After 10 months of negotiations, the planned merger between the Coastal Health Alliance and West County Health Centers has been called off. Steven Siegel, the health alliance’s C.E.O., made the surprise announcement outside the clinic last week during an annual taco truck celebration of national health center week, citing a “difference in philosophy.”

In May, the alliance’s board voted unanimously to pursue the merger, which a consultant had described as a remarkable fit. The merger had been intended to help the alliance’s nonprofit clinics in Point Reyes Station, Bolinas and Stinson Beach grow their staff. 

Now, “Plan B is to bring the alliance into the future on our own, making any necessary adjustments to staff that we have been holding back on while the merger was on the table,” Mr. Siegel said.

Larger organizations like West County Health Centers, which has eight clinics and over 235 employees, have designated staff for every job, he said. But the alliance, with just 50 staffers, often has employees multitasking. 

With two new physician assistants coming on in September, Mr. Siegel said the next hires will likely be another physician, an accounting manager and someone for the human resources department. He was not concerned about the financial side of making these hires, saying the clinic was “in great shape.”

Representatives from West County Health Centers were not available for comment before press time, but a joint statement released Monday said the two health organizations “would not continue to pursue a legal affiliation at this time.” 

The release said that “while we found that our two organizations have many commonalities, we learned through our exploration there were issues and differences that would not serve each organization’s interest in maintaining and enhancing high quality health services in our respective communities.” 

The Coastal Health Alliance began in 1981 when local residents encouraged Dr. Michael Witte to open a bilingual clinic in Point Reyes Station to serve low-income community members. 

A comprehensive needs assessment conducted in 2010 said an increase in second homes was leading to a shrinking population and changes in demographics. The report recommended the nonprofit fuse with a larger health organization in order to maintain a strong base of patients.

Mr. Siegel said that although patient counts are slightly down overall since 2010, there has been an increase in the percentage of patients from West Marin—65 percent of all patients are from the area—and an upward trend in the number of visits per patient.