FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

UPPER MISSOURI WATERKEEPER,

Plaintiff-Appellee,

v.

U.S. ENVIRONMENTAL PROTECTION 

AGENCY; MICHAEL REGAN,

*

 

Administrator, United States 

Environmental Protection Agency,

Defendants,

TREASURE STATE RESOURCES 

ASSOCIATION OF MONTANA; STATE 

OF MONTANA DEPARTMENT OF 

ENVIRONMENTAL QUALITY,

Intervenor-Defendants,

and

NATIONAL ASSOCIATION OF CLEAN 

WATER AGENCIES; THE MONTANA 

LEAGUE OF CITIES AND TOWNS,

Intervenor-Defendants-Appellants.

No. 19-35898

D.C. No.

4:16-cv-00052-

BMM

* Michael Regan has been automatically substituted for former 

Administrator Andrew Wheeler. Fed. R. App. P. 43(c)(2).
2 UPPER MISSOURI WATERKEEPER V. USEPA

UPPER MISSOURI WATERKEEPER,

Plaintiff-Appellee,

v.

U.S. ENVIRONMENTAL PROTECTION 

AGENCY; MICHAEL REGAN, 

Administrator, United States 

Environmental Protection Agency,

Defendants,

NATIONAL ASSOCIATION OF CLEAN 

WATER AGENCIES; THE MONTANA 

LEAGUE OF CITIES AND TOWNS;

STATE OF MONTANA DEPARTMENT 

OF ENVIRONMENTAL QUALITY,

Intervenor-Defendants,

and

TREASURE STATE RESOURCES 

ASSOCIATION OF MONTANA,

Intervenor-Defendant-Appellant.

No. 19-35899

D.C. No.

4:16-cv-00052-

BMM
UPPER MISSOURI WATERKEEPER V. USEPA 3

UPPER MISSOURI WATERKEEPER,

Plaintiff-Appellee,

v.

U.S. ENVIRONMENTAL PROTECTION 

AGENCY; MICHAEL REGAN, 

Administrator, United States 

Environmental Protection Agency,

Defendants,

NATIONAL ASSOCIATION OF CLEAN 

WATER AGENCIES; THE MONTANA 

LEAGUE OF CITIES AND TOWNS;

TREASURE STATE RESOURCES 

ASSOCIATION OF MONTANA,

Intervenor-Defendants,

and

STATE OF MONTANA DEPARTMENT 

OF ENVIRONMENTAL QUALITY,

Intervenor-Defendant-Appellant.

No. 20-35135

D.C. No.

4:16-cv-00052-

BMM
4 UPPER MISSOURI WATERKEEPER V. USEPA

UPPER MISSOURI WATERKEEPER,

Plaintiff-Appellee,

v.

U.S. ENVIRONMENTAL PROTECTION 

AGENCY; MICHAEL REGAN, 

Administrator, United States 

Environmental Protection Agency,

Defendants-Appellants,

and

NATIONAL ASSOCIATION OF CLEAN 

WATER AGENCIES; THE MONTANA 

LEAGUE OF CITIES AND TOWNS;

TREASURE STATE RESOURCES 

ASSOCIATION OF MONTANA; STATE 

OF MONTANA DEPARTMENT OF 

ENVIRONMENTAL QUALITY,

Intervenor-Defendants.

No. 20-35136

D.C. No.

4:16-cv-00052-

BMM
UPPER MISSOURI WATERKEEPER V. USEPA 5

UPPER MISSOURI WATERKEEPER,

Plaintiff-Appellant,

v.

U.S. ENVIRONMENTAL PROTECTION 

AGENCY; MICHAEL REGAN, 

Administrator, United States 

Environmental Protection Agency,

Defendants-Appellees,

NATIONAL ASSOCIATION OF CLEAN 

WATER AGENCIES; THE MONTANA 

LEAGUE OF CITIES AND TOWNS;

TREASURE STATE RESOURCES 

ASSOCIATION OF MONTANA; STATE 

OF MONTANA DEPARTMENT OF 

ENVIRONMENTAL QUALITY,

Intervenor-Defendants-Appellees.

No. 20-35137

D.C. No.

