Is there a distinction between Best Available System for a Rebuild and a Best Available System required for a Major Addition?
If the results of the Field Clearance for a Major Addition reveals that the existing in-ground system is functioning adequately, but it may not meet current requirements for depth of soil below trench bottom, the addition of an approved pretreatment system to the existing in-ground system would be allowed (Best Practical System). In the case of a Rebuild, the Best Available System is required, which, in some instances, may require replacement of an existing in-ground system with an above ground system, if warranted, rather than the simple addition of a pretreatment unit to an existing system. A Rebuild is held to a higher standard of septic system upgrade than a Major Addition.
