(Slip Opinion) OCTOBER TERM, 2005 1 

Syllabus 

NOTE: Where it is feasible, a syllabus (headnote) will be released, as is

being done in connection with this case, at the time the opinion is issued.

The syllabus constitutes no part of the opinion of the Court but has been

prepared by the Reporter of Decisions for the convenience of the reader. 

See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337. 

SUPREME COURT OF THE UNITED STATES 

Syllabus 

RAPANOS ET UX., ET AL. v. UNITED STATES 

CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR 

THE SIXTH CIRCUIT 

No. 04–1034. Argued February 21, 2006—Decided June 19, 2006* 

As relevant here, the Clean Water Act (CWA or Act) makes it unlawful 

to discharge dredged or fill material into “navigable waters” without

a permit, 33 U. S. C. §§1311(a), 1342(a), and defines “navigable waters” as “the waters of the United States, including the territorial

seas,” §1362(7). The Army Corps of Engineers (Corps), which issues 

permits for the discharge of dredged or fill material into navigable

waters, interprets “the waters of the United States” expansively to

include not only traditional navigable waters, 33 CFR §328.3(a)(1),

but also other defined waters, §328.3(a)(2), (3); “[t]ributaries” of such 

waters, §328.3(a)(5); and wetlands “adjacent” to such waters and 

tributaries, §328.3(a)(7). “[A]djacent” wetlands include those “bordering, contiguous [to], or neighboring” waters of the United States even

when they are “separated from [such] waters . . . by man-made dikes 

. . . and the like.” §328.3(c). 

These cases involve four Michigan wetlands lying near ditches or 

man-made drains that eventually empty into traditional navigable 

waters. In No. 04–1034, the United States brought civil enforcement

proceedings against the Rapanos petitioners, who had backfilled

three of the areas without a permit. The District Court found federal 

jurisdiction over the wetlands because they were adjacent to “waters

of the United States” and held petitioners liable for CWA violations. 

Affirming, the Sixth Circuit found federal jurisdiction based on the 

sites’ hydrologic connections to the nearby ditches or drains, or to

more remote navigable waters. In No. 04–1384, the Carabell petitioners were denied a permit to deposit fill in a wetland that was 

—————— 

*Together with No. 04–1384, Carabell et al. v. United States Army 

Corps of Engineers et al., also on certiorari to the same court. 
2 RAPANOS v. UNITED STATES 

Syllabus 

separated from a drainage ditch by an impermeable berm. The 

Carabells sued, but the District Court found federal jurisdiction over 

the site. Affirming, the Sixth Circuit held that the wetland was adjacent to navigable waters. 

Held: The judgments are vacated, and the cases are remanded. 

No. 04–1034, 376 F. 3d 629, and No. 04–1384, 391 F. 3d 704, vacated 

and remanded. 

JUSTICE SCALIA, joined by THE CHIEF JUSTICE, JUSTICE THOMAS, and 

JUSTICE ALITO, concluded: 

1. The phrase “the waters of the United States” includes only those 

relatively permanent, standing or continuously flowing bodies of water “forming geographic features” that are described in ordinary parlance as “streams,” “oceans, rivers, [and] lakes,” Webster’s New International Dictionary 2882 (2d ed.), and does not include channels 

through which water flows intermittently or ephemerally, or channels that periodically provide drainage for rainfall. The Corps’ expansive interpretation of that phrase is thus not “based on a permissible construction of the statute.” Chevron U. S. A. Inc. v. Natural 

Resources Defense Council, Inc., 467 U. S. 837, 843. Pp. 12–21. 

(a) While the meaning of “navigable waters” in the CWA is

broader than the traditional definition found in The Daniel Ball, 10 

Wall. 557, see Solid Waste Agency of Northern Cook Cty. v. Army 

Corps of Engineers, 531 U. S. 159, 167 (SWANCC); United States v. 

Riverside Bayview Homes, Inc., 474 U. S. 121, 133, the CWA authorizes federal jurisdiction only over “waters.” The use of the definite 

article “the” and the plural number “waters” show plainly that

§1362(7) does not refer to water in general, but more narrowly to water “[a]s found in streams,” “oceans, rivers, [and] lakes,” Webster’s 

New International Dictionary 2882 (2d ed.). Those terms all connote 

relatively permanent bodies of water, as opposed to ordinarily dry

channels through which water occasionally or intermittently flows.

Pp. 12–15. 

(b) The Act’s use of the traditional phrase “navigable waters” further confirms that the CWA confers jurisdiction only over relatively

permanent bodies of water. Traditionally, such “waters” included 

only discrete bodies of water, and the term still carries some of its 

original substance, SWANCC, supra, at 172. This Court’s subsequent

interpretation of “the waters of the United States” in the CWA likewise confirms this limitation. See, e.g., Riverside Bayview, supra, at 

131. And the CWA itself categorizes the channels and conduits that

typically carry intermittent flows of water separately from “navigable

waters,” including them in the definition of “‘point sources,’” 33 

U. S. C. §1362(14). Moreover, only the foregoing definition of “waters” is consistent with CWA’s stated policy “to recognize, preserve, 
Cite as: 547 U. S. ____ (2006) 3 

Syllabus 

and protect the primary responsibilities and rights of the States . . . 

to plan the development and use . . . of land and water resources

. . . .” §1251(b). In addition, “the waters of the United States” hardly

qualifies as the clear and manifest statement from Congress needed 

to authorize intrusion into such an area of traditional state authority 

as land-use regulation; and to authorize federal action that stretches 

the limits of Congress’s commerce power. See SWANCC, supra, at 

173. Pp. 15–21. 

2. A wetland may not be considered “adjacent to” remote “waters of

the United States” based on a mere hydrologic connection. Riverside 

Bayview rested on an inherent ambiguity in defining where the “water” ends and its abutting (“adjacent”) wetlands begin, permitting the 

Corps to rely on ecological considerations only to resolve that ambiguity in favor of treating all abutting wetlands as waters. Isolated 

ponds are not “waters of the United States” in their own right, see 

SWANCC, supra, at 167, 171, and present no boundary-drawing

problem justifying the invocation of such ecological factors. Thus, 

only those wetlands with a continuous surface connection to bodies 

that are “waters of the United States” in their own right, so that

there is no clear demarcation between the two, are “adjacent” to such

waters and covered by the Act. Establishing coverage of the Rapanos 

and Carabell sites requires finding that the adjacent channel contains a relatively permanent “wate[r] of the United States,” and that

each wetland has a continuous surface connection to that water, 

making it difficult to determine where the water ends and the wetland begins. Pp. 21–24. 

3. Because the Sixth Circuit applied an incorrect standard to determine whether the wetlands at issue are covered “waters,” and because of the paucity of the record, the cases are remanded for further

proceedings. P. 39. 

JUSTICE KENNEDY concluded that the Sixth Circuit correctly recognized that a water or wetland constitutes “navigable waters” under

the Act if it possesses a “significant nexus” to waters that are navigable in fact or that could reasonably be so made, Solid Waste Agency of 

Northern Cook Cty. v. Army Corps of Engineers, 531 U. S. 159, 167, 

172 (SWANCC), but did not consider all the factors necessary to determine that the lands in question had, or did not have, the requisite 

nexus. United States v. Riverside Bayview Homes, Inc., 474 U. S. 

121, and SWANCC establish the framework for the inquiry here. 

The nexus required must be assessed in terms of the Act’s goals and 

purposes. Congress enacted the law to “restore and maintain the

chemical, physical, and biological integrity of the Nation’s waters,” 33

U. S. C. §1251(a), and it pursued that objective by restricting dumping and filling in “waters of the United States,” §§1311(a), 1362(12). 
4 RAPANOS v. UNITED STATES 

Syllabus 

The rationale for the Act’s wetlands regulation, as the Corps has recognized, is that wetlands can perform critical functions related to the 

integrity of other waters—such as pollutant trapping, flood control,

and runoff storage. 33 C. F. R. §320.4(b)(2). Accordingly, wetlands 

possess the requisite nexus, and thus come within the statutory

phrase “navigable waters,” if the wetlands, alone or in combination

with similarly situated lands in the region, significantly affect the 

chemical, physical, and biological integrity of other covered waters 

understood as navigable in the traditional sense. When, in contrast, 

their effects on water quality are speculative or insubstantial, they 

fall outside the zone fairly encompassed by the term “navigable waters.” Because the Corps’ theory of jurisdiction in these cases—

adjacency to tributaries, however remote and insubstantial—goes beyond the Riverside Bayview holding, its assertion of jurisdiction cannot rest on that case. The breadth of the Corps’ existing standard for 

tributaries—which seems to leave room for regulating drains, 

ditches, and streams remote from any navigable-in-fact water and

carrying only minor water-volumes toward it—precludes that standard’s adoption as the determinative measure of whether adjacent

wetlands are likely to play an important role in the integrity of an

aquatic system comprising navigable waters as traditionally understood. Absent more specific regulations, the Corps must establish a

significant nexus on a case-by-case basis when seeking to regulate

wetlands based on adjacency to nonnavigable tributaries, in order to 

avoid unreasonable applications of the Act. In the instant cases the 

record contains evidence pointing to a possible significant nexus, but 

neither the agency nor the reviewing courts considered the issue in

these terms. Thus, the cases should be remanded for further proceedings. Pp. 1–30. 

SCALIA, J., announced the judgment of the Court, and delivered an

opinion, in which ROBERTS, C. J., and THOMAS and ALITO, JJ., joined. 

ROBERTS, C. J., filed a concurring opinion. KENNEDY, J., filed an opinion 

concurring in the judgment. STEVENS, J., filed a dissenting opinion, in 

which SOUTER, GINSBURG, and BREYER, JJ., joined. BREYER, J., filed a 

dissenting opinion. 
_________________ 

_________________ 

Cite as: 547 U. S. ____ (2006) 1 

Opinion of SCALIA, J. 

NOTICE: This opinion is subject to formal revision before publication in the

preliminary print of the United States Reports. Readers are requested to

notify the Reporter of Decisions, Supreme Court of the United States, Washington, D. C. 20543, of any typographical or other formal errors, in order

that corrections may be made before the preliminary print goes to press. 

SUPREME COURT OF THE UNITED STATES 

Nos. 04–1034 and 04–1384 

JOHN A. RAPANOS, ET UX., ET AL., PETITIONERS 

04–1034 v. 

UNITED STATES 

JUNE CARABELL ET AL., PETITIONERS 

04–1384 v. 

UNITED STATES ARMY CORPS OF ENGINEERS ET AL. 

ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF 

APPEALS FOR THE SIXTH CIRCUIT 

[June 19, 2006] 

JUSTICE SCALIA announced the judgment of the Court, 

and delivered an opinion, in which THE CHIEF JUSTICE, 

JUSTICE THOMAS, and JUSTICE ALITO join. 

In April 1989, petitioner John A. Rapanos backfilled 

wetlands on a parcel of land in Michigan that he owned

and sought to develop. This parcel included 54 acres of

land with sometimes-saturated soil conditions. The nearest body of navigable water was 11 to 20 miles away. 339 

F. 3d 447, 449 (CA6 2003) (Rapanos I). Regulators had

informed Mr. Rapanos that his saturated fields were “waters of the United States,” 33 U. S. C. §1362(7), that could 

not be filled without a permit. Twelve years of criminal 

and civil litigation ensued. 

The burden of federal regulation on those who would

deposit fill material in locations denominated “waters of

the United States” is not trivial. In deciding whether to 
2 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

grant or deny a permit, the U. S. Army Corps of Engineers 

(Corps) exercises the discretion of an enlightened despot, 

relying on such factors as “economics,” “aesthetics,” “recreation,” and “in general, the needs and welfare of the

people,” 33 CFR §320.4(a) (2004).1 The average applicant

for an individual permit spends 788 days and $271,596 in

completing the process, and the average applicant for a 

nationwide permit spends 313 days and $28,915—not 

counting costs of mitigation or design changes. Sunding & 

Zilberman, The Economics of Environmental Regulation 

by Licensing: An Assessment of Recent Changes to the

Wetland Permitting Process, 42 Natural Resources J. 59, 

74–76 (2002). “[O]ver $1.7 billion is spent each year by 

the private and public sectors obtaining wetlands permits.” Id., at 81. These costs cannot be avoided, because 

the Clean Water Act “impose[s] criminal liability,” as well

as steep civil fines, “on a broad range of ordinary industrial and commercial activities.” Hanousek v. United 

States, 528 U. S. 1102, 1103 (2000) (THOMAS, J., dissenting from denial of certiorari). In this litigation, for example, for backfilling his own wet fields, Mr. Rapanos faced 

63 months in prison and hundreds of thousands of dollars

in criminal and civil fines. See United States v. Rapanos,

235 F. 3d 256, 260 (CA6 2000).

The enforcement proceedings against Mr. Rapanos are a 

small part of the immense expansion of federal regulation 

of land use that has occurred under the Clean Water Act— 

—————— 

1 In issuing permits, the Corps directs that “[a]ll factors which may be 

relevant to the proposal must be considered including the cumulative 

effects thereof: among those are conservation, economics, aesthetics, 

general environmental concerns, wetlands, historic properties, fish and

wildlife values, flood hazards, floodplain values, land use, navigation, 

shore erosion and accretion, recreation, water supply and conservation, 

water quality, energy needs, safety, food and fiber production, mineral 

needs, considerations of property ownership and, in general, the needs 

and welfare of the people.” §320.4(a). 
Cite as: 547 U. S. ____ (2006) 3 

Opinion of SCALIA, J. 

without any change in the governing statute—during the

past five Presidential administrations. In the last three 

decades, the Corps and the Environmental Protection Agency

(EPA) have interpreted their jurisdiction over “the waters of

the United States” to cover 270-to-300 million acres of 

swampy lands in the United States—including half of 

Alaska and an area the size of California in the lower 48 

States. And that was just the beginning. The Corps has

also asserted jurisdiction over virtually any parcel of land

containing a channel or conduit—whether man-made or 

natural, broad or narrow, permanent or ephemeral—

through which rainwater or drainage may occasionally or 

intermittently flow. On this view, the federally regulated

“waters of the United States” include storm drains, roadside ditches, ripples of sand in the desert that may contain

water once a year, and lands that are covered by floodwaters once every 100 years. Because they include the land

containing storm sewers and desert washes, the statutory

“waters of the United States” engulf entire cities and

immense arid wastelands. In fact, the entire land area of 

the United States lies in some drainage basin, and an

endless network of visible channels furrows the entire 

surface, containing water ephemerally wherever the rain 

falls. Any plot of land containing such a channel may 

potentially be regulated as a “water of the United States.” 

I 

Congress passed the Clean Water Act (CWA or Act) in

1972. The Act’s stated objective is “to restore and maintain the chemical, physical, and biological integrity of the 

Nation’s waters.” 86 Stat. 816, 33 U. S. C. §1251(a). The 

Act also states that “[i]t is the policy of Congress to recognize, preserve, and protect the primary responsibilities 

and rights of States to prevent, reduce, and eliminate

pollution, to plan the development and use (including

restoration, preservation, and enhancement) of land and 
4 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

water resources, and to consult with the Administrator in 

the exercise of his authority under this chapter.” §1251(b).

One of the statute’s principal provisions is 33 U. S. C. 

§1311(a), which provides that “the discharge of any pollutant by any person shall be unlawful.” “The discharge of a

pollutant” is defined broadly to include “any addition of 

any pollutant to navigable waters from any point source,”

§1362(12), and “pollutant” is defined broadly to include not

only traditional contaminants but also solids such as

“dredged spoil, . . . rock, sand, [and] cellar dirt,” §1362(6). 

And, most relevant here, the CWA defines “navigable 

waters” as “the waters of the United States, including the

territorial seas.” §1362(7). 

The Act also provides certain exceptions to its prohibition of “the discharge of any pollutant by any person.” 

§1311(a). Section 1342(a) authorizes the Administrator of 

the EPA to “issue a permit for the discharge of any pollutant, . . . notwithstanding section 1311(a) of this title.” 

Section 1344 authorizes the Secretary of the Army, acting

through the Corps, to “issue permits . . . for the discharge 

of dredged or fill material into the navigable waters at

specified disposal sites.” §1344(a), (d). It is the discharge

of “dredged or fill material”—which, unlike traditional 

water pollutants, are solids that do not readily wash 

downstream—that we consider today. 

For a century prior to the CWA, we had interpreted the

phrase “navigable waters of the United States” in the Act’s 

predecessor statutes to refer to interstate waters that are 

“navigable in fact” or readily susceptible of being rendered 

so. The Daniel Ball, 10 Wall. 557, 563 (1871); see also 

United States v. Appalachian Elec. Power Co., 311 U. S. 

377, 406 (1940). After passage of the CWA, the Corps

initially adopted this traditional judicial definition for the 

Act’s term “navigable waters.” See 39 Fed. Reg. 12119, 

codified at 33 CFR §209.120(d)(1) (1974); see also Solid 

Waste Agency of Northern Cook Cty. v. Army Corps of 
Cite as: 547 U. S. ____ (2006) 5 

Opinion of SCALIA, J. 

Engineers, 531 U. S. 159, 168 (2001) (SWANCC). After a 

District Court enjoined these regulations as too narrow, 

Natural Resources Defense Council, Inc. v. Callaway, 392 

F. Supp. 685, 686 (DC 1975), the Corps adopted a far 

broader definition. See 40 Fed. Reg. 31324–31325 (1975);

42 Fed. Reg. 37144 (1977). The Corps’ new regulations

deliberately sought to extend the definition of “the waters

of the United States” to the outer limits of Congress’s 

commerce power. See id., at 37144, n. 2. 

The Corps’ current regulations interpret “the waters of

the United States” to include, in addition to traditional 

interstate navigable waters, 33 CFR §328.3(a)(1) (2004),

“[a]ll interstate waters including interstate wetlands,” 

§328.3(a)(2); “[a]ll other waters such as intrastate lakes, 

rivers, streams (including intermittent streams), mudflats, 

sandflats, wetlands, sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds, the use, degradation or 

destruction of which could affect interstate or foreign

commerce,” §328.3(a)(3); “[t]ributaries of [such] waters,” 

§328.3(a)(5); and “[w]etlands adjacent to [such] waters 

[and tributaries] (other than waters that are themselves

wetlands),” §328.3(a)(7). The regulation defines “adjacent” 

wetlands as those “bordering, contiguous [to], or neighboring” waters of the United States. §328.3(c). It specifically

provides that “[w]etlands separated from other waters of 

the United States by man-made dikes or barriers, natural

river berms, beach dunes and the like are ‘adjacent wetlands.’” Ibid. 

We first addressed the proper interpretation of 33

U. S. C. §1362(7)’s phrase “the waters of the United 

States” in United States v. Riverside Bayview Homes, Inc., 

474 U. S. 121 (1985). That case concerned a wetland that 

“was adjacent to a body of navigable water,” because “the 

area characterized by saturated soil conditions and wetland vegetation extended beyond the boundary of respondent’s property to . . . a navigable waterway.” Id., at 131; 
6 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

see also 33 CFR §328.3(b) (2004). Noting that “the transition from water to solid ground is not necessarily or even

typically an abrupt one,” and that “the Corps must necessarily choose some point at which water ends and land

begins,” 474 U. S., at 132, we upheld the Corps’ interpretation of “the waters of the United States” to include 

wetlands that “actually abut[ted] on” traditional navigable 

waters. Id., at 135. 

Following our decision in Riverside Bayview, the Corps

adopted increasingly broad interpretations of its own 

regulations under the Act. For example, in 1986, to “clarify” the reach of its jurisdiction, the Corps announced the

so-called “Migratory Bird Rule,” which purported to extend

its jurisdiction to any intrastate waters “[w]hich are or 

would be used as habitat” by migratory birds. 51 Fed. Reg. 

41217; see also SWANCC, supra, at 163–164. In addition, 

the Corps interpreted its own regulations to include

“ephemeral streams” and “drainage ditches” as “tributaries” that are part of the “waters of the United States,” see

33 CFR §328.3(a)(5), provided that they have a perceptible 

“ordinary high water mark” as defined in §328.3(e). 65 

Fed. Reg. 12823 (2000). This interpretation extended “the 

waters of the United States” to virtually any land feature 

over which rainwater or drainage passes and leaves a visible mark—even if only “the presence of litter and debris.” 

33 CFR §328.3(e). See also U. S. General Accounting 

Office, Report to the Chairman, Subcommittee on Energy

Policy, Natural Resources and Regulating Affairs, Committee on Government Reform, House of Representatives, 

Waters and Wetlands: Corps of Engineers Needs to Evaluate Its District Office Practices in Determining Jurisdiction, GAO–04–297, pp. 20–22 (Feb. 2004) (hereinafter 

GAO Report), http://www.gao.gov/new.items/d04297.pdf 

(all Internet materials as visited June 9, 2006, and available in Clerk of Court’s case file). Prior to our decision in 

SWANCC, lower courts upheld the application of this 
Cite as: 547 U. S. ____ (2006) 7 

Opinion of SCALIA, J. 

expansive definition of “tributaries” to such entities as

storm sewers that contained flow to covered waters during

heavy rainfall, United States v. Eidson, 108 F. 3d 1336, 

1340–1342 (CA11 1997), and dry arroyos connected to 

remote waters through the flow of groundwater over “centuries,” Quivira Mining Co. v. EPA, 765 F. 2d 126, 129 

(CA10 1985). 

