The Filter system has four cells that may be operated individually or in any combination. The flow rate is designed for 600,000 gal/day. The Filter is the gravity/pressure type and uses sand and anthracite as the filter mediums. Backwashing is accomplished in individual cells using filtered water from adjacent cells. The Filters are used all of the time to produce the highest quality of water. The Filters are bypassed only if the filter system is overloaded, less than 1% of the time.