4:16-cv-00052-

BMM

OPINION

Appeals from the United States District Court

for the District of Montana

Brian M. Morris, Chief District Judge, Presiding

Argued and Submitted March 4, 2021

Portland, Oregon

Filed October 6, 2021
6 UPPER MISSOURI WATERKEEPER V. USEPA

Before: Danny J. Boggs,** Richard A. Paez, and

Paul J. Watford, Circuit Judges.

Opinion by Judge Watford

SUMMARY***

Clean Water Act

The panel reversed the portion of the district court’s 

summary judgment order challenged in Nos. 19-35898, 19-

35899, 20-35135, and 20-35136, and affirmed the portion of 

the summary judgment order challenged in No. 20-35137, in 

actions challenging the U.S. Environmental Protection 

Agency’s approval of Montana’s variance request from 

approved water quality standards that were adopted under 

the Clean Water Act.

The Clean Water Act requires States to adopt water 

quality standards regulating pollutants in their navigable 

waters. The standards consist of two components: (1) the 

designated uses for the water body, such as supporting 

aquatic life or recreational use; and (2) the “water quality 

criteria” necessary to protect those uses. 33 U.S.C. 

§ 1313(c)(2)(A); 40 C.F.R. §§ 131.3(b), 131.11(a). States 

submit proposed water quality standards to the EPA for 

review and approval. 

** The Honorable Danny J. Boggs, United States Circuit Judge for 

the U.S. Court of Appeals for the Sixth Circuit, sitting by designation.

*** This summary constitutes no part of the opinion of the court. It 

has been prepared by court staff for the convenience of the reader.
UPPER MISSOURI WATERKEEPER V. USEPA 7

The EPA approved Montana’s water quality standards in 

2015. In 2017, Montana sought, and obtained, EPA’s 

approval of a variance in the water quality standard, which 

covered 36 municipal wastewater treatment facilities for a 

term of up to 17 years. The variance allowed those facilities 

to discharge more nitrogen and phosphorus into wadeable 

streams than would be permitted under the base water 

standards approved in 2015. Plaintiff Upper Missouri 

Waterkeeper contended that the EPA approval of the 

variance violated the Administrative Procedure Act. The 

district court granted partial vacatur of the EPA’s approval 

of the variance, and stayed its decision pending resolution of 

the appeals.

First, the panel considered Waterkeeper’s cross-appeal, 

which contended that a provision of the Clean Water Act, 

33 U.S.C. § 1313(c)(2)(A), precluded the EPA from taking 

compliance costs into account when approving the variance 

requests. Applying Chevron analysis, the panel held at step 

one, that Congress had not directly spoken to the precise 

question at issue. Section 1313(c)(2)(A) does not speak at 

all to whether the EPA may consider compliance costs when 

approving a State’s proposed water quality standards or, by 

extension, when approving a State’s variance request. At 

step two, the panel held that the EPA reasonably construed 

§ 1313(c)(2)(A) as permitting it to consider compliance costs 

when approving water quality standards and variance 

requests. The panel concluded that the EPA’s regulations 

reasonably interpreted the Clean Water Act as allowing 

consideration of compliance costs when the agency approves 

water quality standards and variance requests.

Next, the panel turned to the EPA’s appeal, which 

challenged the district court’s partial vacatur of the agency’s 

decision approving Montana’s variance request. The district 
8 UPPER MISSOURI WATERKEEPER V. USEPA

court held that the variance’s term of up to 17 years was 

invalid because it did not require compliance with the 

highest attainable condition at the outset of the term, and did 

not require compliance with Montana’s base quality water 

standards by the end of the term. The panel disagreed, and 

held that the EPA’s variance regulation unambiguously 

provided that compliance with the highest attainable 

condition was not required at the outset. The district court 

did not identify any provision in the EPA’s variance 

regulation supporting its view that the variance must require 

compliance with the base water quality standards by the end 

of the variance’s term. As reflected in the variance at issue 

here, the EPA’s regulations included numerous features to 

ensure that dischargers and waterbodies subject to variances 

continued to improve water quality. The panel concluded 

that the regulatory framework was consistent with the goals 

of the Clean Water Act, which as reasonably construed by 

the EPA, included supporting aquatic life and recreational 

uses whenever attainable.

