This summer the Chicago Park District is piloting a new program to rapidly detect bacterial contamination at five of the city’s beaches. The pilot program will cover Calumet, Rainbow, South Shore, 63rd Street, and Montrose beaches.

Through a partnership with the University of Illinois at Chicago, the parks department will know whether beaches are safe for recreation within a few hours rather than the next day. Traditionally, the parks district has collected samples at the city’s beaches in the morning and analyzed the samples for E. coli. With a new method that counts DNA fragments, however, staff will have results by early afternoon the same day.

If samples are found to contain more than 235 colony forming units per 100 milliliters of water – based on U.S. Environmental Protection Agency Recreational Water Quality Criteria – beach managers will issue swim advisories using a flag notification system and online display.