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Troubleshooting

Seal Bubbles, Geysers, Underground Fitting Leaks, and Water After Shutdown

Learn how to distinguish a rotor seal leak, broken swing assembly, underground fitting leak, low-head drainage, and seeping irrigation valve.

Updated August 5, 2026 Hunter HydroTech LLC Michigan Irrigation Knowledge Center

Water around a rotor can come from several locations. Correct diagnosis depends on whether the leak occurs while the zone is running, immediately after shutdown, or long after the system should have drained.

Leak while running

A worn top seal may create a small bubble around the riser or a severe geyser.

Leak from below the head

  • Cracked nipple
  • Punctured swing pipe
  • Leaking swing elbow
  • Damaged CRE or CRT
  • Cracked zone line

Water after shutdown

A low head may drain water remaining in the lateral line. A Hunter I-20 check valve may help in suitable applications.

Water long after shutdown

If the system has had time to drain and the head continues leaking, the irrigation valve may be seeping because of debris, diaphragm wear, or internal damage.

Frequently Asked Questions

Why does my rotor bubble around the top while running?
A worn riser seal may allow a small bubble or severe geyser around the top of the head.
Why does one sprinkler leak after shutdown?
It may be normal low-head drainage or it may indicate a valve that is not closing completely.
How can I tell whether the valve is seeping?
If the head continues leaking long after the zone should have drained, the valve should be inspected.

Professional Irrigation Service

Need help diagnosing your sprinkler system?

Hunter HydroTech provides residential and commercial irrigation repair, pump-system service, valve diagnosis, controller troubleshooting, backflow service, revamps and seasonal maintenance throughout Southeast Michigan.

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