4 Reasons why your Pool Water isn’t circulating

Water circulation plays an important role in keeping algae out of your pool. But what happens when your circulation isn't as good as it should be? Here we go over 4 common reasons why your pool water isn't circulating and how to fix it.

#1: Low Water Level

The first and easiest problem to spot is a low water level.

Obviously, if there’s no water being pulled into the system, no water can circulate out. So if your water level is below your skimmer inlet – then you’ve found the problem.

However, just having the water a bit too low but not below the skimmer could still cause issues. Thsi can lead to inconsistent water behind the skimmer flap, causing some air to get sucked in and reducing the pump efficiency.

The fix is simple: make sure to fill your pool such that the water level is about midway between the top and bottom of your skimmer inlet (this is usually about midway up the tile line). This will make sure your system inlet as a constant flow of water.

Remember,  an average pool will lose 2-4″ of water per week from evaporation (and potentially more with lot’s of heat and swimmers).  So make sure to check your water level and fill as necessary.

#2: Skimmer Basket is Full

The job of the skimmer basket is to keep leaves and other debris from entering the system. And depending on what you have around your pool, your basket might get full pretty quickly.

As more debris collects, the flow into the inlet begins to slow, causing more air to enter the system and reduce the pump’s efficiency.

Once a week, make sure to check and empty out the skimmer basket to make sure water is flowing into the system well.


TipAiming your pool jets

To help get debris out of the pool and maximize water motion, you can take advantage of the Earth’s rotation! This is called the Coriolis Effect. In short, water will always want to move in the direction the earth is rotating. So in Northern Hemisphere, this is counter-clockwise (and that’s why water in toilets and drains spin the way they do).

You can take advantage of this by aiming your jets to push the water in a counter-clockwise directions towards the skimmer to move debris and leaves more quickly into the inlet (and save you the work of skimming them out by hand later).

Also, you can help the water circulate by aiming one jet up towards the surface to motivate debris, and the other downwards to keep water from becoming stagnant (see example diagram below).

#3: Pump Basket is Full

Your pump is the heart of the circulation system.  And keeping debris from entering the motor is important. That’s why your pump also has a basket to prevent anything from entering it.

Normally your pump basket should be relatively clean since the skimmer basket is the first line of defense against pool debris. But it’s not perfect. So when anything get’s past the skimmer basket, the pump basket will capture it.

Just like the skimmer, if the pump basket get’s full of debris it will slow overall water flow entering the motor. If the flow gets low enough, the water will begin to cavitate entering the motor and introduce air into the system. This disrupts the ability of the pump to efficiently pull and push water through the system.

To empty the pump basket, first the system must be turned off, simply remove the lid and remove the basket.  Once the basket is empty and before you put the basket back into place, it is a best practice to check the impeller. 

The impeller is what actually pulls the water thru the system.  To find the impeller, simply look into the bottom of the pump pot with the basket removed, and you will see an opening on the bottom, rear of the trap on the motor side.  Simply take your hand and reach down in there and see if there is any debris blocking the impeller, which will feel like a fan blade.  The impeller should move with a little effort.

#4: Filter needs to be backwashed

The filter is there to capture small debris that is too small to be captured by the skimmer and pump basket, as well as any algae that is in the pool.

The pressure gauge indicates how easily water is passing through the filter media. There always should be some pressure in the system since all filter media will have an affect on flow.

However, if the filter becomes too dirty the pressure will become quite high, and the pressure coming from the return jets will be quite low. When this happens, the filter will need to be cleaned through “backwashing”.

Backwashing is where the flow of the filter is reversed to remove buildup on the media. This is pumped out of the system (“to waste”) to remove the buildup and keep it out of the pool.

Your filter’s manufacturer will specify at what pressure it’s time to backwash your filter.

If you have a DE or Sand filter, it should be backwashed at least once per month, or more often if needed. 

If you happen to have a single cartridge system, then it’s best practice to clean the cartridge every 2 – 4 weeks.  

For a four cartridge system, it’s  best to clean the filters once every 4-6 months, regardless of pressure.  


If your system is experiencing water flow or circulation issues, check these 4 areas before assuming it’s a problem with your equipment. If you’ve checked the above items and you’re still having issues, consider reaching out to a pool service professional to diagnose the issue.

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