San Luis Obispo County Public Health officials say 10,000 gallons of sewage was released in Morro Bay after a main break Monday.
No cause has been given for the break at this time, but the affected area of Coral Avenue is near a sewage lift station.
Health officials say after the break the sewage was contained to a retention basin between Highway 1 and Coral Avenue next to the release site.
Barriers and signs have been placed around the site to alert the public of the contamination.
The city is advising the public to avoid the contaminated area.