The California Department of Public Health requires congregate facilities to report all confirmed and probable COVID-19 cases (residents and staff) to their local health department. This web page has information about how to report to Placer County Public Health department. https://www.placer.ca.gov/coronavirus/healthcare Select "Congregate Facilities Reporting" tab.

Such settings include child care centers, residential homes for elders, skilled nursing facilities, etc.

Additional info here: https://www.placer.ca.gov/7068/Businesses