REGISTER STAFF Coronavirus testing in Napa County is perhaps the most available it has ever been, Napa Countyâs website shows. Testing turn around times at any one site often depends on regional levels of demand; high demand for testing across the Bay Area has previously skewed wait times, though most test sites in the county tell residents to expect a result within two to five business days. This list does not claim to be comprehensive and may be updated as the availability of testing changes. Check back for updates. OptumServe Drive Through, Napa Valley Expo, 575 Third St., Napa Who qualifies for a test: Asymptomatic or symptomatic; minors must be accompanied by a parent or guardian.