In 1973, the California Regional Water Quality Control Board (RWQCB) prohibited the use of septic systems within several areas based on significant concerns that improperly operating septic systems threatened the quality of the ground water. Sewering of these areas was thought to be the best solution; however, feasibility studies found that this was not cost effective. As an alternative, in 1982, the County adopted an ordinance establishing DMAs. With the creation of the ordinance, septic systems were again allowed under enhanced County control.