The panel remanded to the district court with instructions 

to deny Waterkeeper’s motion for summary judgment and to 

grant the EPA’s and intervenor-defendants’ motion for 

summary judgment in full.

COUNSEL

Janette K. Brimmer (argued), Earthjustice, Seattle, 

Washington, for Plaintiff-Appellee/Cross-Appellant.

John L. Smeltzer (argued), David Gunter, and Alan D. 

Greenberg, Attorneys; Eric Grant, Deputy Assistant 

Attorney General; Jonathan D. Brightbill, Principal Deputy 

Assistant Attorney General; Environment and Natural 
UPPER MISSOURI WATERKEEPER V. USEPA 9

Resources Division, United States Department of Justice,

Washington, D.C.; David Fatouhi, Peter Z. Ford, Heidi 

Nalven, and Diane McConkey, Office of General Counsel, 

United States Environmental Protection Agency; Erin 

Perkins and Elyana Sutin, Office of Regional Counsel, 

United States Environmental Protection Agency; for 

Defendants-Appellants/Cross-Appellees United States 

Environment Protection Agency and Michael Regan.

Kurt R. Moser (argued), Special Assistant Attorney General, 

State of Montana Department of Environmental Quality,

Helena, Montana, for Intervenor-DefendantAppellant/Cross-Appellee State of Montana Department of 

Environmental Quality.

Fredric P. Andes and Ashley E. Parr, Barnes & Thornburg 

LLP, Chicago, Illinois; Paul M. Drucker, Barnes & 

Thornburg LLP, Indianapolis, Indiana; Catherine A. 

Laughner, Chad E. Adams, and M. Christy S. McCann, 

Browning Kaleczyc Berry & Hoven P.C., Bozeman, 

Montana; for Intervenor-Defendant-Appellant/CrossAppellee National Association of Clean Water Agencies and 

Montana League of Cities and Towns.

Mark L. Stermitz and Jeffery J. Oven, Crowley Fleck PLLP, 

Billings, Montana, for Intervenor-DefendantAppellant/Cross-Appellee Treasure State Resources 

Association of Montana.
10 UPPER MISSOURI WATERKEEPER V. USEPA

OPINION

WATFORD, Circuit Judge:

Congress enacted the Clean Water Act “to restore and 

maintain the chemical, physical, and biological integrity of 

the Nation’s waters.” 33 U.S.C. § 1251(a). In furtherance 

of that objective, the Act requires States to adopt water 

quality standards regulating pollutants in their navigable 

waters. Water quality standards consist of two components: 

(1) the “designated uses” for the water body in question, 

such as supporting aquatic life or recreational use; and 

(2) the “water quality criteria” necessary to protect those 

uses, usually specified as the maximum concentration of a 

pollutant that may be present in the water. § 1313(c)(2)(A); 

40 C.F.R. §§ 131.3(b), 131.11(a). States must submit 

proposed water quality standards to the Environmental 

Protection Agency (EPA) for review and approval. 

33 U.S.C. § 1313(c). Once approved, water quality 

standards are used to set effluent limits in the permits that 

individual dischargers must obtain in order to discharge 

pollutants from a point source into waters covered by the 

Act. 40 C.F.R. § 122.44(d)(1); see 33 U.S.C. § 1342.

In 2014, the State of Montana adopted water quality 

standards governing two pollutants, nitrogen and 

phosphorus, in its “wadeable streams.” Montana assigned 

designated uses for wadeable streams that include the 

support of aquatic life and recreation, and to protect those 

uses it specified the maximum permissible concentrations of 

nitrogen and phosphorus. The EPA approved Montana’s 

water quality standards in 2015.

Under regulations issued by the EPA, States may obtain 

a variance from approved water quality standards (known as 

the “base” water quality standards) if compliance with such 
UPPER MISSOURI WATERKEEPER V. USEPA 11

standards is shown to be infeasible. See 40 C.F.R. § 131.14. 

A variance is a narrow, time-limited exemption from the 

base water quality standards, applicable to specific 

pollutants and to specific dischargers or a particular water 

body. §§ 131.3(o), 131.14(a). The EPA may approve a 

variance when the State demonstrates that compliance with 

the base water quality standards is not feasible for one of 

several specified reasons. §§ 131.14(b)(2)(i)(A), 131.10(g). 

