We begin with the text of §1311(b)(1)(C), which, as noted, requires a permit to contain, in addition to “effluent limitations,” “any more stringent limitation” that is “necessary to meet” certain “water quality standards” that are imposed under state law “or any other federal law or regulation”; and “any more stringent limitation” that is “required to implement any applicable water quality standard established pursuant to this chapter.” (Emphasis added.) All the italicized terms in the preceding sentence suggest that the most natural reading of §1311(b)(1)(C) is that it authorizes the EPA to set rules that a permittee must follow in order to achieve a desired result, namely, a certain degree of water quality.
We start with the term “limitation.” As used in the relevant context, a limitation is a “restriction or restraint imposed from without (as by law[)].” Webster’s Third New International Dictionary 1312 (1976) (emphasis added). A provision that tells a permittee that it must do certain specific things plainly qualifies as a limitation. Such a provision imposes a restriction “from without.” But when a provision simply tells a permittee that a particular end result must be achieved and that it is up to the permittee to figure out what it should do, the direct source of restriction or restraint is the plan that the permittee imposes on itself for the purpose of avoiding future liability. In other words, the direct source of the restriction comes from within, not “from without.”
We do not dispute that the term “limitation” is sometimes used in a looser sense, but our task is to ascertain what the term means in the specific context in question. And here, our interpretation of the meaning of the term “limitation” in §1311(b)(1)(C) must take into account the way in which the term is used in the two preceding statutory subsections,§§1311(b)(1)(A) and (B). In both those provisions, the “limitations” are imposed directly by the EPA, and it is therefore natural to presume that the term has a similar meaning in §1311(b)(1)(C). See, e.g., McDonnell v. United States,579 U. S. 550, 568–569 (2016); Yates v. United States, 574U. S. 528, 544 (2015) (plurality opinion); A. Scalia & B. Garner, Reading Law 195–198 (2012). So the use of the term “limitation” in §§1311(b)(1)(A) and (B) provides an opening clue that the EPA’s interpretation of §1311(b)(1)(C) may be wrong.
The terms “implement” and “meet” point in the same direction. The implementation of an objective generally refers to the taking of actions that are designed “to give practical effect to and ensure of actual fulfillment by concrete measures.” Webster’s Third New International Dictionary, at 1134. Section 1311(b)(1)(C) tells the EPA to impose requirements to “implement” water quality standards—that is, to “ensure” “by concrete measures” that they are “actual[ly]” “fulfill[ed].” Simply telling a permittee to ensure that the end result is reached is not a “concrete plan” for achieving the desired result. Such a directive simply states the desired result; it does not implement that result.
Section 1311(b)(1)(C)’s other directive—that the EPA impose limitations that are “necessary to meet” certain water quality standards–is similar. The verb to “meet,” in the sense operative here, means “to comply with; fulfill; satisfy ”or “to come into conformity with.” Random House Unabridged Dictionary 1195 (2d ed. 1987). Thus, a limitation that is “necessary to meet” an objective is most naturally understood to mean a provision that sets out actions that must be taken to achieve the objective.
