The Los Osos sewage treatment plant is up and running, and the county held a grand opening Friday to celebrate the end of years of planning and construction.
The public was invited to eat cake, enjoy refreshments and tour the facility at 2270 Los Osos Valley Road, behind Los Osos Valley Memorial Park cemetery.
The completion of the treatment plant is one of the last stages of a $183 million project to install a sewer system that will serve 4,500 homes in a “prohibition zone” of Los Osos where septic tanks must be removed because nitrates have been contaminating the groundwater.
New development has been prohibited in the zone since 1983 until a sewer system was installed. After four decades of political controversy and planning challenges, construction on the sewer project began in 2012, and since then 50 miles of sewer pipeline have been installed and the treatment plant has been built.
The first homeowner in Los Osos hooked up to the new sewer system March 28 in a landmark moment featuring a ceremonial first flush. Over the next year, property owners throughout Los Osos will be connecting to the system and decommissioning their septic systems.
Once fully operational, the plant will process 1.2 million gallons of sewage per day.
The plant replaces the community’s longstanding use of septic systems with a new sewage treatment system that will provide recycled water that may be injected back into the groundwater basin or used for irrigation at local parks, schools and farms.
Objections to the sewer project originally planned by the Los Osos Community Services District included opposition to a proposed location for the treatment plant in midtown Los Osos next to the library and community center. Construction started there in 2005 before a recall election changed majority control of the Los Osos CSD’s board of directors and the project was halted.
The county then took over the design and construction of the new system, relocating the treatment plant.