A blockage in a sewer line in Adams Morgan caused an overflow of about 1,200 gallons of untreated waste into Rock Creek Wednesday.
"It was untreated, compared to the spills that we sometimes have that of combined sewage, which is diluted with storm water," said John Lisle of DC Water.
DC Water advised the public to avoid the water in Rock Creek from below Calvert Street Bridge south of the National Zoo to the mouth of the creek for the next 72 hours. The National Park Service warned the public not to fish in the creek and advised people who use the creek to sanitize equipment that has been in the water south of the sewage spill.
"Anything that comes in contact -- whether it's a human or a pet or fishing equipment or anything else that might have come in contact with the water -- it's probably a good idea to wash it off, sanitize it as much as you can, but just as a precaution," Lisle said.
DC Water put a bypass in place Thursday morning to direct the sewage around the blockage.
Crews are working to clear the blockage and repair the 24-inch cast iron line, which dates to 1885. The work should be finished by early next week.