Each state applies a system of of designated uses and associated classifications to their waters. These classifications form the basis for applicable water quality standards, and vary by state. Refer to Chapter 2 of the EPA Water Quality Standards Handbook for more information on designation of uses.
These classifications are provided for informational purposes only and have not been reviewed or verified by the relevant states. Please refer to the state standards, linked at the bottom of this page, to ensure up to date information.
Please contact Richard Friesner with questions, comments, or updates.
Freshwater Classifications
Class AA:
Connecticut: Existing or proposed drinking water supplies; habitat for fish and other aquatic life and wildlife; recreation; and water supply for industry and agriculture.
Maine: Outstanding natural resources which should be preserved because of their ecological, social, scenic or recreational importance… Suitable for the designated uses of drinking water after disinfection, fishing, agriculture, recreation in and on the water, navigation and as habitat for fish and other aquatic life. The habitat must be characterized as free-flowing and natural.
New York: Water supply for drinking, culinary or food processing purposes; primary and secondary contact recreation; and fishing. The waters shall be suitable for fish, shellfish and wildlife propagation and survival. (NY also has class AA-special waters.)
Rhode Island: Public drinking water supply or tributary waters within a public drinking water supply watershed, primary and secondary contact recreational activities and for fish and wildlife habitat. These waters shall have excellent aesthetic value. Class AA waters used for public drinking water supply may be subject to restricted recreational use by State and local authorities.
Massachusetts, New Hampshire, and Vermont do not have a Class AA.
Class A:
CT: Habitat for fish and other aquatic life and wildlife; recreation; navigation; and industrial and agricultural water supply.
ME: Suitable for drinking water supply after treatment; fishing; agriculture; recreation in and on the water; industrial process and cooling water supply; hydroelectric power generation, except as prohibited; navigation; and as habitat for fish and other aquatic life. The habitat must be characterized as unimpaired.
MA: Sources of public water supply and their tributaries. Excellent habitat for fish, other aquatic life and wildlife, including for their reproduction, migration, growth and other critical functions, and for primary and secondary contact recreation, even if not allowed. These waters shall have excellent aesthetic value. These waters are protected as Outstanding Resource Waters.
NH: Waters of the highest quality, with no discharge of any sewage or wastes. The waters of this classification shall be considered as being potentially acceptable for water supply uses after adequate treatment.
NY: A source of water supply for drinking, culinary or food processing purposes; primary and secondary contact recreation; and fishing. The waters shall be suitable for fish , shellfish, and wildlife propagation and survival. (NY also has class A-special waters)
RI: Primary and secondary contact recreational activities and for fish and wildlife habitat. They shall be suitable for compatible industrial processes and cooling, hydropower, aquacultural uses, navigation, and irrigation and other agricultural uses. These waters shall have excellent aesthetic value.
VT Class A(1): Waters in a natural condition that have significant ecological value;
VT Class A(2): Waters that are suitable for a public water source with filtration and disinfection or other required treatment; character uniformly excellent.
Class B:
CT: Habitat for fish and other aquatic life and wildlife; recreation; navigation; and industrial and agricultural water supply. (Class B*: No wastewater discharges allowed other than those consistent with Class AA and A waters.)
ME: Suitable drinking water supply after treatment; fishing; agriculture; recreation in and on the water; industrial process and cooling water supply; hydroelectric power generation, except as prohibited; navigation; and as habitat for fish and other aquatic life. The habitat must be characterized as unimpaired.
MA: Habitat for fish, other aquatic life, and wildlife, including for their reproduction, migration, growth and other critical functions, and for primary and secondary contact recreation. Where designated…. they shall be suitable as a source of public water supply with appropriate treatment (“Treated Water Supply”). Class B waters shall be suitable for irrigation and other agricultural uses and for compatible industrial cooling and process uses.
NH: …Shall have no objectionable physical characteristics…There shall be no disposal of sewage or waste into said waters except those which have received adequate treatment to prevent the lowering of the biological, physical, chemical or bacteriological characteristics… nor shall such disposal of sewage or waste be inimical to aquatic life or to the maintenance of aquatic life in said receiving waters…The waters of this classification shall be considered as being acceptable for fishing, swimming and other recreational purposes and, after adequate treatment, for use as water supplies. All marine waters in NH are Class B.
