New York State Banner
D E C banner
D E C banner

Water Quality Standards and Classifications

This program is responsible for setting New York State ambient water quality standards and guidance values for surface waters and groundwaters throughout the State. The program is also responsible for the classification of surface waters for their best usage (best use), and for regulations restricting phosphorus and nitrilotriacetic acid (NTA) in household cleansing products. The water quality standards program is a state program with federal (U.S. EPA) oversight. New York's longstanding water quality standards program predates the federal Clean Water Act and protects both surface waters and groundwaters.

Information regarding the New York State Water Quality Standards Program can be found in state regulation, specifically New York Codes, Rules and Regulations Title 6 (6 NYCRR) and guidance documents found in the Division of Water Technical and Operational Guidance Series (TOGS).

DEC standards are both narrative (e.g., "none in amounts that will impair ...") and numeric (e.g., "0.001 µg/L") and are promulgated in regulation 6 NYCRR Part 703. Numeric guidance values are derived in the absence of a standard, and compiled in the Division of Water TOGS 1.1.1 and its Addenda. Ambient standards and guidance values apply to the waterbodies and are supported by technical documents, called "Fact Sheets" that are available from this program. Contact Scott Stoner for more information.

All waters in New York State are assigned a letter classification that denotes their best uses. Letter classes such as A, B, C, and D are assigned to fresh surface waters, and SA, SB, SC, I, and SD to saline (marine) surface waters. Best uses include: source of drinking water, swimming, boating, fishing, and shellfishing. The letter classifications and their best uses are described in regulation 6 NYCRR Part 701. The classification of individual bodies of surface water is in regulation 6 NYCRR Chapter X (Parts 800 - 941), and on the Environmental Resource Mapper. Contact Scott Stoner for more information.

Surface waters of the State are reclassified through the formal rule making process. Requests for reclassification can be made by submitting a completed Reclassification Information Form (pdf, 45kb) to the Department (ATTN: Scott Stoner) at the address on the form.

The best use of Class GA groundwater (all fresh groundwater in New York State is Class GA) and Class A, A-Special, AA, and AA-Special surface waters is a source of potable water supply. Standards and guidance values of the Health (Water Source) Type are established for these waters to protect this use. Separate standards for drinking water are promulgated by the New York State Department of Health (NYS DOH).

Standards and guidance values of other Types, including Health (Fish Consumption), Aquatic (Chronic), Aquatic (Acute), Wildlife, and Aesthetic are also established. Further information is provided in the Introduction to TOGS 1.1.1.

Water quality standards and standard-setting procedures are in 6 NYCRR Chapter X, Parts 700-706. Household cleansing products regulations are in 6 NYCRR, Part 659.

The program also maintains three Technical and Operational Guidance Series (TOGS) providing information on deriving water quality guidance values for human and wildlife health,as well as bioaccumulation factors and site-specific standards:

  • TOGS 1.1.3 - Procedures for site-specific standards and guidance value.
  • TOGS 1.1.4 - Procedures for deriving bioaccumulation factors.
  • TOGS 1.1.5 - Procedures for deriving standards and guidance values for wildlife.

For further information, contact Scott Stoner.