Community involvement was key from the start. In partnership with the City, WSC facilitated the development of a Program Charter that outlines a project scope and ensuring community values are reflected in the project’s outcomes.

After nearly 100 years of successful operation, San Luis Obispo’s Water Resource Recovery Facility is facing challenges familiar to water and wastewater agencies across the United States: increasingly stringent regulations, increased water demand amidst limited water resources, aging equipment and rising operations costs.

New nitrate limits from the State require changes to the facility’s methods of nutrient reduction. Knowing that upgrades to the facility’s treatment processes are needed, the City began to think beyond compliance and consider ways that the upgrades could provide lasting benefits to the community and surrounding environment.

Community involvement was key from the start. In partnership with the City, WSC facilitated the development of a Program Charter that outlines a project scope and reflects the input of the community. The Charter has guided project decisions from day one, ensuring that community values are reflected in the project’s outcomes.

Upgrades to the facility are now under construction and once complete, will provide significant long-term water quality, environmental and community benefits. The selected treatment process, membrane bioreactor (MBR) technology, does more with less—reducing nitrogen to less than 10 parts per million using less equipment and without requiring dechlorination.

MBR was also selected for the versatility it offers for future resource recovery—without future investment. With MBR, the treatment technology most compatible with potable reuse, infrastructure will already be in place for future indirect and direct potable reuse, and give the City better control of recycled water deliveries once a water reuse program is in place. The City will be ready to produce a drinking water quality resource for the community ahead of the need.

Cleaner water will be sent to local waterways and groundwater. The new advanced treatment technology will use 80 percent fewer chemicals and produce higher quality effluent, which means that higher quality water is discharged to San Luis Obispo Creek, the local groundwater basin, and more than 80 square miles of watershed. Cleaner water will flow to Avila Beach, a popular recreational spot, and habitat for steelhead and salmon will be improved with no chemical byproducts in the creek.

The project addresses another community priority: to reduce the facility’s impact on the local environment. Fewer chemicals needed for treatment will mean fewer truck deliveries, less traffic, and less carbon emissions. In addition, the plant will be able to produce more biogas, which may offset the facility’s energy demand.

Project benefits extend to community education. Engaging, retaining and educating future wastewater engineers, operators and lab technicians remains an ongoing industry challenge. Since 2007, the Cal Poly Sustainable Utilities Research and Education Group and the San Luis Obispo Water Resource and Recovery Facility have partnered to operate a 13,200 gallons per day pilot-scale wastewater treatment facility co-located with the existing facility. Students benefit from hands-on training and learn experience-based lessons from operators while developing and training future employees and project collaborators. Additionally, continued partnership with local K-12 schools has invited young students to learn about water treatment in the facility’s water quality lab.

As the City’s long-time project partner, WSC helped the City secure a $140 million SRF loan, $4 million in loan forgiveness and over $4 million in additional grants through the California Office of Emergency Services and Integrated Regional Water Management grant program. WSC has also provided strategic communications support for the project, referred to now as SLO Water+, including project branding, educational materials and videos, signage, website updates and ongoing communications.

The team is currently providing program management services for the project during construction, which is expected to be completed in 2023.

Learn more at

SLO Water+ Branding
2019 Groundbreaking Ceremony
2019 Groundbreaking Ceremony