You can use the Waterbody Advisory System when planning recreational activities on New York City waterways other than beaches. It is based on water quality models and real-time rainfall data. The Waterbody Advisory System (beta version):
For beach information, visit NYC Beach Water Quality. Learn more about ways we are improving water quality in New York City.
If you detect any problems with the Waterbody Advisory System, please email ltcp@dep.nyc.gov. You can also sign up for waterbody alerts at NotifyNYC.