Swimming Pool Blog

Cavitation & Swimming Pool Pumps

by Mark Garcia July 08, 2015

Cavitation in a swimming pool pump occurs when a pump is starved for water. It can happen when an oversized pool pump is installed on a system with 1.5" plumbing or a too-small pool filter.

Cavitating pumps make a particular growling sound, like the pump is gargling rocks, a low, grumbling sound. The water also won't usually fill up the pump basket.

A pump that cavitates also uses excessive amperage, resulting in wasted energy and high energy bills, and because it's overworking the motor, premature failure is likely.

But - a poor pump choice may not be the only reason a pump cavitates. Temporary cavitation can be caused by anything that obstructs or blocks water flow into the pump. Closed or broken directional valves or check valves, clogged impellers or skimmer pipes, or a very full pump basket can all cause cavitation in an otherwise normally operating pump. In this way, a cavitating pump can be an excellent diagnostic tool.

Here's a good example of a cavitating pump - a 2 hp Hayward Northstar pump, installed on a 1000 gallon baby pool. 1.5" plumbing and a tiny TR-40 sand filter. This pump is way oversized for the system - ha!



Avoid pool pump cavitation by resisting the V-8 mentality that a lot of pool owners have. You don't need a big pool pump, for optimum filtration and the lowest energy usage, select a pool pump that can deliver the correct amount of water flow, to match the filter design flow rate. Add 10%, so the pump will still be effective with a dirty filter, but go no larger!

For help selecting a new pool pump that won't cavitate - give our experts a call and let them do the math! 877-POOLCTR


Thanks for Reading!
Mark Garcia