In SWANCC, we considered the application of the Corps’ 

“Migratory Bird Rule” to “an abandoned sand and gravel

pit in northern Illinois.” 531 U. S., at 162. Observing that 

“[i]t was the significant nexus between the wetlands and 

‘navigable waters’ that informed our reading of the CWA 

in Riverside Bayview,” id., at 167 (emphasis added), we 

held that Riverside Bayview did not establish “that the 

jurisdiction of the Corps extends to ponds that are not

adjacent to open water.” 531 U. S., at 168 (emphasis 

deleted). On the contrary, we held that “nonnavigable, 

isolated, intrastate waters,” id., at 171—which, unlike the 

wetlands at issue in Riverside Bayview, did not “actually

abu[t] on a navigable waterway,” 531 U. S., at 167—were

not included as “waters of the United States.” 

Following our decision in SWANCC, the Corps did not

significantly revise its theory of federal jurisdiction under 

§1344(a). The Corps provided notice of a proposed rulemaking in light of SWANCC, 68 Fed. Reg. 1991 (2003), but 

ultimately did not amend its published regulations. Because SWANCC did not directly address tributaries, the 

Corps notified its field staff that they “should continue to

assert jurisdiction over traditional navigable waters . . .

and, generally speaking, their tributary systems (and

adjacent wetlands).” 68 Fed. Reg. 1998. In addition, 

because SWANCC did not overrule Riverside Bayview, the 

Corps continues to assert jurisdiction over waters 

“‘neighboring’” traditional navigable waters and their 

tributaries. 68 Fed. Reg. 1997 (quoting 33 CFR §328.3(c)

(2003)). 
8 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

 Even after SWANCC, the lower courts have continued to 

uphold the Corps’ sweeping assertions of jurisdiction over 

ephemeral channels and drains as “tributaries.” For 

example, courts have held that jurisdictional “tributaries”

include the “intermittent flow of surface water through

approximately 2.4 miles of natural streams and manmade

ditches (paralleling and crossing under I–64),” Treacy v. 

Newdunn Assoc., 344 F. 3d 407, 410 (CA4 2003); a “roadside ditch” whose water took “a winding, thirty-two-mile 

path to the Chesapeake Bay,” United States v. Deaton, 332 

F. 3d 698, 702 (CA4 2003); irrigation ditches and drains

that intermittently connect to covered waters, Community 

Assn. for Restoration of Environment v. Henry Bosma 

Dairy, 305 F. 3d 943, 954–955 (CA9 2002); Headwaters, 

Inc. v. Talent Irrigation Dist., 243 F. 3d 526, 534 (CA9 

2001); and (most implausibly of all) the “washes and arroyos” of an “arid development site,” located in the middle 

of the desert, through which “water courses . . . during

periods of heavy rain,” Save Our Sonoran, Inc. v. Flowers, 

408 F. 3d 1113, 1118 (CA9 2005).2 

These judicial constructions of “tributaries” are not

outliers. Rather, they reflect the breadth of the Corps’ 

determinations in the field. The Corps’ enforcement practices vary somewhat from district to district because “the 

definitions used to make jurisdictional determinations”

are deliberately left “vague.” GAO Report 26; see also id., 

at 22. But district offices of the Corps have treated, as 

—————— 

2We are indebted to the Sonoran court for a famous exchange, from 

the movie Casablanca (Warner Bros. 1942), which portrays most vividly

the absurdity of finding the desert filled with waters: 

“ ‘Captain Renault [Claude Rains]: “What in heaven’s name brought 

you to Casablanca?”

“ ‘Rick [Humphrey Bogart]: “My health. I came to Casablanca for the 

waters.” 

“ ‘Captain Renault: “The waters? What waters? We’re in the desert.” 

“ ‘Rick: “I was misinformed.’ ” 408 F. 3d, at 1117. 
Cite as: 547 U. S. ____ (2006) 9 

Opinion of SCALIA, J. 

“waters of the United States,” such typically dry land

features as “arroyos, coulees, and washes,” as well as other 

“channels that might have little water flow in a given 

year.” Id., at 20–21. They have also applied that definition to such manmade, intermittently flowing features as

“drain tiles, storm drains systems, and culverts.” Id., at 

24 (footnote omitted).

In addition to “tributaries,” the Corps and the lower

courts have also continued to define “adjacent” wetlands

broadly after SWANCC. For example, some of the Corps’

district offices have concluded that wetlands are “adjacent” to covered waters if they are hydrologically connected “through directional sheet flow during storm

events,” GAO Report 18, or if they lie within the “100-year

floodplain” of a body of water—that is, they are connected 

to the navigable water by flooding, on average, once every 

100 years, id., at 17, and n. 16. Others have concluded 

that presence within 200 feet of a tributary automatically 

renders a wetland “adjacent” and jurisdictional. Id., at 19. 

And the Corps has successfully defended such theories of 

“adjacency” in the courts, even after SWANCC’s excision of 

“isolated” waters and wetlands from the Act’s coverage. 

One court has held since SWANCC that wetlands separated from flood control channels by 70-foot-wide berms, 

atop which ran maintenance roads, had a “significant 

nexus” to covered waters because, inter alia, they lay

“within the 100 year floodplain of tidal waters.” Baccarat 

Fremont Developers, LLC v. Army Corps of Engineers, 425 

F. 3d 1150, 1152, 1157 (CA9 2005). In one of the cases 

before us today, the Sixth Circuit held, in agreement with 

“[t]he majority of courts,” that “while a hydrological connection between the non-navigable and navigable waters 

is required, there is no ‘direct abutment’ requirement” 

under SWANCC for “‘adjacency.’” 376 F. 3d 629, 639 

(2004) (Rapanos II). And even the most insubstantial 

hydrologic connection may be held to constitute a “signifi-
10 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

cant nexus.” One court distinguished SWANCC on the 

ground that “a molecule of water residing in one of these 

pits or ponds [in SWANCC] could not mix with molecules 

from other bodies of water”—whereas, in the case before 

it, “water molecules currently present in the wetlands will 

inevitably flow towards and mix with water from connecting bodies,” and “[a] drop of rainwater landing in the Site 

is certain to intermingle with water from the [nearby

river].” United States v. Rueth Development Co., 189 

F. Supp. 2d 874, 877–878 (ND Ind. 2002). 

II 

In these consolidated cases, we consider whether four 

Michigan wetlands, which lie near ditches or man-made

drains that eventually empty into traditional navigable

waters, constitute “waters of the United States” within the 

meaning of the Act. Petitioners in No. 04–1034, the Rapanos and their affiliated businesses, deposited fill material without a permit into wetlands on three sites near

Midland, Michigan: the “Salzburg site,” the “Hines Road 

site,” and the “Pine River site.” The wetlands at the Salzburg site are connected to a man-made drain, which 

drains into Hoppler Creek, which flows into the 

Kawkawlin River, which empties into Saginaw Bay and

Lake Huron. See Brief for United States in No. 04–1034, 

p. 11; 339 F. 3d, at 449. The wetlands at the Hines Road 

site are connected to something called the “Rose Drain,” 

which has a surface connection to the Tittabawassee 

River. App. to Pet. for Cert. in No. 04–1034, pp. A23, B20.

And the wetlands at the Pine River site have a surface 

connection to the Pine River, which flows into Lake 

Huron. Id., at A23–A24, B26. It is not clear whether the 

connections between these wetlands and the nearby drains

and ditches are continuous or intermittent, or whether the 

nearby drains and ditches contain continuous or merely 

occasional flows of water. 
Cite as: 547 U. S. ____ (2006) 11 

Opinion of SCALIA, J. 

The United States brought civil enforcement proceedings against the Rapanos petitioners. The District Court 

found that the three described wetlands were “within 

federal jurisdiction” because they were “adjacent to other

waters of the United States,” and held petitioners liable 

for violations of the CWA at those sites. Id., at B32–B35. 

On appeal, the United States Court of Appeals for the 

Sixth Circuit affirmed, holding that there was federal

jurisdiction over the wetlands at all three sites because 

“there were hydrological connections between all three 

sites and corresponding adjacent tributaries of navigable 

waters.” 376 F. 3d, at 643. 

Petitioners in No. 04–1384, the Carabells, were denied a 

permit to deposit fill material in a wetland located on a

triangular parcel of land about one mile from Lake St. 

Clair. A man-made drainage ditch runs along one side of 

the wetland, separated from it by a 4-foot-wide man-made

berm. The berm is largely or entirely impermeable to 

water and blocks drainage from the wetland, though it

may permit occasional overflow to the ditch. The ditch 

empties into another ditch or a drain, which connects to

Auvase Creek, which empties into Lake St. Clair. See 

App. to Pet. for Cert. in No. 04–1384, pp. 2a–3a.

After exhausting administrative appeals, the Carabell

petitioners filed suit in the District Court, challenging the 

exercise of federal regulatory jurisdiction over their site.

The District Court ruled that there was federal jurisdiction because the wetland “is adjacent to neighboring tributaries of navigable waters and has a significant nexus to

‘waters of the United States.’” Id., at 49a. Again the 

Sixth Circuit affirmed, holding that the Carabell wetland 

was “adjacent” to navigable waters. 391 F. 3d 704, 708 

(2004) (Carabell).

We granted certiorari and consolidated the cases, 546 

U. S. ___ (2005), to decide whether these wetlands constitute “waters of the United States” under the Act, and if so, 
12 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

whether the Act is constitutional. 

III 

The Rapanos petitioners contend that the terms “navigable waters” and “waters of the United States” in the Act

must be limited to the traditional definition of The Daniel 

Ball, which required that the “waters” be navigable in

fact, or susceptible of being rendered so. See 10 Wall., at 

563. But this definition cannot be applied wholesale to

the CWA. The Act uses the phrase “navigable waters” as 

a defined term, and the definition is simply “the waters of

the United States.” 33 U. S. C. §1362(7). Moreover, the 

Act provides, in certain circumstances, for the substitution of state for federal jurisdiction over “navigable waters 

. . . other than those waters which are presently used, or 

are susceptible to use in their natural condition or by

reasonable improvement as a means to transport interstate or foreign commerce . . . including wetlands adjacent

thereto.” §1344(g)(1) (emphasis added). This provision 

shows that the Act’s term “navigable waters” includes

something more than traditional navigable waters. We 

have twice stated that the meaning of “navigable waters” 

in the Act is broader than the traditional understanding of

that term, SWANCC, 531 U. S., at 167; Riverside Bayview, 

474 U. S., at 133.3 We have also emphasized, however, 

—————— 

3One possibility, which we ultimately find unsatisfactory, is that the 

“other” waters covered by 33 U. S. C. §1344(g)(1) are strictly intrastate 

waters that are traditionally navigable. But it would be unreasonable 

to interpret “the waters of the United States” to include all and only

traditional navigable waters, both interstate and intrastate. This 

would preserve the traditional import of the qualifier “navigable” in the 

defined term “navigable waters,” at the cost of depriving the qualifier

“of the United States” in the definition of all meaning. As traditionally 

understood, the latter qualifier excludes intrastate waters, whether

navigable or not. See The Daniel Ball, 10 Wall. 557, 563 (1871). In 

SWANCC, we held that “navigable” retained something of its traditional import. 531 U. S., at 172. A fortiori, the phrase “of the United 
Cite as: 547 U. S. ____ (2006) 13 

Opinion of SCALIA, J. 

that the qualifier “navigable” is not devoid of significance, 

SWANCC, supra, at 172. 

We need not decide the precise extent to which the

qualifiers “navigable” and “of the United States” restrict

the coverage of the Act. Whatever the scope of these

qualifiers, the CWA authorizes federal jurisdiction only

over “waters.” 33 U. S. C. §1362(7). The only natural 

definition of the term “waters,” our prior and subsequent 

judicial constructions of it, clear evidence from other provisions of the statute, and this Court’s canons of construction all confirm that “the waters of the United States” in 

§1362(7) cannot bear the expansive meaning that the

Corps would give it.

The Corps’ expansive approach might be arguable if the 

CSA defined “navigable waters” as “water of the United

States.” But “the waters of the United States” is something else. The use of the definite article (“the”) and the

plural number (“waters”) show plainly that §1362(7) does 

not refer to water in general. In this form, “the waters” 

refers more narrowly to water “[a]s found in streams and 

bodies forming geographical features such as oceans, 

rivers, [and] lakes,” or “the flowing or moving masses, as 

of waves or floods, making up such streams or bodies.” 

Webster’s New International Dictionary 2882 (2d ed.

1954) (hereinafter Webster’s Second).4 On this definition, 

“the waters of the United States” include only relatively 

—————— 

States” in the definition retains some of its traditional meaning. 4 JUSTICE KENNEDY observes, post, at 13 (opinion concurring in judgment), that the dictionary approves an alternative, somewhat poetic 

usage of “waters” as connoting “[a] flood or inundation; as the waters 

have fallen. ‘The peril of waters, wind, and rocks.’ Shak.” Webster’s 

Second 2882. It seems to us wholly unreasonable to interpret the 

statute as regulating only “floods” and “inundations” rather than 

traditional waterways—and strange to suppose that Congress had 

waxed Shakespearean in the definition section of an otherwise prosaic,

indeed downright tedious, statute. The duller and more commonplace 

meaning is obviously intended. 
14 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

permanent, standing or flowing bodies of water.5 The 

definition refers to water as found in “streams,” “oceans,” 

“rivers,” “lakes,” and “bodies” of water “forming geographical features.” Ibid. All of these terms connote continuously present, fixed bodies of water, as opposed to ordinarily dry channels through which water occasionally or 

intermittently flows. Even the least substantial of the 

definition’s terms, namely “streams,” connotes a continuous flow of water in a permanent channel—especially

when used in company with other terms such as “rivers,” 

“lakes,” and “oceans.”6 None of these terms encompasses 

—————— 

5By describing “waters” as “relatively permanent,” we do not necessarily exclude streams, rivers, or lakes that might dry up in extraordinary

circumstances, such as drought. We also do not necessarily exclude 

seasonal rivers, which contain continuous flow during some months of 

the year but no flow during dry months—such as the 290-day, continuously flowing stream postulated by JUSTICE STEVENS’ dissent (hereinafter the dissent), post, at 15. Common sense and common usage distinguish between a wash and seasonal river.

 Though scientifically precise distinctions between “perennial” and

“intermittent” flows are no doubt available, see, e.g., Dept. of Interior, 

U. S. Geological Survey, E. Hedman & W. Osterkamp, Streamflow

Characteristics Related to Channel Geometry of Streams in Western 

United States 15 (1982) (Water-Supply Paper 2193), we have no occasion in this litigation to decide exactly when the drying-up of a stream

bed is continuous and frequent enough to disqualify the channel as a

“wate[r] of the United States.” It suffices for present purposes that 

channels containing permanent flow are plainly within the definition, 

and that the dissent’s “intermittent” and “ephemeral” streams, post, at 

16 (opinion of STEVENS, J.)—that is, streams whose flow is “[c]oming

and going at intervals . . . [b]roken, fitful,” Webster’s Second 1296, or

“existing only, or no longer than, a day; diurnal . . . short-lived,” id., at 

857—are not. 6The principal definition of “stream” likewise includes reference to 

such permanent, geographically fixed bodies of water: “[a] current or

course of water or other fluid, flowing on the earth, as a river, brook, 

etc.” Id., at 2493 (emphasis added). The other definitions of “stream” 

repeatedly emphasize the requirement of continuous flow: “[a] steady 

flow, as of water, air, gas, or the like”; “[a]nything issuing or moving

with continued succession of parts”; “[a] continued current or course; 
Cite as: 547 U. S. ____ (2006) 15 

Opinion of SCALIA, J. 

transitory puddles or ephemeral flows of water. 

The restriction of “the waters of the United States” to 

exclude channels containing merely intermittent or 

ephemeral flow also accords with the commonsense understanding of the term. In applying the definition to 

“ephemeral streams,” “wet meadows,” storm sewers and 

culverts, “directional sheet flow during storm events,” 

drain tiles, man-made drainage ditches, and dry arroyos in

the middle of the desert, the Corps has stretched the term

“waters of the United States” beyond parody. The plain

language of the statute simply does not authorize this

“Land Is Waters” approach to federal jurisdiction. 

In addition, the Act’s use of the traditional phrase “navigable waters” (the defined term) further confirms that it

confers jurisdiction only over relatively permanent bodies 

of water. The Act adopted that traditional term from its

predecessor statutes. See SWANCC, 531 U. S., at 180 

(STEVENS, J., dissenting). On the traditional understanding, “navigable waters” included only discrete bodies of 

water. For example, in The Daniel Ball, we used the terms 

“waters” and “rivers” interchangeably. 10 Wall., at 563. 

And in Appalachian Electric, we consistently referred to 

—————— 

current; drift.” Ibid. (emphases added). The definition of the verb form 

of “stream” contains a similar emphasis on continuity: “[t]o issue or

flow in a stream; to issue freely or move in a continuous flow or course.” 

Ibid. (emphasis added). On these definitions, therefore, the Corps’ 

phrases “intermittent streams,” 33 CFR §328.3(a)(3) (2004), and 

“ephemeral streams,” 65 Fed. Reg. 12823 (2000), are—like Senator 

Bentsen’s “ ‘flowing gullies,’” post, at 16, n. 11 (opinion of STEVENS, J.)— 

useful oxymora. Properly speaking, such entities constitute extant 

“streams” only while they are “continuous[ly] flow[ing]”; and the usually dry channels that contain them are never “streams.” JUSTICE 

KENNEDY apparently concedes that “an intermittent flow can constitute 

a stream” only “while it is flowing,” post, at 13 (emphasis added)—

which would mean that the channel is a “water” covered by the Act only 

during those times when water flow actually occurs. But no one contends that federal jurisdiction appears and evaporates along with the 

water in such regularly dry channels. 
16 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

the “navigable waters” as “waterways.” 311 U. S., at 407– 

409. Plainly, because such “waters” had to be navigable in

fact or susceptible of being rendered so, the term did not 

include ephemeral flows. As we noted in SWANCC, the 

traditional term “navigable waters”—even though defined

as “the waters of the United States”—carries some of its 

original substance: “[I]t is one thing to give a word limited 

effect and quite another to give it no effect whatever.” 531 

U. S., at 172. That limited effect includes, at bare minimum, the ordinary presence of water. 

Our subsequent interpretation of the phrase “the waters

of the United States” in the CWA likewise confirms this 

limitation of its scope. In Riverside Bayview, we stated 

that the phrase in the Act referred primarily to “rivers,

streams, and other hydrographic features more conventionally identifiable as ‘waters’” than the wetlands adjacent to such features. 474 U. S., at 131 (emphasis added). 

We thus echoed the dictionary definition of “waters” as

referring to “streams and bodies forming geographical 

features such as oceans, rivers, [and] lakes.” Webster’s 

Second 2882 (emphasis added). Though we upheld in that 

case the inclusion of wetlands abutting such a “hydrographic featur[e]”—principally due to the difficulty of 

drawing any clear boundary between the two, see 474

U. S., at 132; Part IV, infra—nowhere did we suggest that 

“the waters of the United States” should be expanded to

include, in their own right, entities other than “hydrographic features more conventionally identifiable as ‘waters.’” Likewise, in both Riverside Bayview and SWANCC, 

we repeatedly described the “navigable waters” covered by

the Act as “open water” and “open waters.” See Riverside 

Bayview, supra, at 132, and n. 8, 134; SWANCC, supra, at 

167, 172. Under no rational interpretation are typically 

dry channels described as “open waters.” 

Most significant of all, the CWA itself categorizes the 

channels and conduits that typically carry intermittent 
Cite as: 547 U. S. ____ (2006) 17 

Opinion of SCALIA, J. 

flows of water separately from “navigable waters,” by

including them in the definition of “‘point source.’” The 

Act defines “‘point source’” as “any discernible, confined 

and discrete conveyance, including but not limited to any 

pipe, ditch, channel, tunnel, conduit, well, discrete fissure, 

container, rolling stock, concentrated animal feeding 

operation, or vessel or other floating craft, from which

pollutants are or may be discharged.” 33 U. S. C. 

§1362(14). It also defines “‘discharge of a pollutant’” as

“any addition of any pollutant to navigable waters from 

any point source.” §1362(12)(A) (emphases added). The 

definitions thus conceive of “point sources” and “navigable 

waters” as separate and distinct categories. The definition 

of “discharge” would make little sense if the two categories 

were significantly overlapping. The separate classification 

of “ditch[es], channel[s], and conduit[s]”—which are terms

ordinarily used to describe the watercourses through

which intermittent waters typically flow—shows that these 

are, by and large, not “waters of the United States.”7 

—————— 

7 It is of course true, as the dissent and JUSTICE KENNEDY both observe, that ditches, channels, conduits and the like “can all hold water 

permanently as well as intermittently,” post, at 17 (opinion of STEVENS, 

J.); see also post, at 14–15 (opinion of KENNEDY, J.). But when they do, 

we usually refer to them as “rivers,” “creeks,” or “streams.” A permanently flooded ditch around a castle is technically a “ditch,” but (because it is permanently filled with water) we normally describe it as a

“moat.” See Webster’s Second 1575. And a permanently flooded manmade ditch used for navigation is normally described, not as a “ditch,” 

but as a “canal.” See id., at 388. Likewise, an open channel through 

which water permanently flows is ordinarily described as a “stream,”

not as a “channel,” because of the continuous presence of water. This 

distinction is particularly apt in the context of a statute regulating 

water quality, rather than (for example) the shape of stream beds. Cf. 

