Government agencies are all primarily concerned with keeping the New York City water supply system safe for everyone as well as compiling with the SWTR. In order to maintain the water quality, government agencies can either ensure the quality of unfiltered water to satisfy the provisions of the SWTR for unfiltered water, or filter the water if the quality drops. The cost of constructing a filtration facility would be $6-8 billion and would cost $500 million annually to operate. This is extremely costly, and government agencies would be in favor of the most cost-effective solution, which would to continue to allow water to flow into New York City unfiltered. The City regularly issues reports on the DEP’s source water protection programs established to maintain the Filtration Determination Avoidance for the Catskills and Delaware portion of the NYC water supply. The Filtration Avoidance Annual Report for 2011 and well as other reports show why it is unnecessary for the NYC water supply to be filtered.
New York City first applied a waiver from the filtration requirements of the Surface Water Treatment rule in 1991 for the Catskill/Delaware system. Since then, the DEP has spent more the $1.5 billion to maintain the quality of the source waters of the Catskills and Delaware watersheds. The DEP’s source water protection program is based on research done by DEP scientists about existing and potential sources of water contamination. SWTR monitoring includes monitoring raw water for fecal coliform concentrations, turbidity, disinfection values, entry point monitoring for chlorine residuals, distribution monitoring for chlorine residuals, coliform bacteria levels, trihalomethanes, and haloaceitc acids. The percentage of positive raw water fecal samples was below the maximum percentage allowed by the SWTR. During 2011, there was only one occasion when the raw water turbidity level was greater than 5 NTU, at 5.1 NTU, but the regulatory limit is 5.4 NTU, so the water was still safe. All chlorine residuals were detectable in the 15,020 samples collected, and all of the other monitoring samples complied with the standard set by the SWTR. Since the City is able to meet the Filtration Avoidance criteria and has also laid out a plan for the DEP’s proposed source water protection program activities for 2012 to 2017 as well as a Long-Term Watershed Protection Plan, it is unnecessary for New York City to filter it’s water. It is much more cost-effective to leave the water unfiltered.
Source:
New York City Department of Environmental Protection. March 2012. Filtration Avoidance Annual Report for the Period January 1 through December 31, 2011. Web. 2 Dec. 2012. <http://www.nyc.gov/html/dep/pdf/2011_bws_fad_annual.pdf>.
