The New York City Department of Environmental Protection (DEP) protects public health and the environment by supplying clean drinking water, collecting and treating wastewater, and reducing air, noise, and hazardous substances pollution. DEP is an agency of nearly 6,000 employees that manage and conserve the City's water supply; distribute more than one billion gallons of clean drinking water each day to nine million New Yorkers and collect wastewater through a vast underground network of pipes, regulators, and pumping stations; and treat the 1.2 billion gallons of wastewater that New Yorkers produce each day in a way that protects the quality of New York Harbor. To achieve these mandates, DEP oversees one of the largest capital construction programs in the region. As the City agency responsible for New York City's environment, DEP also regulates air quality, hazardous waste, and critical quality of life issues, including noise.