Jennison v. Kirk, 98 U. S. 453, 454–456 (1879) (referring to man-made 

channels as “ditches” when the alleged injury arose from physical 

damage to the banks of the ditch); PUD No. 1 of Jefferson Cty. v. 

Washington Dept. of Ecology, 511 U. S. 700, 709 (1994) (referring to a

water-filled tube as a “tunnel” in order to describe the shape of the 
18 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

Moreover, only the foregoing definition of “waters” is 

consistent with the CWA’s stated “policy of Congress to

recognize, preserve, and protect the primary responsibilities and rights of the States to prevent, reduce, and eliminate pollution, [and] to plan the development and use 

(including restoration, preservation, and enhancement) of 

land and water resources . . . .” §1251(b). This statement 

of policy was included in the Act as enacted in 1972, see 86

Stat. 816, prior to the addition of the optional state administration program in the 1977 amendments, see 91 

Stat. 1601. Thus the policy plainly referred to something 

beyond the subsequently added state administration

program of 33 U. S. C. §1344(g)–(l). But the expansive

theory advanced by the Corps, rather than “preserv[ing]

the primary rights and responsibilities of the States,” 

would have brought virtually all “plan[ning of] the development and use . . . of land and water resources” by the 

States under federal control. It is therefore an unlikely 

—————— 

conveyance, not the fact that it was water-filled), both cited post, at 17, 

n. 12 (opinion of STEVENS, J.). On its only natural reading, such a 

statute that treats “waters” separately from “ditch[es], channel[s], 

tunnel[s], and conduit[s],” thereby distinguishes between continuously

flowing “waters” and channels containing only an occasional or intermittent flow. 

It is also true that highly artificial, manufactured, enclosed conveyance systems—such as “sewage treatment plants,” post, at 15 (opinion 

of KENNEDY, J.), and the “mains, pipes, hydrants, machinery, buildings,

and other appurtenances and incidents” of the city of Knoxville’s

“system of waterworks,” Knoxville Water Co. v. Knoxville, 200 U. S. 22, 

27 (1906), cited post, at 17, n. 12 (opinion of STEVENS, J.)—likely do not 

qualify as “waters of the United States,” despite the fact that they may 

contain continuous flows of water. See post, at 15 (opinion of KENNEDY, 

J.); post, at 17, n. 12 (opinion of STEVENS, J.). But this does not contradict our interpretation, which asserts that relatively continuous flow is 

a necessary condition for qualification as a “water,” not an adequate 

condition. Just as ordinary usage does not treat typically dry beds as 

“waters,” so also it does not treat such elaborate, man-made, enclosed 

systems as “waters” on a par with “streams,” “rivers,” and “oceans.” 
Cite as: 547 U. S. ____ (2006) 19 

Opinion of SCALIA, J. 

reading of the phrase “the waters of the United States.”8 

Even if the phrase “the waters of the United States”

were ambiguous as applied to intermittent flows, our own 

canons of construction would establish that the Corps’ 

interpretation of the statute is impermissible. As we 

noted in SWANCC, the Government’s expansive interpretation would “result in a significant impingement of the

States’ traditional and primary power over land and water 

use.” 531 U. S., at 174. Regulation of land use, as through

the issuance of the development permits sought by petitioners in both of these cases, is a quintessential state and 

local power. See FERC v. Mississippi, 456 U. S. 742, 768, 

n. 30 (1982); Hess v. Port Authority Trans-Hudson Corporation, 513 U. S. 30, 44 (1994). The extensive federal 

jurisdiction urged by the Government would authorize the

Corps to function as a de facto regulator of immense

stretches of intrastate land—an authority the agency has 

shown its willingness to exercise with the scope of discretion that would befit a local zoning board. See 33 CFR 

§320.4(a)(1) (2004). We ordinarily expect a “clear and 

manifest” statement from Congress to authorize an unprecedented intrusion into traditional state authority. See 

BFP v. Resolution Trust Corporation, 511 U. S. 531, 544 

(1994). The phrase “the waters of the United States” 

hardly qualifies.

Likewise, just as we noted in SWANCC, the Corps’ 

—————— 

8 JUSTICE KENNEDY contends that the Corps’ preservation of the “responsibilities and rights” of the States is adequately demonstrated by

the fact that “33 States and the District of Columbia have filed an amici 

brief in this litigation” in favor of the Corps’ interpretation, post, at 20. 

But it makes no difference to the statute’s stated purpose of preserving 

States’ “rights and responsibilities,” §1251(b), that some States wish to

unburden themselves of them. Legislative and executive officers of the 

States may be content to leave “responsibilit[y]” with the Corps because

it is attractive to shift to another entity controversial decisions disputed

between politically powerful, rival interests. That, however, is not 

what the statute provides. 
20 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

interpretation stretches the outer limits of Congress’s 

commerce power and raises difficult questions about the 

ultimate scope of that power. See 531 U. S., at 173. (In

developing the current regulations, the Corps consciously

sought to extend its authority to the farthest reaches of 

the commerce power. See 42 Fed. Reg. 37127 (1977).) 

Even if the term “the waters of the United States” were 

ambiguous as applied to channels that sometimes host 

ephemeral flows of water (which it is not), we would expect a clearer statement from Congress to authorize an

agency theory of jurisdiction that presses the envelope of 

constitutional validity. See Edward J. DeBartolo Corp. v. 

Florida Gulf Coast Building & Constr. Trades Council, 

485 U. S. 568, 575 (1988).9 

In sum, on its only plausible interpretation, the phrase

“the waters of the United States” includes only those 

relatively permanent, standing or continuously flowing 

bodies of water “forming geographic features” that are

described in ordinary parlance as “streams[,] . . . oceans, 

rivers, [and] lakes.” See Webster’s Second 2882. The 

phrase does not include channels through which water 

—————— 

9 JUSTICE KENNEDY objects that our reliance on these two clearstatement rules is inappropriate because “the plurality’s interpretation 

does not fit the avoidance concerns that it raises,” post, at 19—that is, 

because our resolution both eliminates some jurisdiction that is clearly

constitutional and traditionally federal, and retains some that is 

questionably constitutional and traditionally local. But a clearstatement rule can carry one only so far as the statutory text permits. 

Our resolution, unlike JUSTICE KENNEDY’s, keeps both the overinclusion 

and the underinclusion to the minimum consistent with the statutory

text. JUSTICE KENNEDY’s reading—despite disregarding the text—fares

no better than ours as a precise “fit” for the “avoidance concerns” that 

he also acknowledges. He admits, post, at 25, that “the significant

nexus requirement may not align perfectly with the traditional extent

of federal authority” over navigable waters—an admission that “tests 

the limits of understatement,” Gonzales v. Oregon, 126 S. Ct. 904, 932 

(2005) (SCALIA, J., dissenting)—and it aligns even worse with the 

preservation of traditional state land-use regulation. 
Cite as: 547 U. S. ____ (2006) 21 

Opinion of SCALIA, J. 

flows intermittently or ephemerally, or channels that

periodically provide drainage for rainfall. The Corps’ 

expansive interpretation of the “the waters of the United

States” is thus not “based on a permissible construction of 

the statute.” Chevron U. S. A. Inc. v. Natural Resources 

Defense Council, Inc., 467 U. S. 837, 843 (1984). 

IV 

In Carabell, the Sixth Circuit held that the nearby ditch

constituted a “tributary” and thus a “water of the United

States” under 33 CFR §328.3(a)(5) (2004). See 391 F. 3d, at 

708–709. Likewise in Rapanos, the Sixth Circuit held that 

the nearby ditches were “tributaries” under §328(a)(5). 376

F. 3d, at 643. But Rapanos II also stated that, even if the 

ditches were not “waters of the United States,” the wetlands were “adjacent” to remote traditional navigable

waters in virtue of the wetlands’ “hydrological connection”

to them. See id., at 639–640. This statement reflects the 

practice of the Corps’ district offices, which may “assert

jurisdiction over a wetland without regulating the ditch

connecting it to a water of the United States.” GAO Report 23. We therefore address in this Part whether a 

wetland may be considered “adjacent to” remote “waters of 

the United States,” because of a mere hydrologic connection to them. 

In Riverside Bayview, we noted the textual difficulty in

including “wetlands” as a subset of “waters”: “On a purely

linguistic level, it may appear unreasonable to classify

‘lands,’ wet or otherwise, as ‘waters.’” 474 U. S., at 132. 

We acknowledged, however, that there was an inherent 

ambiguity in drawing the boundaries of any “waters”: 

“[T]he Corps must necessarily choose some point at

which water ends and land begins. Our common experience tells us that this is often no easy task: the 

transition from water to solid ground is not necessarily or even typically an abrupt one. Rather, between 
22 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

open waters and dry land may lie shallows, marshes, 

mudflats, swamps, bogs—in short, a huge array of areas that are not wholly aquatic but nevertheless fall

far short of being dry land. Where on this continuum 

to find the limit of ‘waters’ is far from obvious.” Ibid. 

Because of this inherent ambiguity, we deferred to the

agency’s inclusion of wetlands “actually abut[ting]” traditional navigable waters: “Faced with such a problem of

defining the bounds of its regulatory authority,” we held, 

the agency could reasonably conclude that a wetland that

“adjoin[ed]” waters of the United States is itself a part of

those waters. Id., at 132, 135, and n. 9. The difficulty of

delineating the boundary between water and land was

central to our reasoning in the case: “In view of the

breadth of federal regulatory authority contemplated by 

the Act itself and the inherent difficulties of defining precise bounds to regulable waters, the Corps’ ecological 

judgment about the relationship between waters and their

adjacent wetlands provides an adequate basis for a legal 

judgment that adjacent wetlands may be defined as waters under the Act.” Id., at 134 (emphasis added).10 

—————— 

10Since the wetlands at issue in Riverside Bayview actually abutted 

waters of the United States, the case could not possibly have held that 

merely “neighboring” wetlands came within the Corps’ jurisdiction. 

Obiter approval of that proposition might be inferred, however, from

the opinion’s quotation without comment of a statement by the Corps

describing covered “adjacent” wetlands as those “ ‘that form the border

of or are in reasonable proximity to other waters of the United States.’ ” 

474 U. S., at 134 (quoting 42 Fed. Reg. 37128 (1977); emphasis added). 

The opinion immediately reiterated, however, that adjacent wetlands 

could be regarded as “the waters of the United States” in view of “the

inherent difficulties of defining precise bounds to regulable waters,” 474 

U. S., at 134—a rationale that would have no application to physically

separated “neighboring” wetlands. Given that the wetlands at issue in 

Riverside Bayview themselves “actually abut[ted] on a navigable 

waterway,” id., at 135; given that our opinion recognized that unconnected wetlands could not naturally be characterized as “ ‘waters’ ” at 
Cite as: 547 U. S. ____ (2006) 23 

Opinion of SCALIA, J. 

When we characterized the holding of Riverside Bayview 

in SWANCC, we referred to the close connection between 

waters and the wetlands that they gradually blend into:

“It was the significant nexus between the wetlands and 

‘navigable waters’ that informed our reading of the CWA 

in Riverside Bayview Homes.” 531 U. S., at 167 (emphasis 

added). In particular, SWANCC rejected the notion that

the ecological considerations upon which the Corps relied 

in Riverside Bayview—and upon which the dissent repeatedly relies today, see post, at 10–11, 12, 13–14, 15, 18–19, 

21–22, 24–25—provided an independent basis for including entities like “wetlands” (or “ephemeral streams”) 

within the phrase “the waters of the United States.” 

SWANCC found such ecological considerations irrelevant 

to the question whether physically isolated waters come

within the Corps’ jurisdiction. It thus confirmed that 

Riverside Bayview rested upon the inherent ambiguity in

defining where water ends and abutting (“adjacent”) wetlands begin, permitting the Corps’ reliance on ecological 

considerations only to resolve that ambiguity in favor of 

treating all abutting wetlands as waters. Isolated ponds

were not “waters of the United States” in their own right,

see 531 U. S., at 167, 171, and presented no boundarydrawing problem that would have justified the invocation 

of ecological factors to treat them as such. 

Therefore, only those wetlands with a continuous surface connection to bodies that are “waters of the United 

States” in their own right, so that there is no clear demarcation between “waters” and wetlands, are “adjacent to” 

—————— 

all, id., at 132; and given the repeated reference to the difficulty of 

determining where waters end and wetlands begin; the most natural 

reading of the opinion is that a wetlands’ mere “reasonable proximity”

to waters of the United States is not enough to confer Corps jurisdiction. In any event, as discussed in our immediately following text, any

possible ambiguity has been eliminated by SWANCC, 531 U. S. 159 

(2001). 
24 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

such waters and covered by the Act. Wetlands with only

an intermittent, physically remote hydrologic connection

to “waters of the United States” do not implicate the 

boundary-drawing problem of Riverside Bayview, and thus 

lack the necessary connection to covered waters that we

described as a “significant nexus” in SWANCC. 531 U. S., 

at 167. Thus, establishing that wetlands such as those at 

the Rapanos and Carabell sites are covered by the Act

requires two findings: First, that the adjacent channel

contains a “wate[r] of the United States,” (i.e., a relatively

permanent body of water connected to traditional interstate navigable waters); and second, that the wetland has 

a continuous surface connection with that water, making 

it difficult to determine where the “water” ends and the 

“wetland” begins. 

V 

Respondents and their amici urge that such restrictions

on the scope of “navigable waters” will frustrate enforcement against traditional water polluters under 33 U. S. C. 

§§1311 and 1342. Because the same definition of “navigable waters” applies to the entire statute, respondents contend that water polluters will be able to evade the permitting requirement of §1342(a) simply by discharging their 

pollutants into noncovered intermittent watercourses that

lie upstream of covered waters. See Tr. of Oral Arg. 74–75. 

That is not so. Though we do not decide this issue, there

is no reason to suppose that our construction today significantly affects the enforcement of §1342, inasmuch as lower 

courts applying §1342 have not characterized intermittent 

channels as “waters of the United States.” The Act does 

not forbid the “addition of any pollutant directly to navigable waters from any point source,” but rather the “addition of any pollutant to navigable waters.” §1362(12)(A)

(emphasis added); §1311(a). Thus, from the time of the 

CWA’s enactment, lower courts have held that the dis-
Cite as: 547 U. S. ____ (2006) 25 

Opinion of SCALIA, J. 

charge into intermittent channels of any pollutant that 

naturally washes downstream likely violates §1311(a),

even if the pollutants discharged from a point source do

not emit “directly into” covered waters, but pass “through

conveyances” in between. United States v. Velsicol Chemical Corp., 438 F. Supp. 945, 946–947 (WD Tenn. 1976) (a 

municipal sewer system separated the “point source” and

covered navigable waters). See also Sierra Club v. El Paso 

Gold Mines, Inc., 421 F. 3d 1133, 1137, 1141 (CA10 2005) 

(2.5 miles of tunnel separated the “point source” and 

“navigable waters”).

In fact, many courts have held that such upstream, 

intermittently flowing channels themselves constitute 

“point sources” under the Act. The definition of “point

source” includes “any pipe, ditch, channel, tunnel, conduit,

well, discrete fissure, container, rolling stock, concentrated 

animal feeding operation, or vessel or other floating craft, 

from which pollutants are or may be discharged.” 33 

U. S. C. §1362(14). We have held that the Act “makes 

plain that a point source need not be the original source of 

the pollutant; it need only convey the pollutant to ‘navigable waters.’” South Fla. Water Management Dist. v. Miccosukee Tribe, 541 U. S. 95, 105 (2004). Cases holding the 

intervening channel to be a point source include United 

States v. Ortiz, 427 F. 3d 1278, 1281 (CA10 2005) (a storm 

drain that carried flushed chemicals from a toilet to the 

Colorado River was a “point source”), and Dague v. Burlington, 935 F. 2d 1343, 1354–1355 (CA2 1991) (a culvert 

connecting two bodies of navigable water was a “point

source”), rev’d on other grounds, 505 U. S. 557 (1992). 

Some courts have even adopted both the “indirect discharge” rationale and the “point source” rationale in the 

alternative, applied to the same facts. See, e.g., Concerned 

Area Residents for Environment v. Southview Farm, 34 

F. 3d 114, 118–119 (CA2 1994). On either view, however, 

the lower courts have seen no need to classify the inter-
26 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

vening conduits as “waters of the United States.” 

In contrast to the pollutants normally covered by the 

permitting requirement of §1342(a), “dredged or fill material,” which is typically deposited for the sole purpose of 

staying put, does not normally wash downstream,11 and 

thus does not normally constitute an “addition . . . to 

navigable waters” when deposited in upstream isolated 

wetlands. §§1344(a), 1362(12). The Act recognizes this 

distinction by providing a separate permitting program for

such discharges in §1344(a). It does not appear, therefore, 

that the interpretation we adopt today significantly reduces the scope of §1342 of the Act. 

Respondents also urge that the narrower interpretation

of “waters” will impose a more difficult burden of proof in

enforcement proceedings under §§1311(a) and 1342(a), by

requiring the agency to demonstrate the downstream flow

of the pollutant along the intermittent channel to tradi-

—————— 

11The dissent argues that “the very existence of words like ‘alluvium’ 

and ‘silt’ in our language suggests that at least some [dredged or fill 

material] makes its way downstream,” post, at 22 (citation omitted). 

See also post, at 17 (opinion of KENNEDY, J.). By contrast, amici cite 

multiple empirical analyses that contradict the dissent’s philological 

approach to sediment erosion—including one which concludes that 

“[t]he idea that the discharge of dredged or fill material into isolated 

waters, ephemeral drains or non-tidal ditches will pollute navigable 

waters located any appreciable distance from them lacks credibility.” 

R. Pierce, Technical Principles Related to Establishing the Limits of 

Jurisdiction for Section 404 of the Clean Water Act 34–40 (Apr. 2003), 

available at www.wetlandtraining.com/tpreljscwa.pdf, cited in Brief for 

International Council of Shopping Centers et al. as Amici Curiae 26–27; 

Brief for Pulte Homes, Inc., et al. as Amici Curiae 20–21; Brief for 

Foundation for Environmental and Economic Progress et al. as Amici 

Curiae 29, and n. 53 (“Fill material does not migrate”). Such scientific 

analysis is entirely unnecessary, however, to reach the unremarkable 

conclusion that the deposit of mobile pollutants into upstream ephemeral channels is naturally described as an “addition . . . to navigable 

waters,” 33 U. S. C. §1362(12), while the deposit of stationary fill 

material generally is not. 
Cite as: 547 U. S. ____ (2006) 27 

Opinion of SCALIA, J. 

tional “waters.” See Tr. of Oral Arg. 57. But, as noted 

above, the lower courts do not generally rely on characterization of intervening channels as “waters of the United 

States” in applying §1311 to the traditional pollutants

subject to §1342. Moreover, the proof of downstream flow 

of pollutants required under §1342 appears substantially

similar, if not identical, to the proof of a hydrologic connection that would be required, on the Sixth Circuit’s theory 

of jurisdiction, to prove that an upstream channel or wetland is a “wate[r] of the United States.” See Rapanos II, 

376 F. 3d, at 639. Compare, e.g., App. to Pet. for Cert. in

No. 04–1034, at B11, B20, B26 (testimony of hydrologic

connections based on observation of surface water connections), with Southview Farm, supra, at 118–121 (testimony of discharges based on observation of the flow of 

polluted water). In either case, the agency must prove 

that the contaminant-laden waters ultimately reach covered waters. 

Finally, respondents and many amici admonish that 

narrowing the definition of “the waters of the United

States” will hamper federal efforts to preserve the Nation’s

wetlands. It is not clear that the state and local conservation efforts that the CWA explicitly calls for, see 33

U. S. C. §1251(b), are in any way inadequate for the goal 

of preservation. In any event, a Comprehensive National 

Wetlands Protection Act is not before us, and the 

“wis[dom]” of such a statute, post, at 19 (opinion of STEVENS, J.), is beyond our ken. What is clear, however, is 

that Congress did not enact one when it granted the Corps 

jurisdiction over only “the waters of the United States.” 

VI 

In an opinion long on praise of environmental protection

and notably short on analysis of the statutory text and 

structure, the dissent would hold that “the waters of the 

United States” include any wetlands “adjacent” (no matter 
28 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

how broadly defined) to “tributaries” (again, no matter 

how broadly defined) of traditional navigable waters. For 

legal support of its policy-laden conclusion, the dissent

relies exclusively on two sources: “[o]ur unanimous opinion in Riverside Bayview,” post, at 6; and “Congress’ deliberate acquiescence in the Corps’ regulations in 1977,” post, 

at 11. Each of these is demonstrably inadequate to support the apparently limitless scope that the dissent would

permit the Corps to give to the Act. 

