A newly opened public pool in north Minneapolis has the distinction of being the nation's first to be naturally filtered and free of chemicals.
The Webber Natural Swimming Pool filters its water through a series of biological filters into a nearby basin, where gravel and thousands of aquatic plants cleanse the water before it's pumped back into the pool.
The system cycles through all 500,000 gallons of the pool's capacity every 12 hours.
Officials cautioned, however, that the system is more sensitive than chemically treated pools and requires cooperation from the public to stay open. Outside food or beverages, glass items, tobacco and pets are prohibited, and swimwear must be comprised of nylon, silicone, latex, Lycra and polyesters.
The project — at four years in the making and totaling $6 million in funding — was both overdue and over budget, but it is now open on Fridays, Saturdays and Sundays at no cost to swimmers.
Parks officials speculated that Webber Park would be the first of many chemical-free pool projects in the U.S.