One of those reasons, and the reason relevant in this case, is 

that implementing the pollution controls necessary to attain 

compliance with the base water quality standards “would 

result in substantial and widespread economic and social 

impact.” § 131.10(g)(6).

To be approved, a variance must set interim limits that, 

although less stringent than those imposed by the base water 

quality standards, nonetheless “represent the highest 

attainable condition of the water body or waterbody segment 

applicable throughout the term of the [water quality 

standards] variance.” § 131.14(b)(1)(ii). The term of a 

variance may last “only . . . as long as necessary to achieve 

the highest attainable condition.” § 131.14(b)(1)(iv).

In 2017, Montana sought EPA approval of the variance 

at issue in this appeal, which covers 36 municipal 

wastewater treatment facilities for a term of up to 17 years. 

The variance allows those facilities to discharge more 

nitrogen and phosphorus into wadeable streams than would 

be permitted under the base water quality standards 

approved in 2015. In support of the proposed variance, 

Montana submitted evidence demonstrating that these 

36 facilities could not attain compliance with the base water 

quality standards unless they adopted reverse osmosis 

technology, and that the high cost of adopting such 

technology would result in substantial and widespread 
12 UPPER MISSOURI WATERKEEPER V. USEPA

economic and social impact on the surrounding 

communities.

After reviewing Montana’s evidence and conducting its 

own analysis, the EPA approved the variance. The EPA 

agreed with Montana’s assessment that (1) implementing 

reverse osmosis technology would be necessary to attain 

compliance with the base water quality standards, and (2) the 

cost of implementing such technology would result in 

substantial and widespread economic and social impact on 

the communities served by the 36 municipal wastewater 

treatment facilities. In reaching that conclusion, the EPA 

relied on economic guidance that it had previously issued, 

which provides that an average annual cost per household 

exceeding 2% of median household income in the affected 

community constitutes a substantial economic impact. The 

EPA’s analysis confirmed that costs of that magnitude would 

indeed be imposed on each of the affected communities. The 

EPA also determined that the interim limits imposed by the 

variance represented the highest attainable condition for all 

36 facilities, and that the variance’s term of up to 17 years 

would last only “as long as necessary to achieve the highest 

attainable condition.” 40 C.F.R. § 131.14(b)(1)(iv), (2)(ii).

In this action, plaintiff Upper Missouri Waterkeeper 

(Waterkeeper) does not challenge any of the EPA’s factual 

determinations. It instead contends that the EPA’s approval 

of Montana’s variance request violates the Administrative 

Procedure Act because it is “not in accordance with law.” 

5 U.S.C. § 706(2)(A). Specifically, Waterkeeper argues that 

the Clean Water Act prohibits the EPA from considering 

compliance costs when granting variance requests.

On cross-motions for summary judgment, the district 

court rejected Waterkeeper’s argument. The court 

concluded that the EPA has reasonably construed the Clean 
UPPER MISSOURI WATERKEEPER V. USEPA 13

Water Act as permitting it to grant variances based on the 

economic impact that would be caused by requiring 

compliance with the base water quality standards. The court 

nevertheless held that the EPA’s approval of the variance’s 

term of up to 17 years was arbitrary and capricious because 

it does not require compliance with the highest attainable 

condition at the beginning of the variance term and does not 

require compliance with Montana’s base water quality 

standards by the end of the term. The court granted partial 

vacatur of the EPA’s approval of the variance and stayed its 

decision pending resolution of these appeals.

On appeal, Waterkeeper urges us to reverse the district 

court’s rejection of its Administrative Procedure Act 

challenge to the EPA’s approval decision, while the EPA and 

the intervenor-defendants (the Montana Department of 

Environmental Quality, Treasure State Resources 

Association of Montana, Montana League of Cities and 

Towns, and National Association of Clean Water Agencies) 

urge us to reverse the district court’s partial vacatur of that 

decision. We affirm in part, reverse in part, and remand with

instructions to enter judgment in favor of the EPA and the 

intervenor-defendants.