A 

The dissent’s assertion that Riverside Bayview “squarely 

controls these cases,” post, at 6, is wholly implausible. 

First, Riverside Bayview could not possibly support the 

dissent’s acceptance of the Corps’ inclusion of dry beds as 

“tributaries,” post, at 19, because the definition of tributaries was not at issue in that case. Riverside Bayview addressed only the Act’s inclusion of wetlands abutting

navigable-in-fact waters, and said nothing at all about 

what non-navigable tributaries the Act might also cover. 

Riverside Bayview likewise provides no support for the

dissent’s complacent acceptance of the Corps’ definition of

“adjacent,” which (as noted above) has been extended

beyond reason to include, inter alia, the 100-year floodplain of covered waters. See supra, at 9. The dissent 

notes that Riverside Bayview quoted without comment the

Corps’ description of “adjacent” wetlands as those “that

form the border of or are in reasonable proximity to other 

waters of the United States.” Post, at 8 (citing 474 U. S., 

at 134 (quoting 42 Fed. Reg. 37128)). As we have already

discussed, this quotation provides no support for the inclusion of physically unconnected wetlands as covered “waters.” See supra, at 22–23, n. 10. The dissent relies principally on a footnote in Riverside Bayview recognizing that 

“‘not every adjacent wetland is of great importance to the

environment of adjoining bodies of water,’” and that all 
Cite as: 547 U. S. ____ (2006) 29 

Opinion of SCALIA, J. 

“‘adjacent’” wetlands are nevertheless covered by the Act, 

post, at 8 (quoting 474 U. S., at 135, n. 9). Of course, this 

footnote says nothing to support the dissent’s broad definition of “adjacent”—quite the contrary, the quoted sentence

uses “adjacent” and “adjoining” interchangeably, and the 

footnote qualifies a sentence holding that the wetland was

covered “[b]ecause” it “actually abut[ted] on a navigable 

waterway.” Id., at 135 (emphasis added). Moreover, that 

footnote’s assertion that the Act may be interpreted to 

include even those adjoining wetlands that are “lacking in

importance to the aquatic environment,” id., at 135, n. 9, 

confirms that the scope of ambiguity of “the waters of the

United States” is determined by a wetland’s physical connection to covered waters, not its ecological relationship 

thereto. 

The dissent reasons (1) that Riverside Bayview held that 

“the waters of the United States” include “adjacent wetlands,” and (2) we must defer to the Corps’ interpretation 

of the ambiguous word “adjacent.” Post, at 20–21. But 

this is mere legerdemain. The phrase “adjacent wetlands”

is not part of the statutory definition that the Corps is

authorized to interpret, which refers only to “the waters of

the United States,” 33 U. S. C. §1362(7).12 In expounding 

the term “adjacent” as used in Riverside Bayview, we are 

explaining our own prior use of that word to interpret the

definitional phrase “the waters of the United States.” 

—————— 

12Nor does the passing reference to “wetlands adjacent thereto” in 

§1344(g)(1) purport to expand that statutory definition. As the dissent 

concedes, post, at 20, that reference merely confirms that the statutory

definition can be read to include some wetlands—namely, those that 

directly “abut” covered waters. Riverside Bayview explicitly acknowledged that §1344(g)(1) “does not conclusively determine the construction to be placed on the use of the term ‘waters’ elsewhere in the Act 

(particularly in [§1362(7)], which contains the relevant definition of 

‘navigable waters’); however, . . . it does at least suggest strongly that 

the term ‘waters’ as used in the Act does not necessarily exclude ‘wetlands.’ ” 474 U. S., at 138, n. 11 (emphases added). 
30 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

However ambiguous the term may be in the abstract, as 

we have explained earlier, “adjacent” as used in Riverside 

Bayview is not ambiguous between “physically abutting” 

and merely “nearby.” See supra, at 21–23. 

The dissent would distinguish SWANCC on the ground

that it “had nothing to say about wetlands,” post, at 9— 

i.e., it concerned “isolated ponds” rather than isolated 

wetlands. This is the ultimate distinction without a difference. If isolated “permanent and seasonal ponds of 

varying size . . . and depth,” 531 U. S., at 163—which,

after all, might at least be described as “waters” in their

own right—did not constitute “waters of the United 

States,” a fortiori, isolated swampy lands do not constitute 

“waters of the United States.” See also 474 U. S., at 132. 

As the author of today’s dissent has written, “[i]f, as I

believe, actually navigable waters lie at the very heart of 

Congress’ commerce power and ‘isolated,’ nonnavigable 

waters lie closer to . . . the margin, ‘isolated wetlands,’ 

which are themselves only marginally ‘waters,’ are the

most marginal category of ‘waters of the United States’ 

potentially covered by the statute.” 531 U. S., at 187, 

n. 13 (STEVENS, J., dissenting).

The only other ground that the dissent offers to distinguish SWANCC is that, unlike the ponds in SWANCC, the 

wetlands in these cases are “adjacent to navigable bodies

of water and their tributaries”—where “adjacent” may be

interpreted who-knows-how broadly. It is not clear why

roughly defined physical proximity should make such a

difference—without actual abutment, it raises no boundary-drawing ambiguity, and it is undoubtedly a poor proxy 

for ecological significance. In fact, though the dissent is

careful to restrict its discussion to wetlands “adjacent” to

tributaries, its reasons for including those wetlands are

strictly ecological—such wetlands would be included because they “serve . . . important water quality roles,” post, 

at 11, and “play important roles in the watershed,” post, at 
Cite as: 547 U. S. ____ (2006) 31 

Opinion of SCALIA, J. 

18–19. This reasoning would swiftly overwhelm SWANCC 

altogether; after all, the ponds at issue in SWANCC could, 

no less than the wetlands in these cases, “offer ‘nesting,

spawning, rearing and resting sites for aquatic or land 

species,’” and “‘serve as valuable storage areas for storm

and flood waters,’” post, at 9–10. The dissent’s exclusive 

focus on ecological factors, combined with its total deference 

to the Corps’ ecological judgments, would permit the Corps

to regulate the entire country as “waters of the United 

States.” 

B 

Absent a plausible ground in our case law for its sweeping position, the dissent relies heavily on “Congress’ deliberate acquiescence in the Corps’ regulations in 1977,” post, 

at 11—noting that “[w]e found [this acquiescence] significant in Riverside Bayview,” and even “acknowledged in 

SWANCC” that we had done so, post, at 12. SWANCC 

“acknowledged” that Riverside Bayview had relied on 

congressional acquiescence only to criticize that reliance.

It reasserted in no uncertain terms our oft-expressed 

skepticism towards reading the tea leaves of congressional 

inaction: 

“Although we have recognized congressional acquiescence to administrative interpretations of a statute in

some situations, we have done so with extreme care. 

Failed legislative proposals are a particularly dangerous ground on which to rest an interpretation of a 

prior statute. . . . The relationship between the actions 

and inactions of the 95th Congress and the intent of

the 92d Congress in passing [§1344(a)] is also considerably attenuated. Because subsequent history is less 

illuminating than the contemporaneous evidence, respondents face a difficult task in overcoming the plain

text and import of [§1344(a)].” 531 U. S., at 169 (citations, internal quotation marks, and footnote omitted). 
32 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

Congress takes no governmental action except by legislation. What the dissent refers to as “Congress’ deliberate 

acquiescence” should more appropriately be called Congress’s failure to express any opinion. We have no idea 

whether the Members’ failure to act in 1977 was attributable to their belief that the Corps’ regulations were correct, or rather to their belief that the courts would eliminate any excesses, or indeed simply to their unwillingness 

to confront the environmental lobby. To be sure, we have 

sometimes relied on congressional acquiescence when 

there is evidence that Congress considered and rejected

the “precise issue” presented before the Court, Bob Jones 

Univ. v. United States, 461 U. S. 574, 600 (1983) (emphasis added). However, “[a]bsent such overwhelming evidence of acquiescence, we are loath to replace the plain

text and original understanding of a statute with an

amended agency interpretation.” SWANCC, supra, at 169, 

n. 5 (emphasis added).

The dissent falls far short of producing “overwhelming

evidence” that Congress considered and failed to act upon 

the “precise issue” before the Court today—namely, what

constitutes an “adjacent” wetland covered by the Act.

Citing Riverside Bayview’s account of the 1977 debates, 

the dissent claims nothing more than that Congress “conducted extensive debates about the Corps’ regulatory

jurisdiction over wetlands [and] rejected efforts to limit

that jurisdiction . . . .” Post, at 11. In fact, even that 

vague description goes too far. As recounted in Riverside 

Bayview, the 1977 debates concerned a proposal to “limi[t] 

the Corps’ authority under [§1344] to waters navigable in

fact and their adjacent wetlands (defined as wetlands

periodically inundated by contiguous navigable waters),” 

474 U. S., at 136. In rejecting this proposal, Congress

merely failed to enact a limitation of “waters” to include

only navigable-in-fact waters—an interpretation we affirmatively reject today, see supra, at 12—and a definition 
Cite as: 547 U. S. ____ (2006) 33 

Opinion of SCALIA, J. 

of wetlands based on “periodi[c] inundat[ion]” that appears

almost nowhere in the briefs or opinions of these cases.13 

No plausible interpretation of this legislative inaction can 

construe it as an implied endorsement of every jot and 

tittle of the Corps’ 1977 regulations. In fact, Riverside 

Bayview itself relied on this legislative inaction only as “at 

least some evidence of the reasonableness” of the agency’s

inclusion of adjacent wetlands under the Act, 474 U. S., at

137, and for the observation that “even those who would 

have restricted the reach of the Corps’ jurisdiction” would

not have excised adjacent wetlands, ibid. Both of these 

—————— 

13The sole exception is in JUSTICE KENNEDY’s opinion, which argues

that Riverside Bayview rejected our physical-connection requirement by 

accepting as a given that any wetland formed by inundation from 

covered waters (whether or not continuously connected to them) is

covered by the Act: “The Court in Riverside Bayview . . . did not suggest 

that a flood-based origin would not support jurisdiction; indeed, it 

presumed the opposite. See 474 U. S., at 134 (noting that the Corps’ 

view was valid ‘even for wetlands that are not the result of flooding or

permeation’ (emphasis added)).” Post, at 16. Of course JUSTICE 

KENNEDY himself fails to observe this supposed presumption, since his 

“significant nexus” test makes no exception for wetlands created by 

inundation. In any event, the language from Riverside Bayview in 

JUSTICE KENNEDY’s parenthetical is wrenched out of context. The 

sentence which JUSTICE KENNEDY quotes in part immediately followed

the Court’s conclusion that “adjacent” wetlands are included because of 

“the inherent difficulties of defining precise bounds to regulable waters,” 474 U. S., at 134. And the full sentence reads as follows: “This 

holds true even for wetlands that are not the result of flooding or 

permeation by water having its source in adjacent bodies of open 

water,” ibid. (emphasis added). Clearly, the “wetlands” referred to in

the sentence are only “adjacent” wetlands—namely, those with the 

continuous physical connection that the rest of the Riverside Bayview 

opinion required, see supra, at 21–23. Thus, it is evident that the 

quoted language was not at all a rejection of the physical-connection

requirement, but rather a rejection of the alternative position (which

had been adopted by the lower court in that case, see id., at 125) that 

the only covered wetlands are those created by inundation. As long as 

the wetland is “adjacent” to covered waters, said Riverside Bayview, its 

creation vel non by inundation is irrelevant. 
34 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

conclusions are perfectly consistent with our interpretation, and neither illuminates the disputed question of 

what constitutes an “adjacent” wetland. 

C 

In a curious appeal to entrenched Executive error, the

dissent contends that “the appropriateness of the Corps’ 

30-year implementation of the Clean Water Act should be

addressed to Congress or the Corps rather than to the 

Judiciary.” Post, at 14; see also post, at 2, 22. Surely this

is a novel principle of administrative law—a sort of 30-

year adverse possession that insulates disregard of statutory text from judicial review. It deservedly has no precedent in our jurisprudence. We did not invoke such a principle in SWANCC, when we invalidated one aspect of the

Corps’ implementation. 

The dissent contends that “[b]ecause there is ambiguity 

in the phrase ‘waters of the United States’ and because 

interpreting it broadly to cover such ditches and streams

advances the purpose of the Act, the Corps’ approach 

should command our deference.” Post, at 19. Two defects 

in a single sentence: “[W]aters of the United States” is in 

some respects ambiguous. The scope of that ambiguity,

however, does not conceivably extend to whether storm 

drains and dry ditches are “waters,” and hence does not 

support the Corps’ interpretation. And as for advancing

“the purpose of the Act”: We have often criticized that last

resort of extravagant interpretation, noting that no law

pursues its purpose at all costs, and that the textual limitations upon a law’s scope are no less a part of its “purpose” than its substantive authorizations. See, e.g., Director, Office of Workers’ Compensation Programs v. Newport 

News Shipbuilding & Dry Dock Co., 514 U. S. 122, 135– 

136 (1995).

Finally, we could not agree more with the dissent’s 

statement, post, at 14, that “[w]hether the benefits of 
Cite as: 547 U. S. ____ (2006) 35 

Opinion of SCALIA, J. 

particular conservation measures outweigh their costs is a

classic question of public policy that should not be answered by appointed judges.” Neither, however, should it 

be answered by appointed officers of the Corps of Engineers in contradiction of congressional direction. It is the 

dissent’s opinion, and not ours, which appeals not to a

reasonable interpretation of enacted text, but to the great 

environmental benefits that a patently unreasonable 

interpretation can achieve. We have begun our discussion

by mentioning, to be sure, the high costs imposed by that 

interpretation—but they are in no way the basis for our

decision, which rests, plainly and simply, upon the limited 

meaning that can be borne by the phrase “waters of the 

United States.” 

VII 

JUSTICE KENNEDY’s opinion concludes that our reading

of the Act “is inconsistent with its text, structure, and 

purpose.” Post, at 19. His own opinion, however, leaves

the Act’s “text” and “structure” virtually unaddressed, and 

rests its case upon an interpretation of the phrase “significant nexus,” ibid., which appears in one of our opinions. 

To begin with, JUSTICE KENNEDY’s reading of “significant nexus” bears no easily recognizable relation to either

the case that used it (SWANCC) or to the earlier case that 

that case purported to be interpreting (Riverside Bayview). 

To establish a “significant nexus,” JUSTICE KENNEDY 

would require the Corps to “establish . . . on a case-by-case

basis” that wetlands adjacent to nonnavigable tributaries 

“significantly affect the chemical, physical, and biological 

integrity of other covered waters more readily understood

as ‘navigable.’” Post, at 25, 23. This standard certainly

does not come from Riverside Bayview, which explicitly

rejected such case-by-case determinations of ecological 

significance for the jurisdictional question whether a

wetland is covered, holding instead that all physically 
36 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

connected wetlands are covered. 474 U. S., at 135, n. 9. It 

is true enough that one reason for accepting that physicalconnection criterion was the likelihood that a physically

connected wetland would have an ecological effect upon

the adjacent waters. But case-by-case determination of 

ecological effect was not the test. Likewise, that test cannot be derived from SWANCC’s characterization of Riverside Bayview, which emphasized that the wetlands which 

possessed a “significant nexus” in that earlier case “actually abutted on a navigable waterway,” 531 U. S., at 167, 

and which specifically rejected the argument that physically unconnected ponds could be included based on their 

ecological connection to covered waters. In fact, JUSTICE 

KENNEDY acknowledges that neither Riverside Bayview 

nor SWANCC required, for wetlands abutting navigablein-fact waters, the case-by-case ecological determination 

that he proposes for wetlands that neighbor nonnavigable 

tributaries. See post, at 23. Thus, JUSTICE KENNEDY 

misreads SWANCC’s “significant nexus” statement as

mischaracterizing Riverside Bayview to adopt a case-bycase test of ecological significance; and then transfers that 

standard to a context that Riverside Bayview expressly

declined to address (namely, wetlands nearby nonnavigable tributaries); while all the time conceding that 

this standard does not apply in the context that Riverside 

Bayview did address (wetlands abutting navigable waterways). Truly, this is “turtles all the way down.”14 

—————— 

14The allusion is to a classic story told in different forms and attributed to various authors. See, e.g., Geertz, Thick Description: Toward 

an Interpretive Theory of Culture, in The Interpretation of Cultures

28–29 (1973). In our favored version, an Eastern guru affirms that the 

earth is supported on the back of a tiger. When asked what supports

the tiger, he says it stands upon an elephant; and when asked what 

supports the elephant he says it is a giant turtle. When asked, finally,

what supports the giant turtle, he is briefly taken aback, but quickly

replies “Ah, after that it is turtles all the way down.” 
Cite as: 547 U. S. ____ (2006) 37 

Opinion of SCALIA, J. 

But misreading our prior decisions is not the principal

problem. The principal problem is reading them in utter 

isolation from the text of the Act. One would think, after 

reading JUSTICE KENNEDY’s exegesis, that the crucial

provision of the text of the CWA was a jurisdictional requirement of “significant nexus” between wetlands and 

navigable waters. In fact, however, that phrase appears 

nowhere in the Act, but is taken from SWANCC’s cryptic 

characterization of the holding of Riverside Bayview. Our 

interpretation of the phrase is both consistent with those 

opinions and compatible with what the Act does establish 

as the jurisdictional criterion: “waters of the United 

States.” Wetlands are “waters of the United States” if 

they bear the “significant nexus” of physical connection,

which makes them as a practical matter indistinguishable 

from waters of the United States. What other nexus could 

conceivably cause them to be “waters of the United 

States”? JUSTICE KENNEDY’s test is that they, “either

alone or in combination with similarly situated lands in 

the region, significantly affect the chemical, physical, and

biological integrity of other covered waters more readily

understood as ‘navigable,’” post, at 23 (emphasis added).

But what possible linguistic usage would accept that 

whatever (alone or in combination) affects waters of the 

United States is waters of the United States? 

Only by ignoring the text of the statute and by assuming 

that the phrase of SWANCC (“significant nexus”) can 

properly be interpreted in isolation from that text does

JUSTICE KENNEDY reach the conclusion he has arrived at. 

Instead of limiting its meaning by reference to the text it 

was applying, he purports to do so by reference to what he 

calls the “purpose” of the statute. Its purpose is to clean

up the waters of the United States, and therefore anything 

that might “significantly affect” the purity of those waters

bears a “significant nexus” to those waters, and thus (he

never says this, but the text of the statute demands that 
38 RAPANOS v. UNITED STATES 

Opinion of SCALIA, J. 

he mean it) is those waters. This is the familiar tactic of 

substituting the purpose of the statute for its text, freeing

the Court to write a different statute that achieves the 

same purpose. To begin with, as we have discussed earlier, clean water is not the only purpose of the statute. So 

is the preservation of primary state responsibility for 

ordinary land-use decisions. 33 U. S. C. §1251(b).

JUSTICE KENNEDY’s test takes no account of this purpose.

More fundamentally, however, the test simply rewrites the

statute, using for that purpose the gimmick of “significant

nexus.” It would have been an easy matter for Congress to 

give the Corps jurisdiction over all wetlands (or, for that

matter, all dry lands) that “significantly affect the chemical, physical, and biological integrity of” waters of the

United States. It did not do that, but instead explicitly 

limited jurisdiction to “waters of the United States.” 

JUSTICE KENNEDY’s disposition would disallow some of 

the Corps’ excesses, and in that respect is a more moderate flouting of statutory command than JUSTICE 

STEVENS’.15 In another respect, however, it is more extreme. At least JUSTICE STEVENS can blame his implausible reading of the statute upon the Corps. His error con-

—————— 

15 It is unclear how much more moderate the flouting is, since JUSTICE 

KENNEDY’s “significant nexus” standard is perfectly opaque. When, 

exactly, does a wetland “significantly affect” covered waters, and when 

are its effects “in contrast . . . speculative or insubstantial”? Post, at 23. 

JUSTICE KENNEDY does not tell us clearly—except to suggest, post, at 

25, that “ ‘ “isolated” is generally a matter of degree’ ” (quoting Leibowitz & Nadeau, Isolated Wetlands: State-of-the-Science and Future 

Directions, 23 Wetlands 663, 669 (2003)). As the dissent hopefully 

observes, post, at 24, such an unverifiable standard is not likely to 

constrain an agency whose disregard for the statutory language has

been so long manifested. In fact, by stating that “[i]n both the consolidated cases before the Court the record contains evidence suggesting

the possible existence of a significant nexus according to the principles 

outlined above,” post, at 26, JUSTICE KENNEDY tips a wink at the 

agency, inviting it to try its same expansive reading again. 
Cite as: 547 U. S. ____ (2006) 39 

Opinion of SCALIA, J. 

sists of giving that agency more deference than reason 

permits. JUSTICE KENNEDY, however, has devised his new 

statute all on his own. It purports to be, not a grudging 

acceptance of an agency’s close-to-the-edge expansion of its 

own powers, but rather the most reasonable interpretation 

of the law. It is far from that, unless whatever affects 

waters is waters. 

