“There should not be” any deterioration of water quality in the Washington area from the sewage, McIntire said. Similar spills have occurred in the past without ill effects, he said. – Washington Post
The Maryland Department of the Environment told the Post that they expected dilution to prevent adverse effects to drinking water. However no mention was made on the effects of recreationists such as kayakers who are likely to have direct contact with untreated water.
Stuart A. Freudberg, director of environmental programs for the Metropolitan Washington Council of Governments, estimated that even in the Hagerstown area, the partially treated sewage would make up less than 1 percent of river flow. – Washington Post
The sewage release was caused by the introduction of an unidentified chemical to the sewage facility. This strange chemical killed at least 60% of the good bacteria used to treat the sewage.