pump will ensure that it continues to pull water from the suction lines, including the skimmer.  

A leak on the pump’s suction side can result in air being sucked in, causing the pump to lose its prime.  This may eventually prevent the pool pump from being able to pull water from the skimmer. 

Air leaks can occur in the pool pump, the skimmer, or the plumbing leading to the pump.

To fix an air leak, turn off the pool pump and inspect the entire system for signs of an air leak. 

The pump lid and o-ring are common culprits for air leaks.  Inspect them for damage or cracks and replace as needed.

If the pump checks out OK, look over the inlet piping to the pump.  Replace any cracked components or tighten any loose connections.  

Since pool plumbing is often underground, it may be difficult to visually inspect the entire skimmer line that runs to the pump.  However, a cracked suction-side pipe underground may result in water loss only when the pump is off.  You can perform a bucket test with the pump on and off to determine if you have a suction side leak.

Once you have identified and fixed the air leak, turn the pump back on.

Faulty Pump Impeller

The pool pump utilizes an impeller to move the water through the system.  The impeller is a wheel with blades that is spun by the motor.  The size of the impeller and speed of the motor are key factors in determining how much water flows through the pump.

Sometimes debris can make it past both the skimmer basket and the pump basket into the impeller.  This debris could clog the impeller and cause the pump to stop pulling water from the skimmer.

Over time, the impeller may develop cracks which could also cause similar issues.

Fortunately, the impeller is generally accessible without too much trouble.  Often the pump will have a clamp that allows access to the wet-side of the pump.  A diffuser plate is held in place by several screws that can be removed to access the impeller.  

Once you’ve uncovered the impeller, clear any debris out with a small screwdriver or pliers.  Check for any signs of damage to the impeller, and replace with an identical sized one if needed.  While the impeller is uncovered, spin it by hand to ensure it moves freely and without wobble.  If the impeller is seized or wobbles, it could indicate that the motor may require repair or replacement.

Re-assemble the pump and turn it back on to ensure water is flowing properly.

Low Water Level

Skimmer plates typically have arrows along the side to show where the ideal water level should be maintained.  In general, most skimmers are designed to operate best when the water level is about one-third to one-half up the plate.  

If the pool’s water level is too low, the weir will not sway as it should.  Eventually, the flow of water into the skimmer won’t be able to keep up with the pump’s suction.  This will cause air to mix in with the water, which could result in the pump losing its prime.

Without being fully primed, the pump might not be able to pull water from the skimmer.  If this situation continues for too long, the pump could overheat and become irreparably damaged.  

Fortunately, maintaining water level is as simple as a quick daily check to ensure it’s close to the arrows on the skimmer plate.  If it’s too low, you’ll want to add water in a timely fashion.  

If you find that you’re losing water quicker than just normal evaporation, you may need to investigate for a leak.

Pump is Rotating in the Wrong Direction

This scenario is probably the least likely, but is something to consider if you’ve eliminated all other potential causes.  

If your pool pump is rotating in the wrong direction, you may envision water spewing out of the skimmer rather than being sucked in.  However, in reality the pump may still pull water in, but at a greatly reduced flow rate to where the skimmer is no longer working.

If you’ve literally just replaced or rewired your pump and now see a lack of water flow, you’ll want to ensure wires have not been crossed.  Most pool pumps are single phase 120 or 220V which doesn’t generally pose risk for a motor to rotate in the wrong direction; however, check the electrical configuration inside the motor housing to ensure it’s aligned with your actual electrical rating.

Otherwise, if you have an existing pump and suspect its rotating in the wrong direction, it could be caused by a failing capacitor.  Most often a failed start/run capacitor will prevent the pump from even turning on, but in rare instances it could actually cause your pump to rotate backwards.

In order to determine whether the pump is rotating in the correct direction, you can perform a simple test:

1 – Ensure the electrical breaker to the pump is turned off.

2- Remove the motor housing cover.

3 – Locate the end of the motor shaft and mark it with a small piece of tape. 

4 – Turn the pump on and observe the direction of the motor shaft by looking at the piece of tape. 

5 – If the motor shaft is rotating in the wrong direction, it is likely that there is an issue with the wiring or the motor capacitor.

Final Takeaway

If you notice that the pool pump is not pulling water from the skimmer, it is definitely something that should be addressed quickly.  In some instances, it could result in the pump running dry leading to expensive damage.

Fortunately, several of the causes are easy to identify and to fix.  A clogged skimmer basket or low water level in the pool can be seen with a quick visual inspection.  However, a damaged skimmer line underground can be trickier to resolve and could require professional assistance.  

With a quick daily check of the pool, you can ensure the pump and skimmer continue to work in tandem allowing you to stay ahead of any issues that may arise.

Happy Swimming!

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