VIII 

Because the Sixth Circuit applied the wrong standard to

determine if these wetlands are covered “waters of the 

United States,” and because of the paucity of the record in

both of these cases, the lower courts should determine, in 

the first instance, whether the ditches or drains near each 

wetland are “waters” in the ordinary sense of containing a 

relatively permanent flow; and (if they are) whether the 

wetlands in question are “adjacent” to these “waters” in

the sense of possessing a continuous surface connection

that creates the boundary-drawing problem we addressed 

in Riverside Bayview. 

* * * 

We vacate the judgments of the Sixth Circuit in both 

No. 04–1034 and No. 04–1384, and remand both cases for 

further proceedings. 

It is so ordered. 
_________________ 

_________________ 

Cite as: 547 U. S. ____ (2006) 1 

ROBERTS, C. J., concurring 

SUPREME COURT OF THE UNITED STATES 

Nos. 04–1034 and 04–1384 

JOHN A. RAPANOS, ET UX., ET AL., PETITIONERS 

04–1034 v. 

UNITED STATES 

JUNE CARABELL ET AL., PETITIONERS 

04–1384 v. 

UNITED STATES ARMY CORPS OF ENGINEERS ET AL. 

ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF 

APPEALS FOR THE SIXTH CIRCUIT 

[June 19, 2006] 

CHIEF JUSTICE ROBERTS, concurring. 

Five years ago, this Court rejected the position of the

Army Corps of Engineers on the scope of its authority to

regulate wetlands under the Clean Water Act, 86 Stat. 

816, as amended, 33 U. S. C. §1251 et seq. Solid Waste 

Agency of Northern Cook Cty. v. Army Corps of Engineers, 

531 U. S. 159 (2001) (SWANCC). The Corps had taken the 

view that its authority was essentially limitless; this 

Court explained that such a boundless view was inconsistent with the limiting terms Congress had used in the Act. 

Id., at 167–174. 

In response to the SWANCC decision, the Corps and the

Environmental Protection Agency (EPA) initiated a rulemaking to consider “issues associated with the scope of 

waters that are subject to the Clean Water Act (CWA), in 

light of the U. S. Supreme Court decision in [SWANCC].” 

68 Fed. Reg. 1991 (2003). The “goal of the agencies” was

“to develop proposed regulations that will further the

public interest by clarifying what waters are subject to 
2 RAPANOS v. UNITED STATES 

ROBERTS, C. J., concurring 

CWA jurisdiction and affording full protection to these 

waters through an appropriate focus of Federal and State 

resources consistent with the CWA.” Ibid. 

Agencies delegated rulemaking authority under a statute such as the Clean Water Act are afforded generous

leeway by the courts in interpreting the statute they are

entrusted to administer. See Chevron U. S. A. Inc. v. Natural Resources Defense Council, Inc., 467 U. S. 837, 842–845 

(1984). Given the broad, somewhat ambiguous, but nonetheless clearly limiting terms Congress employed in the 

Clean Water Act, the Corps and the EPA would have enjoyed plenty of room to operate in developing some notion of 

an outer bound to the reach of their authority. 

The proposed rulemaking went nowhere. Rather than 

refining its view of its authority in light of our decision in 

SWANCC, and providing guidance meriting deference under

our generous standards, the Corps chose to adhere to its

essentially boundless view of the scope of its power. The 

upshot today is another defeat for the agency. 

It is unfortunate that no opinion commands a majority of

the Court on precisely how to read Congress’ limits on the 

reach of the Clean Water Act. Lower courts and regulated

entities will now have to feel their way on a case-by-case

basis. This situation is certainly not unprecedented. See 

Grutter v. Bollinger, 539 U. S. 306, 325 (2003) (discussing 

Marks v. United States, 430 U. S. 188 (1977)). What is 

unusual in this instance, perhaps, is how readily the situation could have been avoided.* 

—————— 

*The scope of the proposed rulemaking was not as narrow as JUSTICE 

STEVENS suggests, post, at 10, n. 4 (dissenting opinion). See 68 Fed. 

Reg. 1994 (2003) (“Additionally, we invite your views as to whether any 

other revisions are needed to the existing regulations on which waters 

are jurisdictional under the CWA”); id., at 1992 (“Today’s [notice of

proposed rulemaking] seeks public input on what, if any, revisions in 

light of SWANCC might be appropriate to the regulations that define

‘waters of the U. S.’, and today’s [notice] thus would be of interest to all 
Cite as: 547 U. S. ____ (2006) 3 

ROBERTS, C. J., concurring 

—————— 

entities discharging to, or regulating, such waters” (emphases added)).

The agencies can decide for themselves whether, as the SWANCC 

dissenter suggests, it was wise for them to take no action in response to

SWANCC. 
_________________ 

_________________ 

Cite as: 547 U. S. ____ (2006) 1 

KENNEDY, J., concurring in judgment 

SUPREME COURT OF THE UNITED STATES 

Nos. 04–1034 and 04–1384 

JOHN A. RAPANOS, ET UX., ET AL., PETITIONERS 

04–1034 v. 

UNITED STATES 

JUNE CARABELL ET AL., PETITIONERS 

04–1384 v. 

UNITED STATES ARMY CORPS OF ENGINEERS ET AL. 

ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF 

APPEALS FOR THE SIXTH CIRCUIT 

[June 19, 2006] 

JUSTICE KENNEDY, concurring in the judgment. 

These consolidated cases require the Court to decide 

whether the term “navigable waters” in the Clean Water 

Act extends to wetlands that do not contain and are not 

adjacent to waters that are navigable in fact. In Solid 

Waste Agency of Northern Cook Cty. v. Army Corps of Engineers, 531 U. S. 159 (2001) (SWANCC), the Court held, 

under the circumstances presented there, that to constitute “‘navigable waters’” under the Act, a water or wetland must possess a “significant nexus” to waters that are 

or were navigable in fact or that could reasonably be so 

made. Id., at 167, 172. In the instant cases neither the 

plurality opinion nor the dissent by JUSTICE STEVENS 

chooses to apply this test; and though the Court of Appeals 

recognized the test’s applicability, it did not consider all 

the factors necessary to determine whether the lands in 
2 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

question had, or did not have, the requisite nexus. In my

view the cases ought to be remanded to the Court of Appeals for proper consideration of the nexus requirement. 

I 

Although both the plurality opinion and the dissent by 

JUSTICE STEVENS (hereinafter the dissent) discuss the

background of these cases in some detail, a further discussion of the relevant statutes, regulations, and facts may

clarify the analysis suggested here. 

A 

The “objective” of the Clean Water Act (Act), is “to restore

and maintain the chemical, physical, and biological integrity of the Nation’s waters.” 33 U. S. C. §1251(a). To that 

end, the statute, among other things, prohibits “the discharge of any pollutant by any person” except as provided

in the Act. §1311(a). As relevant here, the term “discharge

of a pollutant” means “any addition of any pollutant to

navigable waters from any point source.” §1362(12). The 

term “pollutant” is defined as “dredged spoil, solid waste, 

incinerator residue, sewage, garbage, sewage sludge, munitions, chemical wastes, biological materials, radioactive

materials, heat, wrecked or discarded equipment, rock, 

sand, cellar dirt and industrial, municipal, and agricultural

waste discharged into water.” §1362(6). The Secretary of 

the Army, acting through the Chief of Engineers of the

Army Corps of Engineers, may issue permits for “discharge

of dredged or fill material into the navigable waters at

specified disposal sites.” §§1344(a), (c), (d); but see §1344(f) 

(categorically exempting certain forms of “discharge of 

dredged or fill material” from regulation under §1311(a)). 

Pursuant to §1344(g), States with qualifying programs may 

assume certain aspects of the Corps’ permitting responsibility. Apart from dredged or fill material, pollutant discharges require a permit from the Environmental Protec-
Cite as: 547 U. S. ____ (2006) 3 

KENNEDY, J., concurring in judgment 

tion Agency (EPA), which also oversees the Corps’ (and 

qualifying States’) permitting decisions. See §§1311(a), 

1342(a), 1344(c). Discharge of pollutants without an appropriate permit may result in civil or criminal liability. See 

§1319.

The statutory term to be interpreted and applied in the

two instant cases is the term “navigable waters.” The 

outcome turns on whether that phrase reasonably describes certain Michigan wetlands the Corps seeks to 

regulate. Under the Act “[t]he term ‘navigable waters’ 

means the waters of the United States, including the 

territorial seas.” §1362(7). In a regulation the Corps has 

construed the term “waters of the United States” to include not only waters susceptible to use in interstate

commerce—the traditional understanding of the term 

“navigable waters of the United States,” see, e.g., United 

States v. Appalachian Elec. Power Co., 311 U. S. 377, 406– 

408 (1940); The Daniel Ball, 10 Wall. 557, 563–564 (1871)—

but also tributaries of those waters and, of particular relevance here, wetlands adjacent to those waters or their tributaries. 33 CFR §§328.3(a)(1), (5), (7) (2005). The Corps 

views tributaries as within its jurisdiction if they carry a 

perceptible “ordinary high water mark.” §328.4(c); 65 Fed. 

Reg. 12823 (2000). An ordinary high-water mark is a “line

on the shore established by the fluctuations of water and 

indicated by physical characteristics such as clear, natural

line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, the 

presence of litter and debris, or other appropriate means 

that consider the characteristics of the surrounding areas.” 33 CFR §328.3(e).

Contrary to the plurality’s description, ante, at 2–3, 15, 

wetlands are not simply moist patches of earth. They are 

defined as “those areas that are inundated or saturated by

surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do 
4 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

support, a prevalence of vegetation typically adapted for life

in saturated soil conditions. Wetlands generally include

swamps, marshes, bogs, and similar areas.” §328.3(b). The 

Corps’ Wetlands Delineation Manual, including over 100 

pages of technical guidance for Corps officers, interprets 

this definition of wetlands to require: (1) prevalence of plant 

species typically adapted to saturated soil conditions, determined in accordance with the United States Fish and 

Wildlife Service’s National List of Plant Species that Occur 

in Wetlands; (2) hydric soil, meaning soil that is saturated, 

flooded, or ponded for sufficient time during the growing

season to become anaerobic, or lacking in oxygen, in the 

upper part; and (3) wetland hydrology, a term generally 

requiring continuous inundation or saturation to the surface during at least five percent of the growing season in 

most years. See Wetlands Research Program Technical 

Report Y–87–1 (on-line edition), pp. 12–34 (Jan. 1987), 

http://www.saj.usace.army.mil/permit/documents/87manual

.pdf (all Internet material as visited June 16, 2006, and

available in Clerk of Court’s case file). Under the Corps’ 

regulations, wetlands are adjacent to tributaries, and thus

covered by the Act, even if they are “separated from other 

waters of the United States by man-made dikes or barriers,

natural river berms, beach dunes and the like.” §328.3(c). 

B 

The first consolidated case before the Court, Rapanos v. 

United States, No. 04–1034, relates to a civil enforcement 

action initiated by the United States in the United States 

District Court for the Eastern District of Michigan against 

the owners of three land parcels near Midland, Michigan.

The first parcel, known as the Salzburg site, consists of 

roughly 230 acres. The District Court, applying the Corps’ 

definition of wetlands, found based on expert testimony 

that the Salzburg site included 28 acres of wetlands. The 

District Court further found that “the Salzburg wetlands 
Cite as: 547 U. S. ____ (2006) 5 

KENNEDY, J., concurring in judgment 

have a surface water connection to tributaries of the 

Kawkawlin River which, in turn, flows into the Saginaw

River and ultimately into Lake Huron.” App. to Pet. for 

Cert. B11. Water from the site evidently spills into the

Hoppler Drain, located just north of the property, which 

carries water into the Hoppler Creek and thence into the 

Kawkawlin River, which is navigable. A state official 

testified that he observed carp spawning in a ditch just 

north of the property, indicating a direct surface-water 

connection from the ditch to the Saginaw Bay of Lake 

Huron. 

The second parcel, known as the Hines Road site, consists of 275 acres, which the District Court found included 

64 acres of wetlands. The court found that the wetlands 

have a surface-water connection to the Rose Drain, which 

carries water into the Tittabawassee River, a navigable 

waterway. The final parcel, called the Pine River site, 

consists of some 200 acres. The District Court found that 

49 acres were wetlands and that a surface water connection linked the wetlands to the nearby Pine River, which 

flows into Lake Huron. 

At all relevant times, John Rapanos owned the Salzburg 

site; a company he controlled owned the Hines Road site; 

and Rapanos’ wife and a company she controlled (possibly 

in connection with another entity) owned the Pine River 

site. All these parties are petitioners here. In December 

1988, Mr. Rapanos, hoping to construct a shopping center, 

asked the Michigan Department of Natural Resources to 

inspect the Salzburg site. A state official informed Rapanos that while the site likely included regulated wetlands, Rapanos could proceed with the project if the wetlands were delineated (that is, identified and preserved) or 

if a permit were obtained. Pursuing the delineation option, Rapanos hired a wetlands consultant to survey the 

property. The results evidently displeased Rapanos:

Informed that the site included between 48 and 58 acres of 
6 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

wetlands, Rapanos allegedly threatened to “destroy” the 

consultant unless he eradicated all traces of his report. 

Rapanos then ordered $350,000-worth of earthmoving and 

landclearing work that filled in 22 of the 64 wetlands 

acres on the Salzburg site. He did so without a permit and 

despite receiving cease-and-desist orders from state officials and the EPA. At the Hines Road and Pine River 

sites, construction work—again conducted in violation of

state and federal compliance orders—altered an additional

17 and 15 wetlands acres, respectively.

The Federal Government brought criminal charges

against Rapanos. In the suit at issue here, however, the 

United States alleged civil violations of the Clean Water

Act against all the Rapanos petitioners. Specifically, the

Government claimed that petitioners discharged fill into

jurisdictional wetlands, failed to respond to requests for 

information, and ignored administrative compliance orders. See 33 U. S. C. §§1311(a), 1318(a), 1319(a). After a 

13-day bench trial, the District Court made the findings

noted earlier and, on that basis, upheld the Corps’ jurisdiction over wetlands on the three parcels. On the merits 

the court ruled in the Government’s favor, finding that

violations occurred at all three sites. As to two other sites, 

however, the court rejected the Corps’ claim to jurisdiction, holding that the Government had failed to carry its

burden of proving the existence of wetlands under the 

three-part regulatory definition. (These two parcels are no

longer at issue.) The United States Court of Appeals for 

the Sixth Circuit affirmed. 376 F. 3d 629, 634 (2004). 

This Court granted certiorari to consider the Corps’ jurisdiction over wetlands on the Salzburg, Hines Road, and 

Pine River sites. 546 U. S. ___ (2005). 

The second consolidated case, Carabell, No. 04–1384, 

involves a parcel shaped like a right triangle and consisting of some 19.6 acres, 15.9 of which are forested wetlands. 257 F. Supp. 2d 917, 923 (ED Mich. 2003). The 
Cite as: 547 U. S. ____ (2006) 7 

KENNEDY, J., concurring in judgment 

property is located roughly one mile from Lake St. Clair, a 

430-square-mile lake located between Michigan and Canada that is popular for boating and fishing and produces

some 48 percent of the sport fish caught in the Great 

Lakes, see Brief for Macomb County, Michigan as Amicus 

Curiae 2. The right-angle corner of the property is located

to the northwest. The hypotenuse, which runs from northeast to southwest, lies alongside a man-made berm that

separates the property from a ditch. At least under current conditions—that is, without the deposit of fill in the 

wetlands that the landowners propose—the berm ordinarily, if not always, blocks surface-water flow from the wetlands into the ditch. But cf. App. 186a (administrative

hearing testimony by consultant for Carabells indicating

“you would start seeing some overflow” in a “ten year

storm”). Near the northeast corner of the property, the 

ditch connects with the Sutherland-Oemig Drain, which

carries water continuously throughout the year and empties into Auvase Creek. The creek in turn empties into 

Lake St. Clair. At its southwest end, the ditch connects to 

other ditches that empty into the Auvase Creek and 

thence into Lake St. Clair. 

In 1993 petitioners Keith and June Carabell sought a 

permit from the Michigan Department of Environmental 

Quality (MDEQ), which has assumed permitting functions 

of the Corps pursuant to §1344(g). Petitioners hoped to fill

in the wetlands and construct 130 condominium units. 

Although the MDEQ denied the permit, a State Administrative Law Judge directed the agency to approve an

alternative plan, proposed by the Carabells, that involved 

the construction of 112 units. This proposal called for

filling in 12.2 acres of the property while creating retention ponds on 3.74 acres. Because the EPA had objected to 

the permit, jurisdiction over the case transferred to the

Corps. See §1344(j).

The Corps’ district office concluded that the Carabells’ 
8 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

property “provides water storage functions that, if destroyed, could result in an increased risk of erosion and 

degradation of water quality in the Sutherland-Oemig 

Drain, Auvase Creek, and Lake St. Clair.” Id., at 127a. 

The district office denied the permit, and the Corps upheld 

the denial in an administrative appeal. The Carabells, 

challenging both the Corps’ jurisdiction and the merits of 

the permit denial, sought judicial review pursuant to the

Administrative Procedure Act, 5 U. S. C. §706(2)(A). The 

United States District Court for the Eastern District of 

Michigan granted summary judgment to the Corps, 257 

F. Supp. 2d 917, and the United States Court of Appeals 

for the Sixth Circuit affirmed, 391 F. 3d 704 (2005). This 

Court granted certiorari to consider the jurisdictional

question. 546 U. S. ___ (2005). 

II 

Twice before the Court has construed the term “navigable

waters” in the Clean Water Act. In United States v. Riverside Bayview Homes, Inc., 474 U. S. 121 (1985), the Court 

upheld the Corps’ jurisdiction over wetlands adjacent to 

navigable-in-fact waterways. Id., at 139. The property in 

Riverside Bayview, like the wetlands in the Carabell case 

now before the Court, was located roughly one mile from

Lake St. Clair, see United States v. Riverside Bayview 

Homes, Inc., 729 F. 2d 391, 392 (CA6 1984) (decision on 

review in Riverside Bayview), though in that case, unlike 

Carabell, the lands at issue formed part of a wetland that

directly abutted a navigable-in-fact creek, 474 U. S., at 131.

In regulatory provisions that remain in effect, the Corps

had concluded that wetlands perform important functions

such as filtering and purifying water draining into adjacent

water bodies, 33 CFR §320.4(b)(2)(vii), slowing the flow of

runoff into lakes, rivers, and streams so as to prevent flooding and erosion, §§320.4(b)(2)(iv), (v), and providing critical 

habitat for aquatic animal species, §320.4(b)(2)(i). 474 
Cite as: 547 U. S. ____ (2006) 9 

KENNEDY, J., concurring in judgment 

U. S., at 134–135. Recognizing that “[a]n agency’s construction of a statute it is charged with enforcing is entitled to

deference if it is reasonable and not in conflict with the 

expressed intent of Congress,” id., at 131 (citing Chemical 

Mfrs. Assn. v. Natural Resources Defense Council, Inc., 470 

U. S. 116, 125 (1985), and Chevron U. S. A. Inc. v. Natural 

Resources Defense Council, Inc., 467 U. S. 837, 842–845 

(1984)), the Court held that “the Corps’ ecological judgment

about the relationship between waters and their adjacent

wetlands provides an adequate basis for a legal judgment

that adjacent wetlands may be defined as waters under the 

Act,” 474 U. S., at 134. The Court reserved, however, the 

question of the Corps’ authority to regulate wetlands other 

than those adjacent to open waters. See id., at 131–132, 

n. 8. 

In SWANCC, the Court considered the validity of the

Corps’ jurisdiction over ponds and mudflats that were

isolated in the sense of being unconnected to other waters 

covered by the Act. 531 U. S., at 171. The property at

issue was an abandoned sand and gravel pit mining operation where “remnant excavation trenches” had “evolv[ed] 

into a scattering of permanent and seasonal ponds.” Id., 

at 163. Asserting jurisdiction pursuant to a regulation

called the “Migratory Bird Rule,” the Corps argued that

these isolated ponds were “waters of the United States”

(and thus “navigable waters” under the Act) because they

were used as habitat by migratory birds. Id., at 164–165. 

The Court rejected this theory. “It was the significant

nexus between wetlands and ‘navigable waters,’ ” the 

Court held, “that informed our reading of the [Act] in 

Riverside Bayview Homes.” Id., at 167. Because such a 

nexus was lacking with respect to isolated ponds, the 

Court held that the plain text of the statute did not permit

the Corps’ action. Id., at 172. 

Riverside Bayview and SWANCC establish the framework for the inquiry in the cases now before the Court: Do 
10 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

the Corps’ regulations, as applied to the wetlands in Carabell and the three wetlands parcels in Rapanos, constitute 

a reasonable interpretation of “navigable waters” as in 

Riverside Bayview or an invalid construction as in 

SWANCC? Taken together these cases establish that in 

some instances, as exemplified by Riverside Bayview, the 

connection between a nonnavigable water or wetland and

a navigable water may be so close, or potentially so close, 

that the Corps may deem the water or wetland a “navigable water” under the Act. In other instances, as exemplified by SWANCC, there may be little or no connection.

Absent a significant nexus, jurisdiction under the Act is

lacking. Because neither the plurality nor the dissent

addresses the nexus requirement, this separate opinion, in

my respectful view, is necessary. 

A 

The plurality’s opinion begins from a correct premise.

