Concerns regarding public health came to the forefront in the mid 1970's when numerous private septic systems failed in the central area of McKinleyville. Studies by the state proved that the cumulative septic discharge had exceeded that area's treatment capacity. MCSD was directed to resolve the problem by building a community collection system and interconnecting with a proposed regional treatment facility.

In 1978, MCSD worked with Humboldt County to form an assessment district to fund the construction of a sewer collection system for a four thousand acre area running from McCluski Hill on the south to Airport Road on the north. Initially, MCSD collected waste from 1,600 customers and pumped it to Arcata for treatment.

In 1983, however, MCSD secured grant funding and low interest loans to construct the treatment facility located north of Hiller Road. This facility has been remarkably cost effective to operate.

Today the District has approximately 6000 active sewer customers located in the sewer service area. Residential customers pay a base fee each month plus a variable fee on the first 12 ccf water they use each month for sewer service. Commercial customers pay a fee based on water consumption and the load characteristics of their use type. The District's collection system now includes approximately 65 miles of sewer mains. See the link below for the current rate structure.