Safety first: Turn off power and relieve system pressure before working on leaks.

Identify leak source: Dry the pump and run it briefly while observing. Determine whether water is leaking from the shaft area, housing joint, or pipe unions.
Union leaks: Tighten unions by hand plus a small additional turn with a strap wrench. Replace flattened or cracked union O-rings with Calpeda-compatible seals.
Housing joint leaks: If water seeps from the joint between the pump housing and motor adapter, remove the pump wet end and inspect the housing O-ring or gasket. Replace if damaged and reassemble evenly.
Shaft seal leaks: If water drips from under the motor or around the shaft, the mechanical seal is likely worn. Remove the impeller and replace the mechanical seal with a Calpeda-specified seal kit, ensuring clean, oil-free installation.
Cracked housing: For visible cracks in the volute or lid, replace the entire housing. Temporary sealants are not reliable under pump pressure.

Pump housing or surrounding area is leaking water while pump is running

Possible Causes