A ritzy Arizona enclave is facing water cuts, and the most divisive idea to offset them begins with millions of gallons of sewage. Call it affluent effluent.

The plan — which involves rigorously treating and purifying wastewater, then routing it straight to residential taps — has long been seen as critical for the future of Scottsdale, a city heavily reliant on the dwindling flow of the Colorado River.

But in recent months, Scottsdale’s wastewater recycling program has been sucked into a bitter political dispute, and its fate could hinge on the outcome of the city’s elections Tuesday.

The Scottsdale City Council, on which two seats are up for grabs, is nominally nonpartisan, but this year’s race may change the balance of power on water issues. Two candidates, both running on a right-wing platform, deride wastewater recycling as an unproven experiment.…