OAR 340-071-0285: Redundant Systems

(1) Criteria for approval. Construction permits may be issued for redundant absorption field systems to serve single family dwellings on sites that meet both of the following conditions. (a) The lot or parcel was created before January 1, 1974. (b) The lot or parcel size will not accommodate a standard system. (2) Design criteria: (a) Each redundant absorption system must contain two complete absorption fields. (b) Each absorption field must be large enough to accommodate the projected daily sewage flow from the dwelling. (c) A minimum separation of 10 feet (12 feet center to center) must be maintained between absorption trenches designed to operate simultaneously, and a minimum separation of 4 feet (6 feet center to center) must be maintained between adjacent absorption trenches. (d) The system must be designed to alternate between the absorption fields with the use of a diversion valve or other method approved by the agent.