DayZ field wiki · Survive
Rivers
Moving water is still water
Short answer
A river looks cleaner than a pond. The sickness does not care about your poetry.
Also: stream water · lake · fill from river
How it works
Ponds, lakes, rivers — untreated they are a delayed death. Wells and pumps are the landmark that matters.
What to do
Fill at a well. Boil or tablet if you had to take the river.
Don't
Don't sip the stream because it looks pretty on stream.