Sure.....we already do it here
"" A third successive year of California's worst
drought in a century has the Golden State's
reservoirs at record lows. Agriculture has
been affected, hitting the local economy,
while some small communities risk running
out of water.
But business is booming in California's
Orange County Water District (OCWD),
through a pioneering wastewater treatment
facility that recycles used water -- or sewage
-- and returns it to the drinking supply. The
plant is expanding production from 70 to 100
million gallons per day, enough for 850,000
people, around one-third of the county
population. As the OWCD output is mixed
with the main groundwater supply it reaches
over 70% of residents.""
Link.
And Ive drank untold gallons of river water......no telling WHAT the hell was in there lol