Well, three ... kinda. One is just for laundry. One is the old original for the house. The tank is good but the drain field was marginal during super wet periods (like hurricanes). I had a remote drain field installed (old field was original from 1970) and kept the old tank as a settling tank which runs into the new tank which includes a pump to pump to the new drain field (higher ground and completely new drain field) which is on the opposite side of the pool which I had removed.