3 Things to Know About When to Backwash Your Pool Filter

Backwash only when the pressure gauge reads 8–10 psi above your clean starting pressure. A fixed schedule wastes water and DE because the filter gets dirty at different rates.

Check the pressure gauge weekly and note the clean pressure after each backwash. Also watch return flow—if it’s weak and pressure is up, it’s time to backwash.

DE filters are more sensitive than sand or cartridge types. Over-backwashing when pressure is barely up reduces filtration efficiency, so let the filter get dirty enough before flushing. Always add fresh DE after backwashing.