NY: Primary and secondary contact recreation and fishing. These waters shall be suitable for fish, shellfish and wildlife propagation and survival.
RI: Fish and wildlife habitat and primary and secondary contact recreational activities. They shall be suitable for compatible industrial processes and cooling, hydropower, aquacultural uses, navigation, and irrigation and other agricultural uses. These waters shall have good aesthetic value. In Class B1 waters, primary contact recreational activities may be impacted due to pathogens from approved wastewater discharges. However all Class B criteria must be met.
VT Class B(1): Waters in which one or more uses are of demonstrably and consistently higher quality than Class B(2) waters;
VT Class B(2): Waters that are suitable for swimming and other primary contact recreation; irrigation and agricultural uses; aquatic biota and aquatic habitat; good aesthetic value; boating, fishing, and other recreational uses and suitable for public water source with filtration and disinfection or other required treatment.
Class C:
ME: …Suitable for drinking water supply after treatment; fishing; agriculture; recreation in and on the water; industrial process and cooling water supply; hydroelectric power generation, except as prohibited; navigation; and as a habitat for fish and other aquatic life.
MA: Habitat for fish, other aquatic life and wildlife, including for their reproduction, migration, growth and other critical functions, and for secondary contact recreation. These waters shall be suitable for the irrigation of crops used for consumption after cooking and for compatible industrial cooling and process uses. These waters shall have good aesthetic value.
NY: Fishing. These waters shall be suitable for fish, shellfish and wildlife propagation and survival. The water quality shall be suitable for primary and secondary contact recreation, although other factors may limit the use for these purposes.
RI: Secondary contact recreational activities and fish and wildlife habitat. They shall be suitable for compatible industrial processes and cooling, hydropower, aquacultural uses, navigation, and irrigation and other agricultural uses. These water shall have good aesthetic value.
CT, NH, and VT do not have a Class C.
Additional Freshwater Classifications:
Maine, Class GPA: Sole classification both of great ponds and of natural lakes and ponds less than 10 acres in size. Class GPA waters must be of such quality that they are suitable for the designated uses of drinking water after disinfection, recreation in and on the water, fishing, agriculture, industrial process and cooling water supply, hydroelectric power generation, navigation and as habitat for fish and other aquatic life. The habitat must be characterized as natural.
New York, Class D: The best usage of Class D waters is fishing. Due to such natural conditions as intermittency of flow, water conditions not conducive to propagation of game fishery, or stream bed conditions, the waters will not support fish propagation. These waters shall be suitable for fish, shellfish and wildlife survival. The water quality shall be suitable for primary and secondary contact recreation, although other factors may limit the use for these purposes.
New York, Class N: The best usages of Class N waters are the enjoyment of water in its natural condition and, where compatible, as a source of water for drinking or culinary purposes, bathing, fishing, fish propagation, and recreation. The waters shall be suitable for shellfish and wildlife propagation and survival and fish survival.
Vermont, all waters: In Vermont, designated uses are independently classified. This means that a waterbody may in the future be classified at different levels for individual uses, so long as the Class B2 minimum water quality conditions are maintained.
Saline Classifications
Vermont does not have saline classifications. All marine waters in New Hampshire are Class B.
Class SA:
Connecticut: Habitat for marine fish, other aquatic life and wildlife; shellfish harvesting for direct human consumption; recreation; industrial water supply; and navigation.
Maine: Outstanding natural resources which should be preserved because of their ecological, social, scenic, economic or recreational importance. Suitable for the designated uses of recreation in and on the water, fishing, aquaculture, propagation and harvesting of shellfish, navigation and as habitat for fish and other estuarine and marine life. The habitat must be characterized as free-flowing and natural.
Massachusetts: Excellent habitat for fish, other aquatic life and wildlife, including for their reproduction, migration, growth and other critical functions, and for primary and secondary contact recreation. In certain waters, excellent habitat for fish, other aquatic life and wildlife may include, but is not limited to, seagrass. Where designated for shellfishing, these waters shall be suitable for shellfish harvesting without depuration. These waters shall have excellent aesthetic value.
New York: Shellfishing for market purposes, primary and secondary contact recreation and fishing. These waters shall be suitable for fish, shellfish and wildlife propagation and survival.
