He said crowds at the American River near Sacramento recently made it look like "spring break."
"We're not minimizing mixing. It throws shivers up my spine," said Newsom. "Here we are making all this progress, and it can be done away."
WATCH: Gov. Gavin Newsom discusses state's task force focusing on jobs, economic recovery
Gov. Newsom reported 11,645 new COVID-19 cases over the past 24 hours, but that number includes a lot of backlogged cases that haven't yet been reported. A data glitch on July 25 left 295,000 health records - many of them COVID-19 tests - unprocessed. The glitch led to an underreporting of new coronavirus cases.
He said the state's county watch list has been frozen as the state straightens out the inaccurate COVID-19 data. The governor said the watch list would be unfrozen at some point this week, once the backlog was fully cleared.
RELATED: CA could see another surge in confirmed COVID-19 cases following fix to backlog of 300K records, officials say
ICU hospitalization numbers continue to trend down.
The beginning of Newsom's press conference was focused on the long path toward economic recovery.
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