Why should a filter be drained if it is going to be out of service for an extended period?

Draining a filter that will be out of service for an extended period is crucial to avoid algal growth. When water is left stagnant in a filter, it creates an ideal environment for algae and other microorganisms to thrive. Warm temperatures, coupled with light exposure, can promote the rapid growth of algae, which can lead to a host of problems when the filter is eventually put back into operation. Algal blooms can clog the filter media, affect the water quality, and potentially contribute to foul odor and taste issues in the treated water.

In contrast, operational efficiency, filter life, and cleaning the filter media are important considerations, but they do not directly address the specific risks associated with standing water in a filter. By draining the filter, the risk of biological growth is significantly reduced, ensuring that when the filter is brought back online, it operates effectively and does not introduce contaminants into the water distribution system. This step is essential for maintaining the overall quality and safety of treated water during prolonged periods of inactivity.