I

We take up Waterkeeper’s cross-appeal first. It contends 

that the following provision of the Clean Water Act 

precludes the EPA from taking compliance costs into 

account when approving variance requests:

Whenever the State revises or adopts a new 

standard, such revised or new standard shall 

be submitted to the Administrator. Such 

revised or new water quality standard shall 

consist of the designated uses of the 
14 UPPER MISSOURI WATERKEEPER V. USEPA

navigable waters involved and the water 

quality criteria for such waters based upon 

such uses. Such standards shall be such as to 

protect the public health or welfare, enhance 

the quality of water and serve the purposes of 

this chapter. Such standards shall be 

established taking into consideration their use 

and value for public water supplies, 

propagation of fish and wildlife, recreational 

purposes, and agricultural, industrial, and 

other purposes, and also taking into 

consideration their use and value for 

navigation.

33 U.S.C. § 1313(c)(2)(A). This provision addresses the 

establishment of water quality standards, not the granting of 

variances, and thus appears at first blush to be of limited 

relevance to Waterkeeper’s argument. Water quality 

standards and variances, however, are closely linked in the 

regulatory framework created by the EPA after the Clean 

Water Act’s passage. A bit more background on that 

framework is necessary before proceeding.

The EPA has interpreted § 1313(c)(2)(A) as authorizing 

States to consider compliance costs when they first adopt 

water quality standards. In enforcing that provision’s 

directive that water quality standards “serve the purposes of 

this chapter,” the EPA has looked to the opening provision 

of the Clean Water Act, § 101, codified at 33 U.S.C. § 1251, 

to identify those purposes. Section 1251(a)(2) of the Act 

declares that “it is the national goal that wherever attainable, 

an interim goal of water quality which provides for the 

protection and propagation of fish, shellfish, and wildlife and 

provides for recreation in and on the water be achieved by 

July 1, 1983.” 33 U.S.C. § 1251(a)(2) (emphasis added). 
UPPER MISSOURI WATERKEEPER V. USEPA 15

Although the deadline set by this provision has passed, the 

EPA has reasonably construed § 1251(a)(2) as an ongoing 

expression of Congress’s intent that the stated goal be 

achieved (albeit much later than hoped for) whenever the 

specified uses are “attainable.” See 40 C.F.R. § 131.2.

The EPA’s regulations require States to adopt water 

quality standards that protect the uses described in 

§ 1251(a)(2) unless the State can show through a “use 

attainability analysis” that attaining the water quality 

necessary to support those uses is not feasible for any one of 

the several reasons referenced earlier. See 40 C.F.R. 

§ 131.10(g), (j); Water Quality Standards Regulatory 

Clarifications, 78 Fed. Reg. 54,518, 54,522–23 (Sept. 4, 

2013). Thus, a State may adopt a water quality standard that 

does not designate the uses described in § 1251(a)(2) if it can 

show that implementing the pollution controls necessary to 

protect those uses “would result in substantial and 

widespread economic and social impact.” 40 C.F.R. 

§ 131.10(g)(6). Economic impact, of course, involves 

consideration of the costs that would be imposed on the 

affected stakeholders.

1

The EPA adopted its variance regulation by building on 

this same framework. The agency recognized that States 

could decline to designate a use in the first instance (or 

1 The EPA’s regulations make clear that compliance costs may be 

considered only when designating the uses to be protected by water 

quality standards. Once those uses have been designated, States must 

adopt water quality criteria adequate to protect those uses, “based on 

sound scientific rationale.” 40 C.F.R. § 131.11(a)(1); see Mississippi 

Commission on Natural Resources v. Costle, 625 F.2d 1269, 1277 (5th 

Cir. 1980). A variance does not modify the water quality criteria alone. 

A variance is instead a time-limited modification of both the “designated 

use and criterion.” 40 C.F.R. § 131.3(o).
16 UPPER MISSOURI WATERKEEPER V. USEPA

remove a previously designated use) by conducting a use 

attainability analysis and making the required showing that 

attainment of such a use is not feasible. If approved, that 

action would remove the designated use and associated 

water quality criteria from the water quality standard as 

applied to all dischargers and all pollutants.

