New York City: To filter or not to filter?

Under the Surface Water Treatment Rule (SWTR), New York City is required to filter its Catskill-Delaware water supply unless it can meet the criteria to avoid filtration. A panel was appointed by the US Environmental Protection Agency (USEPA) in the summer of 1992 to advise the agency about whether to grant New York City permission to avoid filtration. The panel concluded that although the water quality criteria were met marginally, the requirements for watershed control were not met. The panel also concluded that the city would probably not be able to meet the water quality requirements of an enhanced SWTR, which would likely include, among other additional requirements, measures to control Cryptosporidium. Despite the panel's recommendation for filtration, USEPA granted New York City an avoidance of filtration first through 1993, then through 1996,1999, and 2002. Although the city has negotiated a very useful watershed agreement with the upstate communities in the Catskill-Delaware watershed, the issues remain the same. This article assesses the issues involved.