Water Treatment
Shaft 22 water is fluoridated and chlorinated by New York City at Kensico Reservoir. Caustic soda is added at Shaft 22 to increase the pH of the water. The Water Works provides additional chlorination at its Larchmont Station and adds a blended poly-orthophosphate as a corrosion inhibitor at that point.

Rye Lake water is fluoridated, chlorinated and provided with a blended poly-orthophosphate at the source, with pH adjustment using caustic soda after the water passes through the Purchase Tanks on Purchase Street in the Town of Harrison.