We are reader-supported. When you purchase through links on our site, we may earn an affiliate commission. Learn more.

If air bubbles are flowing from the return nozzles in your pool, you are dealing with a common problem. The problem usually occurs when the pool is put into operation in the spring. It is often related to the fact that the pipes were not properly resealed when they were screwed shut.

There are no direct negative consequences of the air bubbles in the pool, but with our tips you can easily get rid of the air bubbles and your pool will no longer bubble away.

The cause of air bubbles in the pool

The trigger is air getting into the suction side of the pump (that is, before the water is filtered). If you see air bubbles in the pool pump, it is a clear sign. There are a total of three places where air can get into the filter circuit.

Possible Cause #1: The Skimmer

One common cause is a water level that is too low. If the pool has too little water and the level of the water is well below the center of the skimmer’s opening, then the skimmer is also sucking in air.


  1. Check the water level and add more water to the swimming pool if necessary.
  2. Check the basket float to make sure it is not damaged and the water is being drawn in properly.
  3. Check the filter flap of the skimmer. Such a flap prevents large foreign objects from getting into the filtration system. It can happen that something gets caught here or the flap gets stuck on it.

Possible Cause #2: The Pump

If you see air bubbles in the pool pump, it doesn’t mean the pump is to blame. In this case, all three causes are possible.

However, your pool’s pump is another point of contact with water. And air can get into the circuit here, too. The reason may be that the pump cover is damaged or badly dirty. A poorly fitting or missing O-ring can also cause air bubbles in the pool water.


  1. Turn off the pump.
  2. Check the pump cover. If the lid is not tight, air can be sucked in. This may be due to heavy debris or a poorly fitting lid.
  3. Check the O-ring. If there is damage, debris, or simply a lack of the O-ring, you must take action. The best way to test the O-ring for cracks is to bend it between your fingers. Replace the O-ring if it is broken, rotten or dried out.
  4. Reposition the O-ring so that air can no longer find its way into the pool pump. You can use lubricant to create an even better seal.
  5. Check the pump basket. If the basket is damaged, it will often not seal properly with the housing. You will need to replace a pump basket with damage. Continue to make sure that the basket is cleaned regularly and is always inserted so that the lid can be closed airtight.
  6. Check the drain plugs. Make sure the drain plugs are tightened and tight. You can use sealing tape in addition to make an even better seal.

Possible cause #3: The connector

In 9 out of 10 cases, one of the first two causes or a connector is the reason for the air bubbles in your pool. It can get really costly if an underground connector is causing problems. In practice, however, this happens very rarely.

The connectors between pipes and the filtration system are other weak points in your pumping and filtration system. Systems with the joints are very advantageous because it allows individual parts of the water circuit to be replaced without having to cut through solid metal pipes.

However, the tightness of the connectors is not always guaranteed, so sometimes air can get in. O-rings ensure proper sealing here as well. Especially often, the connecting piece between the pump and the suction pipe is the cause.


  1. First check from the outside if one of the connecting pieces does not seal completely. You may even be able to notice air flowing in.
  2. Turn off your pool pump and unscrew the connectors one by one. Start with the pipes you last screwed or the pipe on the suction side of the pool pump, as this is often the cause.
  3. Check the O-ring. Again, you will need to replace damaged, porous, dried out and rotted O-rings.
  4. When screwing, make sure that the O-ring is properly seated in the notch (groove) provided. Only when the O-ring is in the groove is the connector airtight and air cannot enter.

Tips to avoid air bubbles in the pool.

  • If you have been working on the filter system piping and notice air bubbles in the pool shortly after, one of the connections is probably not quite tight.
  • With an ozone system, air bubbles in the pool are normal.
  • Sealing tape can be a temporary solution. In the long run, you should check the possible causes individually and install new O-rings if necessary.
  • When the pool is put into operation, the problem is usually too low water level. Due to the still missing water, air comes through the skimmer into the pool pump.

We hope that you were able to find the cause and that there are no more air bubbles in the pool water. Now you can swim in the pool again and without the involuntary whirlpool feeling.

Larry has been a true water rat since childhood. Pure pleasure turned into a passion. That's why he is the first point of contact for friends and acquaintances when it comes to pool-related problems. He is an integral part of the PoolHandbook editorial team.