As the plurality points out, and as Riverside Bayview

holds, in enacting the Clean Water Act Congress intended

to regulate at least some waters that are not navigable in

the traditional sense. Ante, at 12; Riverside Bayview, 474 

U. S., at 133; see also SWANCC, supra, at 167. This 

conclusion is supported by “the evident breadth of congressional concern for protection of water quality and 

aquatic ecosystems.” Riverside Bayview, supra, at 133; see 

also Milwaukee v. Illinois, 451 U. S. 304, 318 (1981) (describing the Act as “an all-encompassing program of water 

pollution regulation”). It is further compelled by statutory 

text, for the text is explicit in extending the coverage of the

Act to some nonnavigable waters. In a provision allowing 

States to assume some regulatory functions of the Corps 

(an option Michigan has exercised), the Act limits States 

to issuing permits for: 

“the discharge of dredged or fill material into the 

navigable waters (other than those waters which are 
Cite as: 547 U. S. ____ (2006) 11 

KENNEDY, J., concurring in judgment 

presently used, or are susceptible to use in their natural condition or by reasonable improvement as a

means to transport interstate or foreign commerce 

shoreward to their ordinary high water mark, including all waters which are subject to the ebb and flow of 

the tide shoreward to their ordinary high water mark,

or mean higher high water mark on the west coast,

including wetlands adjacent thereto) within its jurisdiction.” 33 U. S. C. §1344(g)(1). 

Were there no Clean Water Act “navigable waters” apart 

from waters “presently used” or “susceptible to use” in interstate commerce, the “other than” clause, which begins the 

long parenthetical statement, would overtake the delegation

of authority the provision makes at the outset. Congress, it

follows, must have intended a broader meaning for navigable 

waters. The mention of wetlands in the “other than” clause, 

moreover, makes plain that at least some wetlands fall 

within the scope of the term “navigable waters.” See Riverside Bayview, supra, at 138–139, and n. 11. 

From this reasonable beginning the plurality proceeds

to impose two limitations on the Act; but these limitations, 

it is here submitted, are without support in the language

and purposes of the Act or in our cases interpreting it. 

First, because the dictionary defines “waters” to mean

“water ‘[a]s found in streams and bodies forming geographical features such as oceans, rivers, [and] lakes,’ or 

‘the flowing or moving masses, as of waves or floods, making up such streams or bodies,” ante, at 13 (quoting Webster’s New International Dictionary 2882 (2d ed. 1954) 

(hereinafter Webster’s Second)), the plurality would conclude that the phrase “navigable waters” permits Corps

and EPA jurisdiction only over “relatively permanent,

standing or flowing bodies of water,” ante, at 13–14—a 

category that in the plurality’s view includes “seasonal”

rivers, that is, rivers that carry water continuously except 
12 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

during “dry months,” but not intermittent or ephemeral 

streams, ante, at 13–15, and n. 5. Second, the plurality 

asserts that wetlands fall within the Act only if they bear

“a continuous surface connection to bodies that are ‘waters 

of the United States’ in their own right”—waters, that is,

that satisfy the plurality’s requirement of permanent

standing water or continuous flow. Ante, at 23–24. 

The plurality’s first requirement—permanent standing

water or continuous flow, at least for a period of “some 

months,” ante, at 13–14, and n. 5—makes little practical

sense in a statute concerned with downstream water 

quality. The merest trickle, if continuous, would count as 

a “water” subject to federal regulation, while torrents

thundering at irregular intervals through otherwise dry 

channels would not. Though the plurality seems to presume that such irregular flows are too insignificant to be

of concern in a statute focused on “waters,” that may not 

always be true. Areas in the western parts of the Nation 

provide some examples. The Los Angeles River, for instance, ordinarily carries only a trickle of water and often 

looks more like a dry roadway than a river. See, e.g., B. 

Gumprecht, The Los Angeles River: Its Life, Death, and

Possible Rebirth 1–2 (1999); Martinez, City of Angels’ 

Signature River Tapped for Rebirth, Chicago Tribune, 

Apr. 10, 2005, section 1, p. 8. Yet it periodically releases

water-volumes so powerful and destructive that it has 

been encased in concrete and steel over a length of some 

50 miles. See Gumprecht, supra, at 227. Though this

particular waterway might satisfy the plurality’s test, it is 

illustrative of what often-dry watercourses can become 

when rain waters flow. See, e.g., County of Los Angeles 

Dept. of Public Works, Water Resources Division: 

2002–2003 Hydrologic Report, Runoff, Daily Discharge, 

F377–R BOUQUET CANYON CREEK at Urbandale 

Avenue 11107860 Bouquet Creek Near Saugus, 

CA, http://ladpw.org/wrd/report/0203/runoff/discharge.cfm 
Cite as: 547 U. S. ____ (2006) 13 

KENNEDY, J., concurring in judgment 

(indicating creek carried no flow for much of the year but

carried 122 cubic feet per second on Feb. 12, 2003). 

To be sure, Congress could draw a line to exclude irregular waterways, but nothing in the statute suggests it has 

done so. Quite the opposite, a full reading of the dictionary definition precludes the plurality’s emphasis on permanence: The term “waters” may mean “flood or inundation,” Webster’s Second 2882, events that are 

impermanent by definition. Thus, although of course the

Act’s use of the adjective “navigable” indicates a focus on 

waterways rather than floods, Congress’ use of “waters”

instead of “water,” ante, at 13, does not necessarily carry 

the connotation of “relatively permanent, standing or

flowing bodies of water,” ante, at 13–14. (And contrary to

the plurality’s suggestion, ante, at 13, n. 4, there is no 

indication in the dictionary that the “flood or inundation”

definition is limited to poetry.) In any event, even granting the plurality’s preferred definition—that “waters” 

means “water ‘[a]s found in streams and bodies forming 

geographical features such as oceans, rivers, [and] lakes,’” 

ante, at 13 (quoting Webster’s Second 2882)—the dissent

is correct to observe that an intermittent flow can constitute a stream, in the sense of “ ‘a current or course of 

water or other fluid, flowing on the earth,’” ante, at 14, 

n. 6 (quoting Webster’s Second 2493), while it is flowing. 

See post, at 15–16 (STEVENS, J., dissenting) (also noting 

Court’s use of the phrase “‘intermittent stream’” in Harrisonville v. W. S. Dickey Clay Mfg. Co., 289 U. S. 334, 335 

(1933)). It follows that the Corps can reasonably interpret 

the Act to cover the paths of such impermanent streams. 

Apart from the dictionary, the plurality invokes Riverside Bayview to support its interpretation that the term

“waters” is so confined, but this reliance is misplaced. To 

be sure, the Court there compared wetlands to “rivers, 

streams, and other hydrographic features more conventionally identifiable as ‘waters.’ ” 474 U. S., at 131. It is 
14 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

quite a stretch to claim, however, that this mention of 

hydrographic features “echoe[s]” the dictionary’s reference 

to “‘geographical features such as oceans, rivers, [and] 

lakes.’” Ante, at 16 (quoting Webster’s Second 2882). In 

fact the Riverside Bayview opinion does not cite the dictionary definition on which the plurality relies, and the 

phrase “hydrographic features” could just as well refer to

intermittent streams carrying substantial flow to navigable waters. See Webster’s Second 1221 (defining “hydrography” as “[t]he description and study of seas, lakes,

rivers, and other waters; specif[ically] . . . [t]he measurement of flow and investigation of the behavior of streams, 

esp[ecially] with reference to the control or utilization of 

their waters”). 

Also incorrect is the plurality’s attempt to draw support

from the statutory definition of “point source” as “any

discernible, confined and discrete conveyance, including 

but not limited to any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, or vessel or other floating 

craft, from which pollutants are or may be discharged.” 33 

U. S. C. §1362(14). This definition is central to the Act’s 

regulatory structure, for the term “discharge of a pollutant” is defined in relevant part to mean “any addition of 

any pollutant to navigable waters from any point source,”

§1362(12). Interpreting the point-source definition, the

plurality presumes, first, that the point-source examples 

describe “watercourses through which intermittent waters 

typically flow,” and second, that point sources and navigable waters are “separate and distinct categories.” Ante, at 

17. From this the plurality concludes, by a sort of negative inference, that navigable waters may not be intermittent. The conclusion is unsound. Nothing in the pointsource definition requires an intermittent flow. Polluted 

water could flow night and day from a pipe, channel, or 

conduit and yet still qualify as a point source; any con-
Cite as: 547 U. S. ____ (2006) 15 

KENNEDY, J., concurring in judgment 

trary conclusion would likely exclude, among other things,

effluent streams from sewage treatment plants. As a 

result, even were the statute read to require continuity of 

flow for navigable waters, certain water-bodies could

conceivably constitute both a point source and a water. At 

any rate, as the dissent observes, the fact that point

sources may carry continuous flow undermines the plurality’s conclusion that covered “waters” under the Act may

not be discontinuous. See post, at 17. 

The plurality’s second limitation—exclusion of wetlands

lacking a continuous surface connection to other jurisdictional waters—is also unpersuasive. To begin with, the 

plurality is wrong to suggest that wetlands are “indistinguishable” from waters to which they bear a surface connection. Ante, at 37. Even if the precise boundary may be

imprecise, a bog or swamp is different from a river. The 

question is what circumstances permit a bog, swamp, or 

other nonnavigable wetland to constitute a “navigable 

water” under the Act—as §1344(g)(1), if nothing else, 

indicates is sometimes possible, see supra, at 10–11. 

Riverside Bayview addressed that question and its answer 

is inconsistent with the plurality’s theory. There, in upholding the Corps’ authority to regulate “wetlands adjacent to other bodies of water over which the Corps has 

jurisdiction,” the Court deemed it irrelevant whether “the

moisture creating the wetlands . . . find[s] its source in the 

adjacent bodies of water.” 474 U. S., at 135. The Court 

further observed that adjacency could serve as a valid 

basis for regulation even as to “wetlands that are not 

significantly intertwined with the ecosystem of adjacent 

waterways.” Id., at 135, n. 9. “If it is reasonable,” the 

Court explained, “for the Corps to conclude that in the

majority of cases, adjacent wetlands have significant

effects on water quality and the aquatic ecosystem, its

definition can stand.” Ibid. 

The Court in Riverside Bayview did note, it is true, the 
16 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

difficulty of defining where “water ends and land begins,” 

id., at 132, and the Court cited that problem as one reason 

for deferring to the Corps’ view that adjacent wetlands 

could constitute waters. Given, however, the further 

recognition in Riverside Bayview that an overinclusive 

definition is permissible even when it reaches wetlands

holding moisture disconnected from adjacent water-bodies, 

id., at 135, and n. 9, Riverside Bayview’s observations 

about the difficulty of defining the water’s edge cannot be 

taken to establish that when a clear boundary is evident,

wetlands beyond the boundary fall outside the Corps’ 

jurisdiction.

For the same reason Riverside Bayview also cannot be 

read as rejecting only the proposition, accepted by the 

Court of Appeals in that case, that wetlands covered by

the Act must contain moisture originating in neighboring 

waterways. See id., at 125, 134. Since the Court of Appeals had accepted that theory, the Court naturally addressed it. Yet to view the decision’s reasoning as limited 

to that issue—an interpretation the plurality urges here, 

ante, at 33, n. 13—would again overlook the opinion’s

broader focus on wetlands’ “significant effects on water

quality and the aquatic ecosystem,” 474 U. S., at 135, n. 9. 

In any event, even were this reading of Riverside Bayview

correct, it would offer no support for the plurality’s proposed requirement of a “continuous surface connection,” 

ante, at 23. The Court in Riverside Bayview rejected the 

proposition that origination in flooding was necessary for 

jurisdiction over wetlands. It did not suggest that a floodbased origin would not support jurisdiction; indeed, it

presumed the opposite. See 474 U. S., at 134 (noting that 

the Corps’ view was valid “even for wetlands that are not 

the result of flooding or permeation” (emphasis added)). 

Needless to say, a continuous connection is not necessary

for moisture in wetlands to result from flooding—the 

connection might well exist only during floods. 
Cite as: 547 U. S. ____ (2006) 17 

KENNEDY, J., concurring in judgment 

SWANCC, likewise, does not support the plurality’s 

surface-connection requirement. SWANCC’s holding that

“nonnavigable, isolated, intrastate waters,” 531 U. S., at 171,

are not “navigable waters” is not an explicit or implicit

overruling of Riverside Bayview’s approval of adjacency as

a factor in determining the Corps’ jurisdiction. In rejecting the Corps’ claimed authority over the isolated ponds in 

SWANCC, the Court distinguished adjacent nonnavigable

waters such as the wetlands addressed in Riverside Bayview. 531 U. S., at 167, 170–171.

 As Riverside Bayview recognizes, the Corps’ adjacency

standard is reasonable in some of its applications. Indeed, 

the Corps’ view draws support from the structure of the 

Act, while the plurality’s surface-water-connection requirement does not.

As discussed above, the Act’s prohibition on the discharge of pollutants into navigable waters, 33 U. S. C. 

§1311(a), covers both the discharge of toxic materials such 

as sewage, chemical waste, biological material, and radioactive material and the discharge of dredged spoil, rock, 

sand, cellar dirt, and the like. All these substances are 

defined as pollutants whose discharge into navigable 

waters violates the Act. §§1311(a), 1362(6), (12). One 

reason for the parallel treatment may be that the discharge of fill material can impair downstream water quality. The plurality argues otherwise, asserting that

dredged or fill material “does not normally wash downstream.” Ante, at 26. As the dissent points out, this 

proposition seems questionable as an empirical matter.

See post, at 22. It seems plausible that new or loose fill, 

not anchored by grass or roots from other vegetation, could 

travel downstream through waterways adjacent to a wetland; at the least this is a factual possibility that the

Corps’ experts can better assess than can the plurality. 

Silt, whether from natural or human sources, is a major 

factor in aquatic environments, and it may clog water-
18 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

ways, alter ecosystems, and limit the useful life of dams.

See, e.g., Fountain, Unloved, But Not Unbuilt, N. Y. 

Times, June 5, 2005 section 4, p. 3, col. 1; DePalma, Dam 

to Be Demolished to Save an Endangered Species, N. Y. 

Times, Apr. 26, 2004, section B, p. 1, col. 2; MacDougall, 

Damage Can Be Irreversible, Los Angeles Times, June 19, 

1987, pt. 1, p. 10, col. 4.

Even granting, however, the plurality’s assumption that

fill material will stay put, Congress’ parallel treatment of

fill material and toxic pollution may serve another purpose. As the Court noted in Riverside Bayview, “the Corps

has concluded that wetlands may serve to filter and purify 

water draining into adjacent bodies of water, 33 CFR

§320.4(b)(2)(vii) (1985), and to slow the flow of surface 

runoff into lakes, rivers, and streams and thus prevent 

flooding and erosion, see §§320.4(b)(2)(iv) and (v).” 474 

U. S., at 134. Where wetlands perform these filtering and 

runoff-control functions, filling them may increase downstream pollution, much as a discharge of toxic pollutants

would. Not only will dirty water no longer be stored and 

filtered but also the act of filling and draining itself may 

cause the release of nutrients, toxins, and pathogens that

were trapped, neutralized, and perhaps amenable to filtering or detoxification in the wetlands. See U. S. Congress, 

Office of Technology Assessment, Wetlands: Their Use 

and Regulation, OTA–O–206 pp. 43, 48–52 (Mar. 1984), 

http://govinfo.library.unt.edu/ota/OTA_4/DATA/1984/8433

.pdf (hereinafter OTA). In many cases, moreover, filling in 

wetlands separated from another water by a berm can 

mean that flood water, impurities, or runoff that would

have been stored or contained in the wetlands will instead 

flow out to major waterways. With these concerns in 

mind, the Corps’ definition of adjacency is a reasonable 

one, for it may be the absence of an interchange of waters

prior to the dredge and fill activity that makes protection

of the wetlands critical to the statutory scheme. 
Cite as: 547 U. S. ____ (2006) 19 

KENNEDY, J., concurring in judgment 

In sum the plurality’s opinion is inconsistent with the

Act’s text, structure, and purpose. As a fallback the plurality suggests that avoidance canons would compel its

reading even if the text were unclear. Ante, at 18–20. In 

SWANCC, as one reason for rejecting the Corps’ assertion 

of jurisdiction over the isolated ponds at issue there, the

Court observed that this “application of [the Corps’] regulations” would raise significant questions of Commerce

Clause authority and encroach on traditional state landuse regulation. 531 U. S., at 174. As SWANCC observed, 

ibid., and as the plurality points out here, ante, at 18, the 

Act states that “[i]t is the policy of the Congress to recognize, preserve, and protect the primary responsibilities and 

rights of States to prevent, reduce, and eliminate pollution,

[and] to plan the development and use . . . of land and water 

resources,” 33 U. S. C. §1251(b). The Court in SWANCC 

cited this provision as evidence that a clear statement supporting jurisdiction in applications raising constitutional 

and federalism difficulties was lacking. 531 U. S., at 174.

The concerns addressed in SWANCC do not support the 

plurality’s interpretation of the Act. In SWANCC, by interpreting the Act to require a significant nexus with navigable waters, the Court avoided applications—those involving waters without a significant nexus—that appeared 

likely, as a category, to raise constitutional difficulties and

federalism concerns. Here, in contrast, the plurality’s 

interpretation does not fit the avoidance concerns it raises. 

On the one hand, when a surface-water connection is 

lacking, the plurality forecloses jurisdiction over wetlands 

that abut navigable-in-fact waters—even though such 

navigable waters were traditionally subject to federal 

authority. On the other hand, by saying the Act covers

wetlands (however remote) possessing a surface-water

connection with a continuously flowing stream (however

small), the plurality’s reading would permit applications of 

the statute as far from traditional federal authority as are 
20 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

the waters it deems beyond the statute’s reach. Even 

assuming, then, that federal regulation of remote wetlands and nonnavigable waterways would raise a difficult 

Comerce Clause issue notwithstanding those waters’ 

aggregate effects on national water quality, but cf. 

Wickard v. Filburn, 317 U. S. 111 (1942); see also infra, at 

25–26, the plurality’s reading is not responsive to this 

concern. As for States’ “responsibilities and rights,”

§1251(b), it is noteworthy that 33 States plus the District of 

Columbia have filed an amici brief in this litigation asserting that the Clean Water Act is important to their own

water policies. See Brief for States of New York et al. 1–3. 

These amici note, among other things, that the Act protects

downstream States from out-of-state pollution that they 

cannot themselves regulate. Ibid. 

It bears mention also that the plurality’s overall tone 

and approach—from the characterization of acres of wetlands destruction as “backfilling . . . wet fields,” ante, at 2, 

to the rejection of Corps authority over “man-made drainage ditches” and “dry arroyos” without regard to how

much water they periodically carry, ante, at 15, to the 

suggestion, seemingly contrary to Congress’ judgment, 

that discharge of fill material is inconsequential for adjacent waterways, ante, at 26, and n. 11—seems unduly 

dismissive of the interests asserted by the United States

in these cases. Important public interests are served by 

the Clean Water Act in general and by the protection of 

wetlands in particular. To give just one example, amici 

here have noted that nutrient-rich runoff from the Mississippi River has created a hypoxic, or oxygen-depleted,

“dead zone” in the Gulf of Mexico that at times approaches

the size of Massachusetts and New Jersey. Brief for Association of State Wetland Managers et al. 21–23; Brief for 

Environmental Law Institute 23. Scientific evidence 

indicates that wetlands play a critical role in controlling 

and filtering runoff. See, e.g., OTA 43, 48–52; R. Tiner, In 
Cite as: 547 U. S. ____ (2006) 21 

KENNEDY, J., concurring in judgment 

Search of Swampland: A Wetland Sourcebook and Field 

Guide 93–95 (2d ed. 2005); Whitmire & Hamilton, Rapid 

Removal of Nitrate and Sulfate in Freshwater Wetland 

Sediments, 34 J. Env. Quality 2062 (2005). It is true, as 

the plurality indicates, that environmental concerns provide no reason to disregard limits in the statutory text, 

ante, at 27, but in my view the plurality’s opinion is not a

correct reading of the text. The limits the plurality would 

impose, moreover, give insufficient deference to Congress’ 

purposes in enacting the Clean Water Act and to the 

authority of the Executive to implement that statutory 

mandate. 

Finally, it should go without saying that because the 

plurality presents its interpretation of the Act as the only

permissible reading of the plain text, ante, at 20, 23–24, 

the Corps would lack discretion, under the plurality’s

theory, to adopt contrary regulations. THE CHIEF JUSTICE 

suggests that if the Corps and EPA had issued new regulations after SWANCC they would have “enjoyed plenty of

room to operate in developing some notion of an outer 

bound to the reach of their authority” and thus could have 

avoided litigation of the issues we address today. Ante, at 

2. That would not necessarily be true under the opinion 

THE CHIEF JUSTICE has joined. New rulemaking could

have averted the disagreement here only if the Corps had 

anticipated the unprecedented reading of the Act that the

plurality advances. 

