How To Identify the Cause of Low Water Flow

This guide will walk you through the common problems related to low water flow in your pool circulation system.

1. Clogged pump strainer basket - Remove the strainer basket and clean debris out with a hose.

2. Clogged skimmer basket - Remove the skimmer basket and clean debris out with a hose.

3. Clogged filter - If your filter water pressure is creeping up to 10 psi above your filter's clean reading, the filter is clogging with too many contaminates and it time to clean it. Increasing pressure goes hand in hand with decreasing water flow.

4. Clogged impeller - If the pump's impeller is clogged with debris, water will not be able to flow out the side slots and generate a vacuum. Without a vacuum, the pump will not be able to suck as much water into the pump which reduces water flow. Remove the impeller and clean out the debris.

5. Too many features open - Are all the valves adjusted correctly? Too much equipment on at one time will stop many cleaners from working (waterfalls, spa jets, surface returns, etc.).

6. Undersized impeller - When you last replaced a motor, did you match the impeller (and possibly the diffuser) to the new motor? If you put in a larger motor, you may have an undersized impeller.

7. Air leak in suction side - A suction leak will reduce the vacuum generated in the pump which will reduce water flow and possibly lead to lose of priming in the pump.

8. Water leak in the pressure side of the pump - A pressure leak will cause lose of water and water pressure in the circulation lines between the pump and the pool return ports. Generally these leaks can be corrected by replacing a bad gasket in the pool equipment after the pump.

9. Pump too small - The pump suction cannot overcome the total dynamic head (line resistance) in your pool circulation system.

10. Underground leak - If you have an underground leak, you can dig up some of the lines yourself. However, for generally less than $100 to $200 you can have a professional come in with special detection equipment that will pinpoint your leak including areas under the pool that you can't get to. Costs to repair the leak will vary according to where it is.

If you have any other questions about pool and spa products please do let us know - we are here to help! 

Leave a comment