How to Backwash Your Sand Filter

Taking the time to backwash your sand filter is an important part of filter maintenance in order to prolong the life of your filter.

As your sand filter cleans debris out of your pool water, it collects the debris with its sand chamber, which adds pressure to the overall flow of water in the filter. Backwashing runs the water through your sand filter backwards, allowing all of the collected debris to exit the filter. The process of backwashing should typically be done every few weeks during the swimming season.

The pressure gauge on your sand filter will help indicate when it is time to backwash your filter. As the sand filter collects more and more debris, pressure will increase in the filter tank. When the pressure gauge shows a pressure of 8-10 psi over what your starting pressure was, you will want to backwash your filter. Below, we walk you through the steps on how to backwash your sand filter.

As with all piece of pool equipment, be sure to read the instructions that come with your sand filter. Some directions may vary slightly depending on particular model. If your filter did not come with one, you will need a backwash hose as well as a clamp to attach the hose to your filter.

7 Steps to Backwash Your Sand Filter

  1. Turn your filter’s pump off.

  2. Make sure that your backwash hose is properly attached and rolled out, with no kinks or bends. Some filters may require you to add this hose and clamp it on before backwashing.

  3. Turn your valve to the Backwash setting.

  4. Turn pump back on to start the Backwash cycle. This process can take 1 to 2 minutes depending on your filter and the amount of debris in your filter. If your filter has a sight glass, use it to visually gauge the backwashing. Debris will appear in the glass along with the water. When the water clears out enough with little to no debris showing, turn the pump off again.

  5. After the Backwash cycle, the sand in your filter is loose and not quite ready for filtering yet. The sand must be re-compacted. Set your filter’s valve to the Rinse cycle.

  6. Turn the pump on for a few moments. The Rinse cycle re-compacts the sand. Let this run for approximately 15-30 seconds, then turn your pump off once more.

  7. Your filter’s sand is now ready for filtering again. Set your filter’s valve to the Filter cycle. Restart your pump.