How Often Should I Backwash My Filter? How Long?

I’m wondering how often should I backwash my filter? And how long should I backwash it for?


  1. Reply

    The Secret to Backwashing Your Filter is to Backwash Longer, but Less Often!

    Many pool owners backwash weekly as part of their maintenance routine. However, it’s not necessary to backwash that frequently! The ideal time to backwash is when the pressure shown on your filter gauge reaches 3-5 psi (pounds per square inch) higher than your normal running pressure.

    This may sound odd, but allowing some dirt to sit in the filter sand actually helps to create rough edges so the sand can catch small debris. Backwashing too often can stir up the sand and allow small particles to pass through the filter and back into the pool.

    A sand filter should always be backwashed for a minimum of 3 minutes and a maximum of 5 minutes depending on the size of the filter. Backwash for at least 3 minutes, even if the water leaving the backwash line or the water in the site glass is clear. Sometimes the filter sand will have a clear patch in it where no or very little debris has been trapped. Since the water pushes the debris from the bottom of the filter to the top of the filter, if backwashing is stopped at a clear patch, the debris underneath it forms a barrier in the sand and the filtration can no longer perform at its full potential.

    I hope this helps!

  2. Ryan


    Thanks! That answers my question.

Ask a Question or Comment