The spill poses little heath risk as the minor amount of sewage was diluted by 34,410 gallons of drinking water, said Michael Scahill, Metropolitan Wastewater Department public information officer.
Leaked water from the 50-year-old concrete pipe flowed to a manhole 50-feet away, which accesses belowground sewer lines.
"There was so much water coming out of this water main that it literally came in through the joints of the manhole," Scahill said.
The water-sewage mixture spilled into the street and traveled to a storm drain, which carried it to the San Diego River. The water line was shut off three hours later at 1:30 a.m. Both lines have since been repaired.
Warnings, not closures, were subsequently issued for Dog Beach. Rains in the area are not likely to aggravate another sewage spill from that location, but do carry street runoff into the ocean through storm drains, which could result in further beach warnings.