B 

While the plurality reads nonexistent requirements into

the Act, the dissent reads a central requirement out—

namely, the requirement that the word “navigable” in

“navigable waters” be given some importance. Although

the Court has held that the statute’s language invokes

Congress’ traditional authority over waters navigable in 

fact or susceptible of being made so, SWANCC, 531 U. S., 
22 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

at 172 (citing Appalachian Power, 311 U. S., at 407–408), 

the dissent would permit federal regulation whenever

wetlands lie alongside a ditch or drain, however remote 

and insubstantial, that eventually may flow into traditional navigable waters. The deference owed to the Corps’

interpretation of the statute does not extend so far. 

Congress’ choice of words creates difficulties, for the Act

contemplates regulation of certain “navigable waters” that

are not in fact navigable. Supra, at 10–11. Nevertheless, 

the word “navigable” in the Act must be given some effect.

See SWANCC, supra, at 172. Thus, in SWANCC the 

Court rejected the Corps’ assertion of jurisdiction over

isolated ponds and mudflats bearing no evident connection 

to navigable-in-fact waters. And in Riverside Bayview, 

while the Court indicated that “the term ‘navigable’ as 

used in the Act is of limited import,” 474 U. S., at 133, it

relied, in upholding jurisdiction, on the Corps’ judgment

that “wetlands adjacent to lakes, rivers, streams, and 

other bodies of water may function as integral parts of the 

aquatic environment even when the moisture creating the 

wetlands does not find its source in the adjacent bodies of

water,” id., at 135. The implication, of course, was that 

wetlands’ status as “integral parts of the aquatic environment”—that is, their significant nexus with navigable 

waters—was what established the Corps’ jurisdiction over

them as waters of the United States. 

 Consistent with SWANCC and Riverside Bayview and 

with the need to give the term “navigable” some meaning,

the Corps’ jurisdiction over wetlands depends upon the 

existence of a significant nexus between the wetlands in

question and navigable waters in the traditional sense. 

The required nexus must be assessed in terms of the 

statute’s goals and purposes. Congress enacted the law to

“restore and maintain the chemical, physical, and biological integrity of the Nation’s waters,” 33 U. S. C. §1251(a), 

and it pursued that objective by restricting dumping and 
Cite as: 547 U. S. ____ (2006) 23 

KENNEDY, J., concurring in judgment 

filling in “navigable waters,” §§1311(a), 1362(12). With 

respect to wetlands, the rationale for Clean Water Act

regulation is, as the Corps has recognized, that wetlands 

can perform critical functions related to the integrity of

other waters—functions such as pollutant trapping, flood

control, and runoff storage. 33 CFR §320.4(b)(2). Accordingly, wetlands possess the requisite nexus, and thus come

within the statutory phrase “navigable waters,” if the

wetlands, either alone or in combination with similarly

situated lands in the region, significantly affect the chemical, physical, and biological integrity of other covered

waters more readily understood as “navigable.” When, in 

contrast, wetlands’ effects on water quality are speculative 

or insubstantial, they fall outside the zone fairly encompassed by the statutory term “navigable waters.”

Although the dissent acknowledges that wetlands’ ecological functions vis-à-vis other covered waters are the 

basis for the Corps’ regulation of them, post, at 10–11, it 

concludes that the ambiguity in the phrase “navigable 

waters” allows the Corps to construe the statute as reaching all “non-isolated wetlands,” just as it construed the Act

to reach the wetlands adjacent to navigable-in-fact waters

in Riverside Bayview, see post, at 11. This, though, seems

incorrect. The Corps’ theory of jurisdiction in these consolidated cases—adjacency to tributaries, however remote

and insubstantial—raises concerns that go beyond the

holding of Riverside Bayview; and so the Corps’ assertion

of jurisdiction cannot rest on that case.

As applied to wetlands adjacent to navigable-in-fact 

waters, the Corps’ conclusive standard for jurisdiction 

rests upon a reasonable inference of ecologic interconnection, and the assertion of jurisdiction for those wetlands is 

sustainable under the Act by showing adjacency alone. 

That is the holding of Riverside Bayview. Furthermore, 

although the Riverside Bayview Court reserved the question of the Corps’ authority over “wetlands that are not 
24 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

adjacent to bodies of open water,” 474 U. S., at 131–132, 

n. 8, and in any event addressed no factual situation other 

than wetlands adjacent to navigable-in-fact waters, it may 

well be the case that Riverside Bayview’s reasoning—

supporting jurisdiction without any inquiry beyond adjacency—could apply equally to wetlands adjacent to certain

major tributaries. Through regulations or adjudication, 

the Corps may choose to identify categories of tributaries 

that, due to their volume of flow (either annually or on

average), their proximity to navigable waters, or other 

relevant considerations, are significant enough that wetlands adjacent to them are likely, in the majority of cases,

to perform important functions for an aquatic system

incorporating navigable waters. 

The Corps’ existing standard for tributaries, however, 

provides no such assurance. As noted earlier, the Corps

deems a water a tributary if it feeds into a traditional 

navigable water (or a tributary thereof) and possesses an 

ordinary high-water mark, defined as a “line on the shore

established by the fluctuations of water and indicated by

[certain] physical characteristics,” §328.3(e). See supra, at 

3. This standard presumably provides a rough measure 

of the volume and regularity of flow. Assuming it is

subject to reasonably consistent application, but see U. S.

General Accounting Office, Report to the Chairman,

Subcommittee on Energy Policy, Natural Resources and

Regulating Affairs, Committee on Reform, House of 

Representatives, Waters and Wetlands: Corps of Engineers Needs to Evaluate Its District Office Practices in 

Determining Jurisdiction, GAO–04–297 pp. 3–4 (Feb.

2004), http://www.gao.gov/new.items/d04297.pdf (noting

variation in results among Corps district offices), it may 

well provide a reasonable measure of whether specific 

minor tributaries bear a sufficient nexus with other regulated waters to constitute “navigable waters” under the

Act. Yet the breadth of this standard—which seems to 
Cite as: 547 U. S. ____ (2006) 25 

KENNEDY, J., concurring in judgment 

leave wide room for regulation of drains, ditches, and

streams remote from any navigable-in-fact water and

carrying only minor water-volumes towards it—precludes

its adoption as the determinative measure of whether

adjacent wetlands are likely to play an important role in 

the integrity of an aquatic system comprising navigable 

waters as traditionally understood. Indeed, in many cases

wetlands adjacent to tributaries covered by this standard 

might appear little more related to navigable-in-fact waters than were the isolated ponds held to fall beyond the 

Act’s scope in SWANCC. Cf. Leibowitz & Nadeau, Isolated 

Wetlands: State-of-the-Science and Future Directions, 23 

Wetlands 663, 669 (2003) (noting that “‘isolated’ is generally a matter of degree”).

When the Corps seeks to regulate wetlands adjacent to

navigable-in-fact waters, it may rely on adjacency to establish its jurisdiction. Absent more specific regulations,

however, the Corps must establish a significant nexus on a

case-by-case basis when it seeks to regulate wetlands

based on adjacency to nonnavigable tributaries. Given the 

potential overbreadth of the Corps’ regulations, this showing is necessary to avoid unreasonable applications of the 

statute. Where an adequate nexus is established for a

particular wetland, it may be permissible, as a matter of

administrative convenience or necessity, to presume covered status for other comparable wetlands in the region. 

That issue, however, is neither raised by these facts nor

addressed by any agency regulation that accommodates 

the nexus requirement outlined here. 

This interpretation of the Act does not raise federalism 

or Commerce Clause concerns sufficient to support a 

presumption against its adoption. To be sure, the significant nexus requirement may not align perfectly with the 

traditional extent of federal authority. Yet in most cases 

regulation of wetlands that are adjacent to tributaries and 

possess a significant nexus with navigable waters will 
26 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

raise no serious constitutional or federalism difficulty. Cf. 

Pierce County v. Guillen, 537 U. S. 129, 147 (2003) (upholding federal legislation “aimed at improving safety in

the channels of commerce”); Oklahoma ex rel. Phillips v. 

Guy F. Atkinson Co., 313 U. S. 508, 524–525 (1941) 

(“[J]ust as control over the non-navigable parts of a river 

may be essential or desirable in the interests of the navigable portions, so may the key to flood control on a navigable stream be found in whole or in part in flood control 

on its tributaries . . . . [T]he exercise of the granted power 

of Congress to regulate interstate commerce may be aided 

by appropriate and needful control of activities and agencies which, though intrastate, affect that commerce”). As 

explained earlier, moreover, and as exemplified by 

SWANCC, the significant-nexus test itself prevents problematic applications of the statute. See supra, at 19–20; 

531 U. S., at 174. The possibility of legitimate Commerce 

Clause and federalism concerns in some circumstances 

does not require the adoption of an interpretation that

departs in all cases from the Act’s text and structure. See 

Gonzales v. Raich, 545 U. S. 1, __ (2005) (slip op., at 14) 

(“[W]hen a general regulatory statute bears a substantial 

relation to commerce, the de minimis character of individual instances arising under that statute is of no consequence” (internal quotation marks omitted)). 

III 

In both the consolidated cases before the Court the 

record contains evidence suggesting the possible existence 

of a significant nexus according to the principles outlined 

above. Thus the end result in these cases and many others to be considered by the Corps may be the same as that 

suggested by the dissent, namely, that the Corps’ assertion of jurisdiction is valid. Given, however, that neither 

the agency nor the reviewing courts properly considered

the issue, a remand is appropriate, in my view, for appli-
Cite as: 547 U. S. ____ (2006) 27 

KENNEDY, J., concurring in judgment 

cation of the controlling legal standard. 

Rapanos 

As the dissent points out, in Rapanos, No. 04–1034, an 

expert whom the District Court found “eminently qualified” and “highly credible,” App. to Pet. for Cert. B7, testified that the wetlands were providing “habitat, sediment 

trapping, nutrient recycling, and flood peak diminution,

reduction flow water augmentation.” 4 Tr. 96 (Apr. 5, 

1999). Although the expert had “not studied the upstream

drainage of these sites” and thus could not assert that the 

wetlands were performing important pollutant-trapping 

functions, ibid., he did observe: 

“we have a situation in which the flood water attenuation in that water is held on the site in the wetland 

. . . such that it does not add to flood peak. By the

same token it would have some additional water flowing into the rivers during the drier periods, thus, increasing the low water flow. . . . By the same token on

all of the sites to the extent that they slow the flow of

water off of the site they will also accumulate sediment and thus trap sediment and hold nutrients for 

use in those wetlands systems later in the season as

well.” Id., at 95–96. 

In addition, in assessing the hydrology prong of the threepart wetlands test, see supra, at 3–4, the District Court 

made extensive findings regarding water tables and 

drainage on the parcels at issue. In applying the Corps’ 

jurisdictional regulations, the District Court found that

each of the wetlands bore surface water connections to 

tributaries of navigable-in-fact waters. 

Much the same evidence should permit the establishment of a significant nexus with navigable-in-fact waters, 

particularly if supplemented by further evidence about the

significance of the tributaries to which the wetlands are 
28 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

connected. The Court of Appeals, however, though recognizing that under SWANCC such a nexus was required for

jurisdiction, held that a significant nexus “can be satisfied 

by the presence of a hydrologic connection.” 376 F. 3d, at 

639. Absent some measure of the significance of the connection for downstream water quality, this standard was

too uncertain. Under the analysis described earlier, 

supra, at 22–23, 25, mere hydrologic connection should not 

suffice in all cases; the connection may be too insubstantial for the hydrologic linkage to establish the required

nexus with navigable waters as traditionally understood. 

In my view this case should be remanded so that the

District Court may reconsider the evidence in light of the 

appropriate standard. See, e.g., Pullman-Standard v. 

Swint, 456 U. S. 273, 291 (1982) (“When an appellate court 

discerns that a district court has failed to make a finding 

because of an erroneous view of the law, the usual rule is 

that there should be a remand for further proceedings to

permit the trial court to make the missing findings”). 

Carabell 

In Carabell, No. 04–1384, the record also contains evidence bearing on the jurisdictional inquiry. The Corps

noted in deciding the administrative appeal that “[b]esides

the effects on wildlife habitat and water quality, the [district office] also noted that the project would have a major, 

long-term detrimental effect on wetlands, flood retention, 

recreation and conservation and overall ecology,” App. 

218a. Similarly, in the district office’s permit evaluation, 

Corps officers observed: 

“The proposed work would destroy/adversely impact

an area that retains rainfall and forest nutrients and 

would replace it with a new source area for runoff pollutants. Pollutants from this area may include lawn

fertilizers, herbicides, pesticides, road salt, oil, and 

grease. These pollutants would then runoff directly 
Cite as: 547 U. S. ____ (2006) 29 

KENNEDY, J., concurring in judgment 

into the waterway. . . . Overall, the operation and use

of the proposed activity would have a major, long 

term, negative impact on water quality. The cumulative impacts of numerous such projects would be major and negative as the few remaining wetlands in the 

area are developed.” Id., at 97a–98a. 

The Corps’ evaluation further noted that by “eliminat[ing] 

the potential ability of the wetland to act as a sediment

catch basin,” the proposed project “would contribute to

increased runoff and accretion . . . along the drain and

further downstream in Auvase Creek.” Id., at 98a. And it 

observed that increased runoff from the site would likely

cause downstream areas to “see an increase in possible 

flooding magnitude and frequency.” Id., at 99a. 

The conditional language in these assessments—“potential 

ability,” “possible flooding”—could suggest an undue degree

of speculation, and a reviewing court must identify substantial evidence supporting the Corps’ claims, see 5

U. S. C. §706(2)(E). Nevertheless, the record does show 

that factors relevant to the jurisdictional inquiry have 

already been noted and considered. As in Rapanos, 

though, the record gives little indication of the quantity 

and regularity of flow in the adjacent tributaries—a consideration that may be important in assessing the nexus.

Also, as in Rapanos, the legal standard applied to the facts 

was imprecise.

The Court of Appeals, considering the Carabell case 

after its Rapanos decision, framed the inquiry in terms of

whether hydrologic connection is required to establish a

significant nexus. The court held that it is not, and that 

much of its holding is correct. Given the role wetlands 

play in pollutant filtering, flood control, and runoff storage, it may well be the absence of hydrologic connection (in 

the sense of interchange of waters) that shows the wetlands’ significance for the aquatic system. In the adminis-
30 RAPANOS v. UNITED STATES 

KENNEDY, J., concurring in judgment 

trative decision under review, however, the Corps based 

its jurisdiction solely on the wetlands’ adjacency to the 

ditch opposite the berm on the property’s edge. As explained earlier, mere adjacency to a tributary of this sort 

is insufficient; a similar ditch could just as well be located 

many miles from any navigable-in-fact water and carry

only insubstantial flow towards it. A more specific inquiry, based on the significant nexus standard, is therefore necessary. Thus, a remand is again required to permit application of the appropriate legal standard. See, 

e.g., INS v. Orlando Ventura, 537 U. S. 12, 16 (2002) (per 

curiam) (“Generally speaking, a court of appeals should

remand a case to an agency for decision of a matter that 

statutes place primarily in agency hands”). 

* * * 

In these consolidated cases I would vacate the judgments

of the Court of Appeals and remand for consideration

whether the specific wetlands at issue possess a significant nexus with navigable waters. 
_________________ 

_________________ 

Cite as: 547 U. S. ____ (2006) 1 

STEVENS, J., dissenting 

SUPREME COURT OF THE UNITED STATES 

Nos. 04–1034 and 04–1384 

JOHN A. RAPANOS, ET UX., ET AL., PETITIONERS 

04–1034 v. 

UNITED STATES 

JUNE CARABELL ET AL., PETITIONERS 

04–1384 v. 

UNITED STATES ARMY CORPS OF ENGINEERS ET AL. 

ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF 

APPEALS FOR THE SIXTH CIRCUIT 

[June 19, 2006] 

JUSTICE STEVENS, with whom JUSTICE SOUTER, JUSTICE 

GINSBURG, and JUSTICE BREYER join, dissenting. 

In 1972, Congress decided to “restore and maintain the 

chemical, physical, and biological integrity of the Nation’s 

waters” by passing what we now call the Clean Water Act.

86 Stat. 816, as amended, 33 U. S. C. §1251 et seq. The 

costs of achieving the Herculean goal of ending water 

pollution by 1985, see §1251(a), persuaded President 

Nixon to veto its enactment, but both Houses of Congress

voted to override that veto by overwhelming margins. To 

achieve its goal, Congress prohibited “the discharge of any 

pollutant”—defined to include “any addition of any pollutant to navigable waters from any point source”—without a

permit issued by the Army Corps of Engineers (Army 

Corps or Corps) or the Environmental Protection Agency 

(EPA). §§1311(a), 1362(12)(A). Congress further defined

“navigable waters” to mean “the waters of the United 

States.” §1362(7).

The narrow question presented in No. 04–1034 is 
2 RAPANOS v. UNITED STATES 

STEVENS, J., dissenting 

whether wetlands adjacent to tributaries of traditionally 

navigable waters are “waters of the United States” subject

to the jurisdiction of the Army Corps; the question in No. 

04–1384 is whether a manmade berm separating a wetland from the adjacent tributary makes a difference. The 

broader question is whether regulations that have protected the quality of our waters for decades, that were

implicitly approved by Congress, and that have been 

repeatedly enforced in case after case, must now be revised in light of the creative criticisms voiced by the plurality and JUSTICE KENNEDY today. Rejecting more than

30 years of practice by the Army Corps, the plurality 

disregards the nature of the congressional delegation to

the agency and the technical and complex character of the 

issues at stake. JUSTICE KENNEDY similarly fails to defer

sufficiently to the Corps, though his approach is far more

faithful to our precedents and to principles of statutory 

interpretation than is the plurality’s. 

In my view, the proper analysis is straightforward. The 

Army Corps has determined that wetlands adjacent to

tributaries of traditionally navigable waters preserve the

quality of our Nation’s waters by, among other things, 

providing habitat for aquatic animals, keeping excessive 

sediment and toxic pollutants out of adjacent waters, and

reducing downstream flooding by absorbing water at times

of high flow. The Corps’ resulting decision to treat these 

wetlands as encompassed within the term “waters of the 

United States” is a quintessential example of the Executive’s reasonable interpretation of a statutory provision. 

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

Council, Inc., 467 U. S. 837, 842–845 (1984). 

Our unanimous decision in United States v. Riverside 

Bayview Homes, Inc., 474 U. S. 121 (1985), was faithful to

our duty to respect the work product of the Legislative and

Executive Branches of our Government. Today’s judicial 

amendment of the Clean Water Act is not. 
Cite as: 547 U. S. ____ (2006) 3 

STEVENS, J., dissenting 

I 

At each of the three sites at issue in No. 04–1034, the 

petitioners filled large areas of wetlands without permits, 

despite being on full notice of the Corps’ regulatory requirements. Because the plurality gives short shrift to the 

facts of this case—as well as to those of No. 04–1384—I 

shall discuss them at some length.

The facts related to the 230-acre Salzburg site are illustrative. In 1988, John Rapanos asked the Michigan Department of Natural Resources (MDNR) to inspect the site 

“in order to discuss with him the feasibility of building a

shopping center there.” App. to Pet. for Cert. in No. 04– 

1034, p. B15. An MDNR inspector informed Rapanos that

the land probably included wetlands that were “waters of 

the United States” and sent him an application for a permit under §404 of the Act.1 Rapanos then hired a wetland

consultant, Dr. Frederick Goff. After Dr. Goff concluded 

that the land did in fact contain many acres of wetlands, 

“Rapanos threatened to ‘destroy’ Dr. Goff if he did not 

destroy the wetland report, and refused to pay Dr. Goff

unless and until he complied.” Ibid. In the meantime, 

without applying for a permit, Rapanos hired construction

companies to do $350,000 worth of work clearing the land, 

filling in low spots, and draining subsurface water. After 

Rapanos prevented MDNR inspectors from visiting the 

site, ignored an MDNR cease-and-desist letter, and refused to obey an administrative compliance order issued 

by the EPA, the matter was referred to the Department of

Justice. In the civil case now before us, the District Court 

found that Rapanos unlawfully filled 22 acres of wetlands. 

Rapanos and his wife engaged in similar behavior at the 

Hines Road and Pine River sites. Without applying for 

§404 permits, they hired construction companies to per-

—————— 

1Pursuant to 33 U. S. C. §§1344(g)–(h), Michigan operates its own

§404 permitting program, subject to supervision from the Army Corps. 
4 RAPANOS v. UNITED STATES 

STEVENS, J., dissenting 

form extensive clearing and filling activities. They continued these activities even after receiving EPA administrative compliance orders directing them to cease the work 

immediately. They ultimately spent $158,000 at the 275-

acre Hines Road site, filling 17 of its existing 64 acres of 

wetlands. At the 200-acre Pine River site, they spent

$463,000 and filled 15 of its 49 acres of wetlands. 

Prior to their destruction, the wetlands at all three sites 

had surface connections to tributaries of traditionally 

navigable waters. The Salzburg wetlands connected to a 

drain that flows into a creek that flows into the navigable 

Kawkawlin River. The Hines Road wetlands connected to 

a drain that flows into the navigable Tittabawassee River.

And the Pine River wetlands connected with the Pine 

River, which flows into Lake Huron. 

At trial, the Government put on a wetland expert, Dr.

