The city of Adler is well known for its beaches along the Black Sea.
But on August 4, a sewage broke up on the Chkalovsky beach in Adler, creating a stinky mud geyser rushing out to the sea, and literally washing everything on its path, even holidaymakers.
As explained on the official website of the city, the black geyser was the consequence of an accident on the main drinking water conduit. Thedark color of the water is due to the washout of impurity of soil and earth from the walls of a storm collector.
In any cases, I would not call this dark and stinky water drinking water… But I have never been to Russia and thus cannot firmly corroborate my thoughts.