DIY Fixes for Air Bubbles in Your Pool Return

The only bubbles you want to see in your swimming pool are those produced by your pool bubbler. If you’re seeing them in your pool return, there’s a problem somewhere in the filtration system, and that could spell a disaster down the line, with the pool pump needing repairs and major issues with water quality looming. So how does one solve the problem of air bubbles in the pool return?

To fix the fault of air bubbles in your pool return, it is necessary to identify where in the system it is leaking. The three most likely areas are the weir, skimmer box, pool pump, or the joints in the inlet pipe before the pump. Once identified, the repair is relatively simple.

The pleasure of owning a pool and enjoying relaxing, exercising, and playing in its cool water during a long, hot summer is balanced to an extent by the need to maintain it. Parts wear out, the water needs to be kept free of harmful impurities, and regular cleaning is an unavoidable chore. Bubbles in the pool return is a common fault, but fortunately, an easy one to fix, so let’s identify the steps.

How To Fix Air Bubbles In The Pool Return

By process of elimination, we can quickly identify where the air is getting into the system and causing bubbles to appear at the pool return outlet. Having done that, repairs may involve replacing a worn component, tightening a connection, or just patching a hole.

Check The Skimmer Box, The Most Likely Cause

Water is drawn from the pool into the system at the skimmer box, so this is the first possible source of unwanted air. It’s also the most likely, being the most exposed to potential damage by activity in the pool. Large pools may have two skimmers, but for this article, I’m assuming that there’s only one.

Firstly, check the water level of your pool. If it’s lower than halfway up the skimmer box, there is a chance that air will be sucked in with the water. If necessary, no repair is required – just top up the pool to the required level.

The next step is to ensure that the skimmer weir, or skimmer flap, which is designed to prevent large pieces of debris from getting into the skimmer pipe, is moving freely. Sometimes that debris gets trapped, and the weir hinders the flow of water.

Empty the skimmer basket, removing leaves, twigs, and other debris which might block the skimmer pipe and reduce the flow of water to the pump.

Check The Pump And All Its Components

Once you’ve got the skimmer working correctly and the bubbles continue to appear, the next area to inspect is the pump. It’s probably the hardest-working piece of equipment in the whole system, so it’s possible that some part has worn or is broken and is letting air into the system. Switch off the pump, cut the power supply for the sake of safety, and carry out the following checks:

Check the lid for cracks. If the pump basket has been allowed to get too full, the lid covering it is placed under too much pressure, and it cracks and may need to be replaced.

Check the pump basket, which also cracks if overfilled or has become brittle through age. There’s no point in trying to repair it – just buy a new one.

Check the O-ring, the rubber seal which prevents air from entering the pump between the pump lid and the basket holder. This is a very likely culprit, as it becomes cracked and brittle over time. If it’s in good condition, just remove any dirt or debris, lubricate it with petroleum jelly, and replace it. If it shows any sign of wear, buy a new O-ring – they’re inexpensive.

Check The Drain Plugs which you will find on the pump housing and which may be loose or leaking. The plumber’s tape around the threads should seal these plugs.

Check the pump itself, if all other components are in good shape, and if it’s still sucking in air. It’s possible that the impellers are worn and need to be replaced, or it could be a faulty valve or damaged seal, although this is not often the cause of air getting into the system.

Check The Pipes And Joints

The chances are that by thoroughly inspecting the skimmer and pump, you will have picked up the leaks in the system, and the bubbles in the pool return will have disappeared. If that’s not the case, however, there’s one more area to inspect, and that’s all the piping in the suction section of the system.

You’ll find several sections of piping, with various elbows and unions, which are designed to make removal of the filter easier if it becomes necessary, and also to configure the system to tie in with other external factors such as plant beds, rocks, and other landscaping features.

With each union, check the tightness of the joint, check that threads are not crossed and that the pipes are not cracked. Use the plumber’s tape again on the threads, PVC weld on any cracks, and replace any of the small O-rings that seal every joint and may be cracked.

Prime The Pump And Run To Check The System For Bubbles

Having done all the checks and carried out any necessary repairs and replacements, I can confidently predict that the problem has been solved. Remember to prime the pump before switching it back on to avoid overheating it, and then check for bubbles at the return outlet.

There may be a few residual pockets of air in the system, but the bubbles should quickly disappear. If this is not the case, there’s a more serious problem, and I recommend that you get in a professional to investigate as it now becomes beyond the ability of the average home handyman to sort it out.


Fixing air bubbles in the pool return is relatively simple once the source of the unwanted air intake has been established. Almost always, the fault is to be found in the skimmer, the pump, or the plumbing, and the repairs involve cleaning out debris, replacing worn or broken parts, or improving seals.