Both of the assumptions in this question are somewhat misleading -- alcohol existed in the pre-Columbian Americas, and alcohol was never used to replace water. You may be interested in these previous questions:

"How did people (esp. European townsmen) get fresh water in the Middle Ages? - answer by /u/idjet

"You often hear anecdotally that 'Alcohol was so prevalent in the Middle Ages because it was safer than water'" - answer by /u/eternalkerri

"How did the Native Americans (including those in South America, such as the Aztecs) purify their drinking water?" - answer by /u/RioAbajo

"Did Native Americans ever produce alcohol?" - answer by /u/Pachacamac

"What kinds of alcoholic beverages did the Native Americans/First Nations consume?" - answer by /u/Mictlantecuhtli