In light of this reality, the EPA concluded that variances 

“are an environmentally preferable tool over a designated 

use change because variances retain designated use 

protection for all pollutants as they apply to all sources with 

the exception of those specified in the variance.” 78 Fed. 

Reg. at 54,531. The variance procedure thus affords States 

a more targeted option when compliance with a water quality 

standard is unattainable only for certain dischargers or only 

with respect to certain pollutants. The variance regulation 

requires States to make the same showing required by a use 

attainability analysis, just one that is limited in scope to the 

specific dischargers and pollutants covered by the variance.

Waterkeeper recognizes this link between water quality 

standards and variances. Its contention under the 

Administrative Procedure Act is that the provision quoted at 

the outset, 33 U.S.C. § 1313(c)(2)(A), precludes the EPA 

from taking compliance costs into account when approving 

either water quality standards or variances. In assessing this 

contention, we employ the two-step framework established 

in Chevron U.S.A. Inc. v. Natural Resources Defense 

Council, Inc., 467 U.S. 837 (1984).

At step one, we ask whether “Congress has directly 

spoken to the precise question at issue.” Id. at 842. The 

answer here is no. Section 1313(c)(2)(A) does not speak at 

all to whether the EPA may consider compliance costs when 

approving a State’s proposed water quality standards or, by 

extension, when approving a State’s variance request. The 
UPPER MISSOURI WATERKEEPER V. USEPA 17

provision is silent on the precise question at issue, but if 

anything, its reference to protecting the “public health or 

welfare” favors the EPA’s interpretation. 33 U.S.C.

§ 1313(c)(2)(A) (emphasis added). The concept of the 

public welfare is broad enough to encompass a regulatory 

program’s impact on the economic welfare of a community, 

and an assessment of that impact requires consideration of 

costs.

It is true, as Waterkeeper argues, that § 1313(c)(2)(A) 

includes a list of uses and values that States must “tak[e] into 

consideration” when establishing water quality standards, 

without expressly mentioning the costs of compliance. But 

the inference that Waterkeeper asks us to draw—that 

Congress’s silence as to costs reflects an intention to forbid 

their consideration—is not supported by the text of the 

provision or the broader statutory context. Requiring States 

to formulate water quality standards by “taking into 

consideration” various uses and values does not tell us 

anything about whether Congress intended to mandate 

compliance with water quality standards regardless of how 

exorbitant the cost might prove to be. And nothing in the 

other provisions of the Clean Water Act suggests that 

Congress’s silence as to costs in § 1313(c)(2)(A) should be 

accorded special weight, as was true of the statutory 

provision at issue in Whitman v. American Trucking 

Associations, Inc., 531 U.S. 457 (2001), the principal case 

on which Waterkeeper relies.

In American Trucking, certain provisions of the Clean 

Air Act “explicitly permitted or required economic costs to 

be taken into account in implementing the air quality 

standards,” whereas the provision under review in that case 

did not, leading to the conclusion that Congress’s silence 

was intended to foreclose consideration of costs. Id. at 467. 
18 UPPER MISSOURI WATERKEEPER V. USEPA

The same cannot be said of the portion of the Clean Water 

Act we are reviewing, which precludes us from drawing the 

inference Waterkeeper urges about the supposed import of 

Congress’s silence as to costs in § 1313(c)(2)(A). Rather, as 

in Entergy Corp. v. Riverkeeper, Inc., 556 U.S. 208 (2009), 

we think Congress’s silence as to costs in § 1313(c)(2)(A) 

can be understood “to convey nothing more than a refusal to 

tie the agency’s hands as to whether cost-benefit analysis 

should be used, and if so to what degree.” Id. at 222 

(interpreting § 316(b) of the Clean Water Act, codified at 

33 U.S.C. § 1326(b)).

Having concluded that the statute is silent or ambiguous 

as to the precise question raised, we ask at step two of the 

Chevron analysis whether “the agency’s answer is based on 

a permissible construction of the statute.” Chevron, 

467 U.S. at 843. For two reasons, both alluded to above, we 

think the EPA has reasonably construed § 1313(c)(2)(A) as 

permitting it to consider compliance costs when approving 

water quality standards and variance requests.

