As of 10/25/20202:
CDC GUIDELINES - People who have tested positive for COVID-19 do not need to quarantine or get tested again for up to 3 months as long as they do not develop symptoms again within that 3 months. People who develop symptoms again within 3 months of their first bout of COVID-19 may need to be tested again if there is no other cause identified for their symptoms.
Length of quarantine for all others —if you have been exposed to someone who has tested positive—CDC GUIDELINES—You should stay home for 14 days after your last contact with a person who has COVID-19.
(FYI-Paperwork from testing even if it is negative at this time is showing a return to school/work date of 14 days from last positive exposure date.)