Expanded testing found no lasting harm to the Potomac River from January’s collapse of the Potomac Interceptor sewer line, DC Water said.
“These results are reassuring. They reconfirm what earlier testing indicated — that the river has returned to normal,” Interim General Manager Matthew T. Brown said.
Crews sampled the river every day for more than six months, at as many as 10 spots upstream and downstream of the overflow, and tested for E. coli. Bacteria levels had already returned to the river’s normal range, and health advisories were lifted. In August, DC Water added tests for oxygen, nutrients, and metals, collected five times at six locations in Maryland. Those results were also in the normal range.
