The San Marcos Interceptor Sewer project replaced the Vallecitos Water District’s 1960’s era, 21 inch diameter, sewer interceptor with 42 inch fiberglass reinforced pipe trunk sewer main. In this phase, 3600 linear feet of pipe was placed, along with 200 linear feet of 72 inch microtunnel, 7 to 10 foot diameter sewer manholes, 10 MGD bypass, and ground dewatering. 

Construction consisted of building 3400 feet of 42 inch Fiberglass Reinforced Pipe Trunk Sewer Main, 13 each, 8 foot diameter manholes and 1 each, 12 foot diameter manhole. In addition, a portion of the project was micro-tunneled under a 40 foot wide box culvert, requiring extensive sheet pile, and beam and lag shoring on a major road. The project conveys sewer from the intersection of Via Vera Cruz through a sensitive, biological channel easement, and terminates at San Marcos Blvd. The existing trunk sewer required a high volume (10million GPD) bypass system consisting of an 18 inch diameter fused HDPE bypass line, with multiple 8 and 12 inch diesel driven pumps.

The completion of Phase 2 of the San Marcos Interceptor Project has been in the works for more than 30 years.