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Assessing water quality in NY

New York State has more than 87,000 miles of rivers and streams, nearly 7,900 lakes and ponds, nearly 600 miles of Great Lakes coastline, over 1,530 square miles of estuaries, and 120 miles of Atlantic Ocean coastline. The Division of Water (DOW) annually uses the information gathered by its monitoring programs to assess the health of these waterbodies and the watersheds draining to them.

Watershed-wide water quality reports such as the Waterbody Inventory/Priority Waterbodies List, Section 305(b) Water Quality Report, and Section 303(d) List of Impaired/TMDL Waters are the result of the annual health assessments and help the DOW prioritize protection and restoration activities. To produce these reports, the DOW collaborates with DEC regional offices, other DEC divisions, and local, state and federal governments. Public input is incorporated as well.

"Best use" classifications

New York waterbodies are assigned a "best use" classification. Best use classifications are:

  • Class AA and A -- drinking water
  • Class B -- public swimming and contact recreation activities
  • Class C -- fishing and non-contact activities
  • Class D -- does not support any of the uses listed above (this classification is rarely used)

Waterbodies with AA, A, B and C classifications may also have "T" or "TS" classifications, meaning they support trout populations or trout spawning.

Best use classifications help the DOW develop water quality standards that specify a maximum amount of a pollutant that can be present in a waterbody and still allow it to achieve its best use classification. Monitoring information and assessment reports are the basis for determining if individual waterbodies are meeting their best use classifications and if more or different protection or restoration efforts are needed for a particular waterbody or even an entire watershed.

  • Contact for this Page
  • Division of Water
    625 Broadway
    Albany, NY
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