San Mateo County backs Burlingame site for Horizon treatment facility

Board President Noelia Corzo cast the opposing vote, sharing her concern that the indemnification agreement — which was an amendment proposed by Supervisor Ray Mueller — would set an unsustainable precedent. The agreement would aim to limit Burlingame’s liability and keep it with the county.

With the supervisors’ vote, Horizon Treatment Services may now present the Burlingame site as a viable option to the state for a proposed 69-bed behavioral health treatment facility that brings sobering, detox and residential care under one roof. 

The state’s Department of Health Care Services previously awarded the nonprofit a $25 million grant in October 2025 to establish a facility in San Mateo County, initially tied to a site identified at 101 N. El Camino Real in San Mateo. The nonprofit is hoping to get the state’s OK to move the proposed facility to the Mahler Road site in Burlingame, instead.  

The site change came after residents near the San Mateo location raised concern over the facility being housed nearby. The county acted quickly, after already approving the San Mateo location, and looked at a site further away from residences in Burlingame. The Mahler Road site is in a light industrial area off Highway 101.

“The state has expressed openness in considering a transfer, but they want to know all the details,” Horizon Treatment Services CEO Jaime Campos said at the board meeting Tuesday. “They’re betting on the risk profile of the project.” 

The Board of Supervisors direction to county staff to begin drafting a lease agreement with Horizon lets the nonprofit “establish site control” of the Burlingame property which would provide a substantive bargaining point for the site transfer, Campos said. 

If the state believes the Burlingame site does not work, the state indicated it would want the Board of Supervisors to reaffirm its commitment to the formerly agreed upon San Mateo site, Campos said. 

“The state has the final authority as it relates to approving the transfer plan,” Campos said. “If for whatever reason it is not approved, we feel like we’ve engaged the [San Mateo] site community … and these engagement efforts, they continue to this very day.” 

Reflecting on months of controversy and back and forth regarding the proposed treatment facility, Campos said the ordeal could be simplified if invested parties thought about the individuals who would receive treatment and the impact of these services on their families. 

One mother, who lost her son to drug overdose, shared with Horizon staff her “great loss, great sadness and fearless support of the mission which we’re charged with making good on,” Campos said. 

“It is this story that calls upon us all to put our differences aside regarding what the picture perfect location might look like and just truly focus on the task at hand,” Campos said. 

Public commenters at the board meeting shared their hope for the county to “come back together” after months of tensely debated meetings. 

“I believe it’s an amazing investment for the county and holds the health for all our residents and the future of our county in high regard,” Alicia Isero said, refocusing the conversation on getting a treatment facility available to county residents as soon as possible.

Supervisor Lisa Gauthier spoke to a similar sentiment, expressing her frustration over how the placement of this treatment center has transpired. 

“I would love for us to get to a place where we can work collaboratively and realize we need services in every city because we have residents in every city,” Gauthier said. “This is an opportunity to move forward.”

The supervisors’ vote was taken the morning after the site proposal was presented to the Burlingame City Council. Councilmembers largely acknowledged the limited authority they have in the matter, considering the site is county-owned land, but still shared their concerns about risk to the city. 

At the Burlingame meeting, Campos reiterated Horizon’s commitment to being a good neighbor.

Next steps 

The supervisors’ approval directs staff to negotiate a long-term lease with the possibility of purchase, so Horizon can go to the state and present the nearly finalized option. A determination on the Burlingame site’s feasibility was due to the state’s Department of Health Care Services by Wednesday. 

Should the state confirm the site shift, the construction timeline is estimated to take an additional four to six months beyond what was previously anticipated at the San Mateo location, Campos said. 

“It’s doable; it comes at the expense of time,” Campos said. 

Callagy said the county will open an interim sobering station on the property in the coming months while the Horizon facility is being built, “so we can serve the community better, get those folks who are brought in by law enforcement treatment options that they need.” 

Whether the site shift is ultimately approved is up to the state, Campos emphasized. And regardless of where the facility is ultimately placed, monthly meetings will be held with Callagy, county staff and interested parties of the surrounding areas of the treatment facility.