As of Sunday afternoon, Contra Costa County had reported 175 confirmed novel coronavirus cases and three deaths from COVID-19, according to the Contra Costa Health Services website.
Those numbers are up from 151 cases and two deaths reported at 9:30 a.m. Saturday.
It wasn't immediately known Saturday night the degree to which increased testing played a part in the higher number of cases.
Two of the three reported deaths have come since Friday morning.
Contra Costa County health officials have announced plans to prepare parts of at least two facilities -- the former Los Medanos Community Hospital in Pittsburg and Alhambra High School in Martinez -- for treatment of some county patients as a surge of COVID-19 patients is expected.
Data reported by other counties' health officials, as of Sunday afternoon, included Alameda County (including city of Berkeley): 270 cases, 7 deaths.
Marin County: 74 cases, 1 death.
Monterey County: 36 cases, 1 death.
Napa County: 10 cases.
San Francisco County: 340 cases, 5 deaths.
San Mateo County: 277 cases, 6 deaths.
Santa Clara County: 646 cases, 25 deaths.
Santa Cruz County: 44 cases, 1 death.
Solano County: 34 cases.
Sonoma County: 58 cases, 1 death.
Statewide: 5,827 cases, 124 deaths.