One way for New York City to protect its drinking water supply is to purchase undeveloped lands throughout the watershed. By protecting streams and wetlands, keeping large areas forested, and keeping sensitive lands from being developed, good water quality can more adequately be ensured. The NYC Department of Environmental Protection has divided up the watershed into land acquisition priority areas, with areas designated ‘1A’ having the highest protection priority, and areas designated ‘4’ having the least protection priority. Priority area designations are based on travel time to intake valves, proximity to reservoirs and primary tributary streams, presence of wetlands, steep slopes, etc. The purchase of watershed lands by the City is on a willing buyer-willing seller basis, and the City pays full fair market value as determined by independent appraisers.