First, the provision states that water quality standards 

shall protect the “public . . . welfare,” and that term can 

reasonably be understood to encompass consideration of 

whether compliance costs would cause substantial and 

widespread economic and social impact. And second, the 

EPA has reasonably construed § 1313(c)(2)(A)’s 

requirement that water quality standards “serve the purposes 

of this chapter” as incorporating the purposes referred to in 

33 U.S.C. § 1251(a)(2). Congress declared in § 1251(a)(2) 

that water quality necessary to protect aquatic life and 

recreational use is to be achieved “wherever attainable.” The 

statute does not define what factors may be taken into 

account when deciding whether a particular use is 

“attainable,” so it fell to the EPA to flesh out the meaning of 
UPPER MISSOURI WATERKEEPER V. USEPA 19

that term. The agency could perhaps have interpreted the

term to focus solely on whether achieving water quality of a 

particular level is technologically feasible, even if the costs 

involved would prove financially ruinous to the 

communities benefitting from the improvements. But it 

seems far more plausible that Congress used the term in the 

sense reflected in the EPA’s regulations—as including an 

assessment of whether achieving the necessary water quality 

is economically feasible, given the costs that would be 

imposed on the affected communities.

We thus conclude that the EPA’s regulations reasonably 

interpret the Clean Water Act as allowing consideration of 

compliance costs when the agency approves water quality 

standards and variance requests.

II

We turn now to the EPA’s appeal, which challenges the 

district court’s partial vacatur of the agency’s decision 

approving Montana’s variance request. The court held that 

the variance’s term of up to 17 years is invalid because it 

(1) does not require compliance with the highest attainable 

condition at the outset of the term, and (2) does not require 

compliance with Montana’s base water quality standards by 

the end of the term. The district court believed these 

requirements were imposed by the EPA’s own variance 

regulation, but the plain language of the regulation 

unambiguously provides otherwise. We therefore have no 

need to decide whether the EPA’s interpretation of its 

regulation is entitled to deference under Kisor v. Wilkie, 

139 S. Ct. 2400 (2019).
20 UPPER MISSOURI WATERKEEPER V. USEPA

A

In ruling that compliance with the highest attainable 

condition must be achieved at the outset of a variance’s term, 

the district court relied on the EPA’s definition of a variance. 

The regulation defines the term “water quality standards 

variance” as a “time-limited designated use and criterion for 

a specific pollutant(s) or water quality parameter(s) that 

reflect the highest attainable condition during the term of the 

[water quality standards] variance.” 40 C.F.R. § 131.3(o) 

(emphasis added). The court concluded that the phrase 

“during the term” requires compliance with the highest 

attainable condition at the beginning of the variance’s term. 

On appeal, in defending the district court’s ruling, 

Waterkeeper points to another provision of the regulation, 

which states that the interim limits imposed by the variance 

must represent “the highest attainable condition of the water 

body or waterbody segment applicable throughout the term

of the [water quality standards] variance.” § 131.14(b)(1)(ii) 

(emphasis added). Waterkeeper contends that the phrase 

“throughout the term” has the same meaning as the phrase 

“during the term” in § 131.3(o), and that both require 

compliance with the highest attainable condition at the very 

outset of the term.

We do not think either phrase can fairly be read in the 

manner that the district court and Waterkeeper suggest. To 

be sure, both of the cited provisions provide that the highest 

attainable condition specified in the variance shall apply

throughout (or during) the variance’s term, from the 

beginning of the term to the end. But those provisions do 

not state that an individual discharger must be in compliance 

with the highest attainable condition on day one.

Instead, the EPA’s variance regulation unambiguously 

provides that compliance with the highest attainable 
UPPER MISSOURI WATERKEEPER V. USEPA 21

condition is not required at the outset. A variance request 

may be approved only when a State can show that 

compliance with the base water quality standards cannot 

feasibly be attained. § 131.14(b)(2)(i)(A). If approved, the 

variance replaces the base water quality standard with the 

most rigorous standard that can feasibly be attained—the 

“highest attainable condition.” § 131.14(b)(1)(ii). The 

regulation then provides that a variance may remain in effect 

only “as long as necessary to achieve the highest attainable 

condition.” § 131.14(b)(1)(iv) (emphasis added). That 

provision makes clear that the purpose of a variance is to 

provide the time needed to achieve this attainable interim 

standard, which means, of course, that compliance with the 

highest attainable condition is required by the end of the 

variance’s term, not at the beginning.

