What started as traditional upgrades to a regional water treatment plant, grew into something much more: a new way to make the most of precious water resources and secure a drought-proof supply of water that will support the Cayucos community for decades to come.

When the California Coastal Commission denied the request to upgrade the shared Morro Bay/Cayucos Water Treatment Plant and instead execute projects beyond the coastal area, the Cayucos Sanitary District was forced to explore new ways to serve its community.

WSC and the District worked together to envision a compliant solution that also benefits the community: build a new water resource reclamation facility beyond the coastal zone that creates a sustainable water supply from a previously disposed water resource and complies with the Regional Water Quality Control Board requirements.

The Cayucos Sustainable Water Project—a new .34 MGD greenfield water resource recovery facility—will create a locally controlled supply of high-quality water that will be used within the community for agricultural irrigation and offset demand for potable water. The facility also positions the community for future direct potable reuse, creating a local drought-proof water supply for the Cayucos and Morro Bay communities.

The relocated facility reuses an existing ocean conveyance pipe for treated effluent disposal. The Cayucos Sanitary District will lease an existing and already permitted pipeline, saving millions in costs that would be needed to construct a new pipeline to the site of the new facility just beyond the coastal zone. Value engineering further reduced costs by identifying $1.4 million in savings to construct the lift station needed to transfer water to the new site.

Successful coordination with regulators has advanced the project from decision to pursue to operation within just six years. The facility is on schedule to be operational in 2021.

WSC and the District’s project partnership began with project visioning and exploration of conceptual wastewater alternatives and facilities planning. MBR and UV disinfection treatment processes were then designed to meet state requirements for recycled water. WSC guided the District through the successful application for more than $25 million in grant and low-interest loan funding through the United States Department of Agriculture Rural Development and State Water Resource Control Board Water Recycling Facilities Planning programs.

In 2023, our partnership was recognized for excellence with the CWEA Tri-Counties Section Award for Engineering Achievement for the Cayucos Sustainable Water Project. This project, which began as traditional upgrades to the community’s wastewater treatment plant, has grown into a way to make the most of precious water resources and secure a drought-proof water supply for the community for decades to come. We are proud of our collaboration and teamwork that has delivered forward-thinking results for local, independent, sustainable, and resilient water resources for the community.

Video credit: Ashley & Vance Engineering, Inc.