The relevance of beer with regard to water conservation and safe consumption is _not_ because the alcohol sterilizes the fluid. It's because successfully brewed and unfiltered beer forms a relatively stable ecosystem of unproblematic yeasts and lactic acid bacteria which prevent other unsafe micro organisms to take over and multiply. The hop is actually contributing to chemical conservation, though.
Hops are antibiotic and antifungal in nature. That, combined with their mild flavor (compared to things like wormwood), is why they are synonymous with beer production today.