The town granted a variance because the design meets its intended purpose and protects the environment much better than our previous system. The system was placed in service June, 1995. Any system this complex has many possible failure modes. Ground water can leak into the system. Pumps can fail.
Power outages can occur.
Float switches can stick open or closed. The overflow tank can fill. Pipes can clog. Any of the five controller relays can fail. In the winter there is nobody around.