Importance of Existing Uses

Existing and Designated Uses

“Existing uses are those uses actually attained in the water body on or after November 28, 1975, whether or not they are included in the water quality standards.”

“Designated uses are those uses specified in water quality standards for each water body or segment whether or not they are being attained.”

(40CFR131.3(e-f))

Protection of Existing Uses

CWA regulations at 40 CFR131.10(h) state “States may not remove designated uses if...they are existing uses, as defined in Section 131.3, unless a use requiring more stringent criteria is added.”

In addition, the antidegradation policy states flatly that

“[e]xisting instream water uses and the level of water quality necessary to protect the existing uses shall be maintained and protected.”

(40CFR131.12(a)(1))

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