Why You Have Air Bubbles In Your Pool

Written by Michael Dean
April 3, 2024

air bubbles in a swimming pool

You love your pool. Its calm, cool waters are a refreshing sight on a hot day, and you can’t wait to dive in! But wait a second… Why do you have air bubbles in your pool? And what is that aggressive grinding sound that seems like it’s coming from the pump?

While a few bubbles here and there are completely normal, if you’re seeing a lot of bubbles, you have a problem. Luckily, it’s usually an easy one to solve.

Below, I’ll cover what air bubbles in your pool mean, how they got there, and what you can do to fix them.

Main Takeaways

  • If you have a lot of air bubbles coming out of the return jets, it means there’s air in the pool line.
  • Air can get into your pool’s water lines due to: low water levels, loose strainer pot lid, compromised/damaged o-rings, or compromised unions.
  • To get rid of the air bubbles, you must check the water level, check the skimmer basket, look at the pump and pump basket, and examine the unions.
  • If you still see air bubbles after troubleshooting, call a professional.

Why Air Bubbles Are a Bad Sign in Your Pool

A few air bubbles here and there are normal in any pool, but if you see a lot of air bubbles coming from the return jets and hear angry churning noises near the pump, it can only mean one thing: There’s air in the pool line.

Finding air in a pool’s water line is a common problem, especially if you just opened up your pool for the season. Several issues can create these air bubbles, but we first need to understand a few pool basics to solve them.

The Inner Workings of Your Pool

Every pool has a pump. As a pool owner, you probably know this, but you may not understand how the pump works. Allow me to give a brief explanation.

The pump pulls water from skimmers along the side of the pool as well as from the main drain. The skimmer, by the way, looks like a hollow box and sits just below the rim of your pool. It’s the hole all the pool noodles get sucked toward, in case you need further clarification.

After being pulled through the skimmer, water runs through a filter known as a strainer pot, where large debris like leaves are filtered out.

From there, the pump pushes the pool water into a finer filter, which takes care of bacteria and smaller dirt particles. This finer filter is usually filled with diatomaceous earth or sand that filters out these impurities.

After that, the water runs through the heater. Then it goes through your salt-chlorine generator before being pushed back into your pool via the return jets.

If air bursts out of those return jets, it means there’s air in the water line instead of just water. Your job now is to figure out how it got there so you can fix the problem. If you think the problem is with the return jets, head to my guide on troubleshooting when your pool return jets aren’t working.

The Reasons Behind The Bubbles

Now that you have a basic idea of how your pool works, let’s focus on fixing the problem at hand. There are a few ways air can get into a pool’s water lines:

  • Low Water Levels
  • Loose Strainer Pot Lid
  • Compromised or Damaged O-Rings
  • Compromised Unions

Luckily, you can solve most of these issues with a bit of elbow grease and a simple DIY fix. Fixing a pool may sound intimidating, but don’t worry; I’ll walk you through the process step by step.

How to Get Rid of Air Bubbles in Your Pool

To get rid of air bubbles in your pool, you’ll need to do some troubleshooting. Here we’ll start by looking at the most basic fixes. If none of them work, you may need to call in a professional for help with more technical solutions.

Check the Water Level

Low water levels in your pool cause the skimmer to suck in air instead of water. If the skimmer sucks in air, you’ll see air bubbles burst from the return jets down the line.

In general, water levels need to be at least halfway up the skimmer. If the water in your pool is lower than that, simply adding more water should fix the air bubble problem.

Skimmer Solutions

After checking that the water level is adequate, check the skimmer basket. It can compromise water suction if it’s not seated correctly or damaged or clogged.

While you’re at it, check the weir. The weir is the door that sits on the front of the skimmer. Sometimes it gets jammed, which leads to poor water suction.

If water suction is compromised, you can end up with air in your pool lines and air bubbles in your pool.

Look at the Pump

Once you’re sure the skimmer is working correctly and the water level is spot on, it’s time to look at your pool’s pump.

Start by looking at the pump’s lid. If it’s cracked, that’s your problem. Replacing the pump lid will likely solve your air bubble issues.

More commonly, it’s not the pump lid but the o-ring inside it that’s compromised. To check the o-ring, you’ll need to turn off the pool’s pump and remove the lid.

Run your fingers along the o-ring inside the lid. It should be flexible and smooth.

If there are any signs of rot or damage, replace it! An O-ring is inexpensive, and you can absolutely replace it yourself.

If it’s not cracked, damaged, or dried out, it’s still a good idea to spray the o-ring with a Teflon-based o-ring lubricant. That will prevent it from drying out in the future and helps create a tight seal.

Check out my research on the most reliable pool pumps if you need to replace the entire unit.

Don’t Forget the Pump Basket

Now that the pump lid is open, look at the pump basket. If it’s not seated correctly, your pump lid can’t seal correctly, causing air to enter your pool lines. Unfortunately, when a pump basket isn’t level, it’s usually cracked, and you’ll need to replace it.

Next, look at the pump’s housing. On it, you should see a drain plug or two. Make sure the drain plugs are not loose or leaking. If they are, you can try applying plumber’s tape to create a tighter seal.

Examine the Unions

We’ve ruled out the skimmer and the pump, so now it’s on to the unions. Unions are threaded connection points that allow pool owners to replace pool equipment without cutting pipes.

They’re great when pool equipment needs to be replaced or repaired, but they can also be a source of trouble. Loose unions allow air to enter the pool lines, causing your pool bubble problem.

To check the unions, you first want to be sure the pool pump is off. Then, remove the nut covering the union.

Inside each union is an O-ring. If the o-ring is cracked, dry, or damaged, you’ll need to replace it. Compromised o-rings block tight seals and can allow air into pool lines.

Even if it’s not damaged, it may not be sitting correctly. Run your fingers along the o-ring. Is it sitting in its groove? Is there any dirt or debris? If the o-ring is out of place or anything is in its way, it won’t seal correctly.

Once done, reconnect the union. Make sure it closes all the way so the ridge is tight to the back of the nut, or you’ll only add to the air bubble problem!

When Air Bubbles Persist

If you’ve checked the skimmer, pump, and unions but still see air bubbles, you might have a bigger plumbing problem at hand.

Suction-side leaks can also cause air bubbles. These leaks may occur in your main drain or your side skimmer, but either way, the problem’s too big for most non-professionals to handle without outside help. At this point, it’s best to call in a professional.

Here’s the good news, the issue rarely has to do with a leak in your underground plumbing. So, even if you have to call for help, it’s unlikely to be a costly or time-consuming repair.

That said, don’t prolong getting fixing the issue. Procrastinating your pool bubble problem could cause more severe damage to your pool’s equipment. You could end up with poor filtration, algae-laced water, or worse, a burnt-out motor (or extreme energy usage and corresponding bills).

In either case, that damage can mean an early end to swim season. That’s a risk no one should take!

Get My Free Pool Care Checklist

Download my free, printable pool maintenance checklist to help you accomplish regular pool care tasks for any type of swimming pool.

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Bubbles Belong in Bathtubs, Not Pools

You have every right to be concerned when you see air bubbles in your otherwise perfect pool. A few now and then might be no big deal, but generally, they don’t belong. And when accompanied by that terrible grinding sound from the pump, you know you have a problem.

Luckily, air bubbles are a common issue that most pool owners can tackle on their own. It might be as simple as adding more water to your pool or replacing an o-ring in your pump lid.

So if you see air bubbles in your pool, don’t fret! Troubleshoot those bubbles and get back to swimming fast.

Any questions? Shoot me a note.

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