B

The district court did not identify any provision in the 

EPA’s variance regulation supporting its view that a 

variance must require compliance with the base water 

quality standards by the end of the variance’s term. We have 

found nothing in the regulation to support that view either. 

As just noted, the regulation explicitly states that the term of 

the variance may last only as long as necessary to achieve 

compliance with the highest attainable condition—not with 

the base water quality standards. 40 C.F.R. 

§ 131.14(b)(1)(iv). As this provision reflects, the purpose of 

a variance is to make incremental progress toward 

compliance with the base water quality standards, but the 

ultimate goal by the end of the variance’s term is to achieve 

compliance with the highest attainable condition. Indeed, if 

compliance with the base water quality standards were

feasible within a reasonably foreseeable timeframe—say, by 

the end of the variance’s term—there would be no basis for 
22 UPPER MISSOURI WATERKEEPER V. USEPA

granting a variance in the first place. When attainment of 

the base water quality standards is feasible within a 

reasonably foreseeable timeframe, a State may instead use a 

permit compliance schedule to set a specific deadline by 

which compliance with the base water quality standards will 

be achieved. § 122.47; see Water Quality Standards 

Regulatory Revisions, 80 Fed. Reg. 51,020, 51,039–40 

(Aug. 21, 2015).

In defense of the district court’s ruling, Waterkeeper 

contends that unless a variance requires compliance with the 

base water quality standards by the end of the term, States 

would be free to postpone compliance with the base 

standards indefinitely simply by securing one variance after 

another, in conflict with the goals of the Clean Water Act. 

That contention reflects a misunderstanding of the nature 

and purpose of a variance. A variance may be granted only 

when compliance with the base water quality standards is not 

feasible for one of the reasons specified in the EPA’s 

regulations. To be approved, the variance must require 

compliance with the highest attainable condition that is

feasible, and the variance may last only as long as necessary 

to achieve compliance with the highest attainable condition. 

If at the end of the variance’s term compliance with the base 

water quality standards has become feasible, another 

variance may not be granted. And, to obtain another 

variance, the State must submit an application subject to the 

same degree of EPA scrutiny and public participation as was 

the application for the initial variance. In the interim, while 

compliance with the base water quality standards remains 

unattainable, the variance’s requirements ensure that 

incremental progress toward attainment of the base 

standards is being made.
UPPER MISSOURI WATERKEEPER V. USEPA 23

The variance at issue here reflects these safeguards. In 

accordance with the regulation, the variance states: 

“Through the permitting process and the specific details of 

each facility, the time required must be as short as possible 

to meet the highest attainable condition.” This period may 

be “up to 17 years,” but the period permitted for an 

individual facility carefully tracks the steps the facility must 

take to achieve compliance with the highest attainable 

condition. If a facility reaches the highest attainable 

condition but still cannot attain compliance with the base 

water quality standards, the facility must implement a 

“pollutant minimization program”—that is, “a structured set 

of activities to improve processes and pollutant controls”—

as detailed in the variance. The variance is also subject to 

close review every three years. Thus, as reflected in the 

variance at issue here, the EPA’s regulations include 

numerous features to ensure that dischargers and 

waterbodies subject to variances continue to improve water 

quality.

The regulatory framework discussed above is fully 

consistent with the goals of the Clean Water Act, which, as 

reasonably construed by the EPA, include supporting 

aquatic life and recreational uses “wherever attainable.” 

33 U.S.C. § 1251(a)(2).

* * *

We reverse the portion of the district court’s summary 

judgment order challenged in Nos. 19-35898, 19-35899, 20-

35135, and 20-35136, and affirm the portion of the summary 

judgment order challenged in No. 20-35137. We remand to 

the district court with instructions to deny Waterkeeper’s 

motion for summary judgment and to grant the EPA’s and 
24 UPPER MISSOURI WATERKEEPER V. USEPA

intervenor-defendants’ motions for summary judgment in 

full.

AFFIRMED in part, REVERSED in part, and 

REMANDED with instructions.

The parties shall bear their own costs on appeal.