CDC guidelines: https://www.cdc.gov/ncird/whats-new/updated-respiratory-virus-guidance.html
California is explicit in its guidance and CDC appears to have the same goal:
"For asymptomatic confirmed cases, there is no infectious period for the purpose of isolation or exclusion. If symptoms develop, the criteria above will apply." https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/COVID-19/Order-of-the-State-Public-Health-Officer-Beyond-Blueprint.aspx