Rhode Island: Shellfish harvesting for direct human consumption, primary and secondary contact recreational activities, and fish and wildlife habitat. Suitable for aquacultural uses, navigation and industrial cooling. These waters shall have good aesthetic value. Some Class SA waters contain Closed Safety Zones which are waters in the vicinity of an approved sanitary discharge which may be impacted in the event of complete failure of treatment and are therefore, currently prohibited to shellfishing. Although shellfishing use is restricted, all SA criteria must be met.
Class SB:
CT: Habitat for marine fish, other aquatic life and wildlife; commercial shellfish harvesting; recreation; industrial water supply; and navigation.
ME: …Suitable for the designated uses of recreation in and on the water, fishing, aquaculture, propagation and harvesting of shellfish, industrial process and cooling water supply, hydroelectric power generation, navigation and as habitat for fish and other estuarine and marine life. The habitat must be characterized as unimpaired.
MA: habitat for fish, other aquatic life and wildlife, including for their reproduction, migration, growth and other critical functions, and for primary and secondary contact recreation. In certain waters, habitat for fish, other aquatic life and wildlife may include, but is not limited to, seagrass. Where designated for shellfishing, these waters shall be suitable for shellfish harvesting with depuration (Restricted and Conditionally Restricted Shellfish Areas). These waters shall have consistently good aesthetic value.
NY: Primary and secondary contact recreation and fishing. These waters shall be suitable for fish, shellfish and wildlife propagation and survival.
RI: Primary and secondary contact recreational activities; shellfish harvesting for controlled relay and depuration; and fish and wildlife habitat. They shall be suitable for aquacultural uses (other than shellfish for direct human consumption), navigation, and industrial cooling. These waters shall have good aesthetic value. In Class SB1 waters, primary contact recreational activities may be impacted due to pathogens from approved wastewater discharges. However, all Class SB criteria must be met.
Class SC:
ME: …Suitable for recreation in and on the water, fishing, aquaculture, propagation and restricted harvesting of shellfish, industrial process and cooling water supply, hydroelectric power generation, navigation and as a habitat for fish and other estuarine and marine life.
MA: Habitat for fish, other aquatic life and wildlife, including for their reproduction, migration, growth and other critical functions, and for secondary contact recreation. They shall also be suitable for certain industrial cooling and process uses. These waters shall have good aesthetic value.
NY: Fishing. These waters shall be suitable for fish, shellfish and wildlife propagation and survival. The water quality shall be suitable for primary and secondary contact recreation, although other factors may limit the use for these purposes.
RI: Secondary contact recreational activities, and fish and wildlife habitat. They shall be suitable for aquacultural uses, navigation, and industrial cooling. These waters shall have good aesthetic value.
CT does not have a class SC.
Additional Saline Classifications:
NY, Class SD: Fishing. These waters shall be suitable for fish, shellfish and wildlife survival. In addition, the water quality shall be suitable for primary and secondary contact recreation, although other factors may limit the use for these purposes. This classification may be given to those waters that, because of natural or man-made conditions, cannot meet the requirements for fish propagation.
NY, Class I: Secondary contact recreation and fishing. These waters shall be suitable for fish, shellfish, and wildlife propagation and survival. In addition, the water quality shall be suitable for primary contact recreation, although other factors may limit the use for this purpose.
NH, Class B: All marine waters in NH are class B: Shall have no objectionable physical characteristics…There shall be no disposal of sewage or waste into said waters except those which have received adequate treatment to prevent the lowering of the biological, physical, chemical or bacteriological characteristics… nor shall such disposal of sewage or waste be inimical to aquatic life or to the maintenance of aquatic life in said receiving waters…The waters of this classification shall be considered as being acceptable for fishing, swimming and other recreational purposes and, after adequate treatment, for use as water supplies.
State Statutes and Sources
Connecticut: Department of Energy and Environmental Protection, Title 22a-426, Section 4
Massachusetts: Division of Water Pollution Control, Massachusetts Surface Water Quality Standards, 314 CMR 4.05
New Hampshire: Department of Environmental Services, Classification of Waters, Title L, Chapter 485-A, Section 8
Rhode Island: Department of Environmental Management, Water Quality Regulations, 250- RICR-150-05-1
Vermont: Vermont Department of Environmental Conservation, Title 10, Ch 47(1), Sec. 1252