Air Bubbles in Pump or Return Jets

Why You See Air in the Pump Basket or Coming From the Return Jets

Seeing bubbles inside the pump lid or in the pool’s return jets is one of the most common pool system symptoms. In most cases, it means air is entering the system somewhere on the suction side (from the skimmer to the pump). Small bubbles are usually minor, but constant or heavy bubbles signal a problem that should be corrected.

This guide explains the causes and what you can check before requesting service.

⭐ 1. Water Level Too Low (Most Common)

When the water level drops below the midpoint of the skimmer opening, the skimmer begins pulling air + water instead of water only.

Signs:

• Bubbles blowing out of return jets
• Skimmer making a “slurping” noise
• Pump basket not staying completely full

Fix:

• Raise the water level until it reaches halfway up the skimmer opening
• Make sure the skimmer weir door swings freely

This alone fixes more than 50% of bubble issues.

⭐ 2. Skimmer or Pump Baskets Clogged

Debris restricts water flow and causes the pump to pull air.

Check:

✔ Skimmer basket packed with leaves

✔ Pump basket has debris or hairline cracks

✔ Skimmer socks overly dirty

Fix:

• Remove and clean all baskets
• Inspect for cracks—replace if damaged

⭐ 3. Pump Lid O-Ring Issue

The pump needs an airtight seal. A bad O-ring allows air to enter.

Possible problems:

✔ O-ring is dry, flattened, or cracked

✔ O-ring not seated correctly

✔ Pump lid not tightened fully

✔ Dirt or debris around the lid

Fix:

1. Turn pump off
2. Remove pump lid
3. Clean the O-ring and lid groove
4. Apply pool-safe silicone lubricant
5. Reseat and tighten the lid firmly

If bubbles disappear afterward, the O-ring was the issue.

⭐ 4. Suction-Side Air Leak (Underground or Above Ground)

Any suction leak before the pump will draw air into the system. These typically require professional inspection.

Possible leak points:

• PVC unions
• Cracked pipe at pump inlet
• Fittings at skimmer
• Suction valve O-rings
• Underground suction lines

Signs:

• Large bubbles from return jets
• Pump struggles to stay primed
• Air returning after being bled out
• Loud whistling or hissing near pump

Fix:

• Check unions for tightness
• Inspect for visible cracks
• If air continues, contact us for diagnostics

⭐ 5. Air Leak From Vacuum or Suction Cleaner Hose

Vacuum hoses often develop tiny leaks.

Check for:

✔ Loose hose sections

✔ Old hoses with pinholes

✔ Missing O-rings where hoses connect

Fix:

• Reconnect hose sections securely
• Replace aged or cracked hoses
• Make sure the hose stays fully submerged

⭐ 6. Dirty or Clogged Filter

When pressure rises due to a dirty filter, water flow drops, and bubbles may appear.

Fix:

• Clean cartridge
• Backwash (if using sand or DE)
• Ensure pressure returns to normal

⭐ 7. Newly Plastered Pool (Normal)

If your pool was recently resurfaced:

✔ Micro-bubbles are normal for the first few days

✔ The curing and startup process releases air

These disappear on their own.

⭐ 8. When Bubbles Are a Serious Issue

Contact Professional Pool Company if you notice:

✔ Pump losing prime

✔ Bubbles getting worse over time

✔ Loud noises from pump housing

✔ Water leaking around pump inlet

✔ Return jets spitting bursts of air

This may indicate:

• A significant suction leak
• Bad pump shaft seal
• Undersized plumbing
• Cavitation
• Cracked fitting underground

We can identify and repair the root cause.

⭐ Summary

Air bubbles in your pump or return jets usually mean:

• Water level too low
• Baskets clogged
• Pump lid O-ring not sealed
• Vacuum hose leak
• Suction-side plumbing leak

Small bubbles = often harmless

Large or constant bubbles = system problem that needs correction

⭐ Need Help?

If bubbles persist after basic checks, contact Professional Pool Company. We can troubleshoot suction leaks, pump issues, or plumbing problems to restore proper flow.

Updated on: 29/11/2025