5 Things to Know About When to Backwash a DE Filter

Backwash based on pressure, not a calendar schedule. The only reliable indicator is the pressure gauge reading, not a fixed day of the week or month.

Know your filter’s clean startup pressure. This is typically 10-15 psi. Write it down so you have a baseline to compare against.

Backwash when pressure rises 8-10 psi above startup. That 8-10 psi jump signals the filter is loaded. This might happen every two weeks in summer or every six weeks in spring.

Backwashing on a fixed schedule wastes water and DE. You flush out good filter media too early, and the cleaning is no better than waiting for the pressure rise.

Backwashing too often prevents proper DE cake buildup. Without that cake, fine particles slip through your filter, reducing water clarity.