In order to protect the health of beachgoers better, the Chicago Park District has expanded its use of a rapid testing method to evaluate water safety. This method — used at nine beaches last summer and expanded to all 20 beaches for the swimming season that started the Friday of Memorial Day weekend — uses DNA testing of Enterococci. It gives results in three to four hours instead of 18 to 24 hours with previous testing methods. This allows the Park District to issue its Green / Yellow / Red flags — corresponding to No Restrictions / Swim Advisory / Swim Ban — from lab results instead of predictions, verified with lab results the next day, as was necessary with previous technology. The test results are available on the City of Chicago Data Portal.
The City, Park District, and volunteer Data Scientists organized out of Chi Hack Night are working on an experimental technique to predict water safety at all beaches, based on DNA testing from a subset of beaches. This work is very early but there are hopes of being able to use it to manage beaches more economically in future summers. Preliminary data and a map can also be found on the Data Portal.