Daniel Willard, whom the trial court found “eminently 

qualified” and “highly credible.” Id., at B7. Dr. Willard 

testified that the wetlands at these three sites provided 

ecological functions in terms of “habitat, sediment trapping, nutrient recycling, and flood peak diminution.” 4 Tr. 

96 (Apr. 5, 1999).2 He explained: 

“[G]enerally for all of the . . . sites we have a situation 

in which the flood water attenuation in that water is 

held on the site in the wetland . . . such that it does 

not add to flood peak. By the same token it would

have some additional water flowing into the rivers 

during the drier periods, thus, increasing low water

flow. 

. . . . . 

“By the same token on all of the sites to the extent 

—————— 

2Dr. Willard did not “stud[y] the upstream drainage of these sites . . .

well enough to make a statement” about whether they also performed 

pollutant-trapping functions. 4 Tr. 96. 
Cite as: 547 U. S. ____ (2006) 5 

STEVENS, J., dissenting 

that they slow the flow of water of the site they will 

also accumulate sediment and thus trap sediment and 

hold nutrients for use in those wetland systems later 

in the season as well.” Id., at 95–96. 

The District Court found that the wetlands at all three 

sites were covered by the Clean Water Act and that the 

Rapanoses had violated the Act by destroying them without permits. The Sixth Circuit unanimously affirmed. 

376 F. 3d 629 (2004).

The facts of No. 04–1384 are less dramatic. The petitioners in that case own a 20-acre tract of land, of which 

16 acres are wetlands, located in Macomb County a mile

from Lake St. Clair. These wetlands border a ditch that 

flows into a drain that flows into a creek that flows into 

Lake St. Clair. A 4-foot-wide manmade berm separates 

the wetlands from the ditch; thus water rarely if ever

passes from wetlands to ditch or vice versa. 

Petitioners applied for a permit to fill most of these

wetlands with 57,500 cubic yards of material. They intended to build a 112-unit condominium development on 

the site. After inspecting the site and considering comments from, among others, the Water Quality Unit of the 

Macomb County Prosecutor’s Office (which urged the

Corps to deny the permit because “[t]he loss of this high

quality wetland area would have an unacceptable adverse

effect on wildlife, water quality, and conservation of wetlands resources,” App. in No. 04–1384, p. 79a), the Corps

denied the permit. Id., at 84a–126a. As summarized in a 

letter sent to petitioners, reasons for denial included: 

“Your parcel is primarily a forested wetland that provides valuable seasonal habitat for aquatic organisms

and year round habitat for terrestrial organisms. Additionally, the site provides water storage functions 

that, if destroyed, could result in an increased risk of

erosion and degradation of water quality in the Suth-
6 RAPANOS v. UNITED STATES 

STEVENS, J., dissenting 

erland-Oemig Drain, Auvase Creek, and Lake St. 

Clair. The minimization of impacts to these wetlands 

is important for conservation and the overall ecology 

of the region. Because the project development area is 

a forested wetland, the proposed project would destroy 

the resources in such a manner that they would not 

soon recover from impacts of the discharges. The extent of impacts in the project area when considered

both individually and cumulatively would be unacceptable and contrary to the public interest.” Id., at 

127a–128a. 

As in No. 04–1034, the unanimous judgment of the District and Circuit Judges was that the Corps has jurisdiction over this wetland because it is adjacent to a tributary 

of traditionally navigable waters. 391 F. 3d 704 (CA6 

2004). The Solicitor General defends both judgments. 

II 

Our unanimous opinion in Riverside Bayview squarely

controls these cases. There, we evaluated the validity of 

the very same regulations at issue today. These regulations interpret “waters of the United States” to cover all 

traditionally navigable waters; tributaries of these waters;

and wetlands adjacent to traditionally navigable waters or 

their tributaries. 33 CFR §§328.3(a)(1), (5), and (7) (2005); 

§§323.2(a)(1), (5), and (7) (1985). Although the particular 

wetland at issue in Riverside Bayview abutted a navigable

creek, we framed the question presented as whether the 

Clean Water Act “authorizes the Corps to require landowners to obtain permits from the Corps before discharging fill material into wetlands adjacent to navigable bodies

of water and their tributaries.” 474 U. S., at 123 (emphasis added).3 

—————— 

3By contrast, we “d[id] not express any opinion” on the Corps’ additional assertion of jurisdiction over “wetlands that are not adjacent to 
Cite as: 547 U. S. ____ (2006) 7 

STEVENS, J., dissenting 

We held that, pursuant to our decision in Chevron, 

“our review is limited to the question whether it is

reasonable, in light of the language, policies, and legislative history of the Act for the Corps to exercise jurisdiction over wetlands adjacent to but not regularly

flooded by rivers, streams, and other hydrographic

features more conventionally identifiable as ‘waters.’” 

474 U. S., at 131. 

Applying this standard, we held that the Corps’ decision 

to interpret “waters of the United States” as encompassing 

such wetlands was permissible. We recognized the practical difficulties in drawing clean lines between land and 

water, id., at 132, and deferred to the Corps’ judgment 

that treating adjacent wetlands as “waters” would advance 

the “congressional concern for protection of water quality 

and aquatic ecosystems,” id., at 133. 

—————— 

bodies of open water, see 33 CFR §323.2(a)(2) and (3) (1985).” 474 U. S., 

at 131–132, n. 8; see also id., at 124, n. 2 (making the same reservation). Contrary to JUSTICE KENNEDY’s reading, ante, at 23–24 (opinion

concurring in judgment), we were not reserving the issue of the Corps’ 

jurisdiction over wetlands adjacent to tributaries, but only reserving 

the issue of the Corps’ jurisdiction over truly isolated waters. A glance 

at the cited regulation makes this clear. Section 323.2(a)(2) refers to

“[a]ll interstate waters including interstate wetlands” and §323.2(a)(3) 

covers “[a]ll other waters such as intrastate lakes, rivers, streams 

(including intermittent streams), mudflats, sandflats, wetlands, 

sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds, 

the use, degradation or destruction of which could affect interstate or

foreign commerce including any such waters.” See also Solid Waste 

Agency of Northern Cook Cty. v. Army Corps of Engineers, 531 U. S. 159, 

163–164 (2001) (considering the validity of an application of §328.3(a)(3)

(1999), which is substantively identical to §323.2(a)(3) (1985) and to

§323.2(a)(5) (1978)). Wetlands adjacent to tributaries of traditionally

navigable waters were covered in the 1985 regulation by other provisions of the regulation, namely a combination of §§323.2(a)(1) (covering

traditionally navigable waters), (4) (covering tributaries of subsection

(a)(1) waters), and (7) (covering wetlands adjacent to subsection (a)(4)

waters). 
8 RAPANOS v. UNITED STATES 

STEVENS, J., dissenting 

Contrary to the plurality’s revisionist reading today, 

ante, at 21–24, 28–29, Riverside Bayview nowhere implied 

that our approval of “adjacent” wetlands was contingent

upon an understanding that “adjacent” means having a

“continuous surface connection” between the wetland and 

its neighboring creek, ante, at 23. Instead, we acknowledged that the Corps defined “adjacent” as including 

wetlands “‘that form the border of or are in reasonable 

proximity to other waters’” and found that the Corps 

reasonably concluded that adjacent wetlands are part of 

the waters of the United States. 474 U. S., at 134 (quoting 

42 Fed. Reg. 37128 (1977)). Indeed, we explicitly acknowledged that the Corps’ jurisdictional determination was 

reasonable even though 

“not every adjacent wetland is of great importance to

the environment of adjoining bodies of water. . . . If it

is reasonable for the Corps to conclude that in the majority of cases, adjacent wetlands have significant effects on water quality and the ecosystem, its definition can stand. That the definition may include some

wetlands that are not significantly intertwined with 

the ecosystem of adjacent waterways is of little moment, for where it appears that a wetland covered by 

the Corps’ definition is in fact lacking in importance to

the aquatic environment . . . the Corps may always allow development of the wetland for other uses simply

by issuing a permit.” 474 U. S., at 135, n. 9. 

In closing, we emphasized that the scope of the Corps’

asserted jurisdiction over wetlands had been specifically 

brought to Congress’ attention in 1977, that Congress had 

rejected an amendment that would have narrowed that

jurisdiction, and that even proponents of the amendment 

would not have removed wetlands altogether from the 

definition of “waters of the United States.” Id., at 135– 

139. 
Cite as: 547 U. S. ____ (2006) 9 

STEVENS, J., dissenting 

Disregarding the importance of Riverside Bayview, the 

plurality relies heavily on the Court’s subsequent opinion 

in Solid Waste Agency of Northern Cook Cty. v. Army 

Corps of Engineers, 531 U. S. 159 (2001) (SWANCC). In 

stark contrast to Riverside Bayview, however, SWANCC 

had nothing to say about wetlands, let alone about wetlands adjacent to traditionally navigable waters or their 

tributaries. Instead, SWANCC dealt with a question

specifically reserved by Riverside Bayview, see n. 3, supra, 

namely, the Corps’ jurisdiction over isolated waters—

“‘waters that are not part of a tributary system to interstate waters or to navigable waters of the United States, 

the degradation or destruction of which could affect interstate commerce.’” 531 U. S., at 168–169 (quoting 33 CFR 

§323.2(a)(5) (1978); emphasis added); see also 531 U. S., at 

163 (citing 33 CFR §328.2(a)(3) (1999), which is the later

regulatory equivalent to §323.2(a)(5) (1978)). At issue in 

SWANCC was “an abandoned sand and gravel pit . . . 

which provide[d] habitat for migratory birds” and contained a few pools of “nonnavigable, isolated, intrastate 

waters.” 531 U. S., at 162, 166. The Corps had asserted

jurisdiction over the gravel pit under its 1986 Migratory

Bird Rule, which treated isolated waters as within its 

jurisdiction if migratory birds depended upon these waters. The Court rejected this jurisdictional basis since

these isolated pools, unlike the wetlands at issue in Riverside Bayview, had no “significant nexus” to traditionally 

navigable waters. 531 U. S., at 167. In the process, the 

Court distinguished Riverside Bayview’s reliance on Congress’ decision to leave the Corps’ regulations alone when 

it amended the Act in 1977, since “‘[i]n both Chambers,

debate on the proposals to narrow the definition of navigable waters centered largely on the issue of wetlands

preservation’” rather than on the Corps’ jurisdiction over 
10 RAPANOS v. UNITED STATES 

STEVENS, J., dissenting 

truly isolated waters. 531 U. S., at 170 (quoting 474 U. S., 

at 136).4

 Unlike SWANCC and like Riverside Bayview, the cases 

before us today concern wetlands that are adjacent to 

“navigable bodies of water [or] their tributaries,” 474 

U. S., at 123. Specifically, these wetlands abut tributaries

of traditionally navigable waters. As we recognized in 

Riverside Bayview, the Corps has concluded that such

wetlands play important roles in maintaining the quality 

of their adjacent waters, see id., at 134–135, and consequently in the waters downstream. Among other things,

wetlands can offer “nesting, spawning, rearing and resting 

sites for aquatic or land species”; “serve as valuable stor-

—————— 

4As THE CHIEF JUSTICE observes, the Corps and the EPA initially

considered revising their regulations in response to SWANCC. Ante, at 

1–2 (concurring opinion). THE CHIEF JUSTICE neglects to mention,

however, that almost all of the 43 States to submit comments opposed 

any significant narrowing of the Corps’ jurisdiction—as did roughly 

99% of the 133,000 other comment submitters. See U. S. General 

Accounting Office, Report to the Chairman, Subcommittee on Energy 

Policy, Natural Resources and Regulating Affairs, Committee on 

Government Reform, House of Representatives, Waters and Wetlands:

Corps of Engineers Needs to Evaluate Its District Office Practices in 

Determining Jurisdiction, GAO–04–297, pp. 14–15 (Feb. 2004), 

http://www.gao.gov/new.items/d04297.pdf (hereinafter GAO Report) (all 

Internet materials as visited June 14, 2006, and available in Clerk of 

Court’s case file); Brief for Association of State and Interstate Water

Pollution Control Administrators as Amicus Curiae. In any event, the

agencies’ decision to abandon their rulemaking is hardly responsible for

the cases at hand. The proposed rulemaking focused on isolated 

waters, which are covered by 33 CFR §328.3(a)(3) (1999) and which

were called into question by SWANCC, rather than on wetlands adjacent to tributaries of navigable waters, which are covered by a combination of §§328.3(a)(1), (5), and (7) and which (until now) seemed obviously within the agencies’ jurisdiction in light of Riverside Bayview. 

See 68 Fed. Reg. 1994 (2003) (“The agencies seek comment on the use 

of the factors in 33 CFR 328.3(a)(3)(i)–(iii) . . . in determining

[Clean Water Act] jurisdiction over isolated, intrastate, non-navigable 

waters”). 
Cite as: 547 U. S. ____ (2006) 11 

STEVENS, J., dissenting 

age areas for storm and flood waters”; and provide “significant water purification functions.” 33 CFR §320.4(b)(2) 

(2005); 474 U. S., at 134–135. These values are hardly 

“independent” ecological considerations as the plurality

would have it, ante, at 23—instead, they are integral to

the “chemical, physical, and biological integrity of the

Nation’s waters,” 33 U. S. C. §1251(a). Given that wetlands serve these important water quality roles and given

the ambiguity inherent in the phrase “waters of the 

United States,” the Corps has reasonably interpreted its

jurisdiction to cover non-isolated wetlands. See 474 U. S., 

at 131–135.5 

This conclusion is further confirmed by Congress’ deliberate acquiescence in the Corps’ regulations in 1977. Id., 

at 136. Both Chambers conducted extensive debates 

about the Corps’ regulatory jurisdiction over wetlands,

rejected efforts to limit this jurisdiction, and appropriated 

—————— 

5Unsurprisingly, most Courts of Appeals to consider the scope of the 

Corps’ jurisdiction after SWANCC have unhesitatingly concluded that 

this jurisdiction covers intermittent tributaries and wetlands adjacent—in the normal sense of the word—to traditionally navigable 

waters and their tributaries. E.g., United States v. Deaton, 332 F. 3d 

698 (CA4 2003) (upholding the Corps’ jurisdiction over wetlands adjacent to a ditch that might not contain consistently flowing water but

did drain into another ditch that drained into a creek that drained into 

a navigable waterway); Headwaters, Inc. v. Talent Irrigation Dist., 243 

F. 3d 526 (CA9 2001) (treating as “waters of the United States” canals

that held water intermittently and connected to other tributaries of 

navigable waters); United States v. Rueth Development Co., 335 F. 3d 

598, 604 (CA7 2003) (observing “it is clear that SWANCC did not affect 

the law regarding . . . adjacency” in upholding the Corps’ jurisdiction 

over a wetland without finding that this wetland had a continuous

surface connection to its adjacent tributary); Baccarat Fremont v. U. S. 

Army Corps of Engineers, 425 F. 3d 1150, 1156 (CA9 2005) (upholding

the Corps’ jurisdiction over wetlands separated by berms from traditionally navigable channels and observing that “SWANCC simply did

not address the issue of jurisdiction over adjacent wetlands”); but see 

In re Needham, 354 F. 3d 340 (CA5 2003) (reading “waters of the 

United States” narrowly as used in the Oil Pollution Act of 1990). 
12 RAPANOS v. UNITED STATES 

STEVENS, J., dissenting 

funds for a “‘National Wetlands Inventory’” to help the 

States “‘in the development and operation of programs 

under this Act.’” Id., at 135–139 (quoting 33 U. S. C. 

§1288(i)(2)). We found these facts significant in Riverside 

Bayview, see 474 U. S., at 135–139, as we acknowledged in 

SWANCC. See 531 U. S., at 170–171 (noting that

“[b]eyond Congress’ desire to regulate wetlands adjacent to 

‘navigable waters,’ respondents point us to no persuasive 

evidence” of congressional acquiescence (emphasis added)). 

The Corps’ exercise of jurisdiction is reasonable even

though not every wetland adjacent to a traditionally navigable water or its tributary will perform all (or perhaps

any) of the water quality functions generally associated 

with wetlands. Riverside Bayview made clear that jurisdiction does not depend on a wetland-by-wetland inquiry. 

474 U. S., at 135, n. 9. Instead, it is enough that wetlands

adjacent to tributaries generally have a significant nexus 

to the watershed’s water quality. If a particular wetland

is “not significantly intertwined with the ecosystem of

adjacent waterways,” then the Corps may allow its development “simply by issuing a permit.” Ibid.6 Accordingly,

for purposes of the Corps’ jurisdiction it is of no significance that the wetlands in No. 04–1034 serve flood control 

and sediment sink functions, but may not do much to trap 

other pollutants, supra, at 4–5, and n. 2, or that the wetland in No. 04–1328 keeps excess water from Lake St. 

Clair but may not trap sediment, see supra, at 5–6. 

Seemingly alarmed by the costs involved, the plurality

shies away from Riverside Bayview’s recognition that

jurisdiction is not a case-by-case affair. I do not agree 

with the plurality’s assumption that the costs of preserving wetlands are unduly high. It is true that the cost of 

—————— 

6 Indeed, “[t]he Corps approves virtually all section 404 permit[s],” 

though often requiring applicants to avoid or mitigate impacts to 

wetlands and other waters. GAO Report 8. 
Cite as: 547 U. S. ____ (2006) 13 

STEVENS, J., dissenting 

§404 permits are high for those who must obtain them7— 

but these costs amount to only a small fraction of 1% of 

the $760 billion spent each year on private and public 

construction and development activity. Sunding & Zilberman 80. More significant than the plurality’s exaggerated concern about costs, however, is the fact that its 

omission of any discussion of the benefits that the regulations at issue have produced sheds a revelatory light on

the quality (and indeed the impartiality) of its cost-benefit 

analysis.8 The importance of wetlands for water quality

is hard to overstate. See, e.g., U. S. Congress, Office 

—————— 

7According to the Sunding and Zilberman article cited by the plurality, ante, at 2, for 80% of permits the mean cost is about $29,000 (with a 

median cost of about $12,000). The Economics of Environmental 

Regulation by Licensing: An Assessment of Recent Changes to the 

Wetland Permitting Process, 42 Natural Resources J. 59, 63, 74 (2002)

(hereinafter Sunding & Zilberman). Only for less than 20% of the 

permits—those for projects with the most significant impacts on wetlands—is the mean cost around $272,000 (and the median cost is 

$155,000). Ibid. 

Of course, not every placement of fill or dredged material into the

waters of the United States requires a §404 permit. Only when such

fill comes from point sources—“discernible, confined and discrete 

conveyance[s]”—is a §404 permit needed. 33 U. S. C. §§1362(12), (14).

Moreover, permits are not required for discharges from point sources 

engaged in, among other things, normal farming activities; maintenance of transportation structures; and construction of irrigation 

ditches, farm roads, forest roads, and temporary mining roads. 

§1344(f). 8Rather than defending its own antagonism to environmentalism, the

plurality counters by claiming that my dissent is “policy-laden.” Ante, 

at 28. The policy considerations that have influenced my thinking are 

Congress’ rather than my own. In considering whether the Corps’ 

interpretation of its jurisdiction is reasonable, I am admittedly taking

into account the congressional purpose of protecting the physical, 

chemical, and biological integrity of our waters. See 33 U. S. C. 

§1251(a); see also Chevron U. S. A. Inc. v. Natural Resources Defense 

Council, Inc., 467 U. S. 863, 837 (1984) (considering whether the agency

regulation was consistent with “the policy concerns that motivated the

[Clean Air Act’s] enactment”). 
14 RAPANOS v. UNITED STATES 

STEVENS, J., dissenting 

of Technology Assessment, Wetlands: Their Use and 

Regulation, OTA–206, pp. 43–61 (Mar. 1984), 

http://govinfo.library.unt.edu/ota/Ota_4/DATA/1984/8433.PDF 

(hereinafter OTA) (describing wetlands’ role in floodpeak 

reduction, shoreline protection, ground water recharge, 

trapping of suspended sediment, filtering of toxic pollutants, and protection of fish and wildlife). See also ante, at 

20 (KENNEDY, J., concurring in judgment). Unsurprisingly, the Corps’ approach has the overwhelming endorsement of numerous amici curiae, including 33 States

and the county in which the property in No. 04–1384 is

located. 

In final analysis, however, concerns about the appropriateness of the Corps’ 30-year implementation of the Clean 

Water Act should be addressed to Congress or the Corps 

rather than to the Judiciary. Whether the benefits of 

particular conservation measures outweigh their costs is a

classic question of public policy that should not be answered by appointed judges. The fact that large investments are required to finance large developments merely

means that those who are most adversely affected by the 

Corps’ permitting decisions are persons who have the 

ability to communicate effectively with their representatives. Unless and until they succeed in convincing Congress (or the Corps) that clean water is less important

today than it was in the 1970’s, we continue to owe deference to regulations satisfying the “evident breadth of

congressional concern for protection of water quality and 

aquatic ecosystems” that all of the Justices on the Court in

1985 recognized in Riverside Bayview, 474 U. S., at 133. 

III 

Even setting aside the plurality’s dramatic departure

from our reasoning and holding in Riverside Bayview, its 

creative opinion is utterly unpersuasive. The plurality

imposes two novel conditions on the exercise of the Corps’ 
Cite as: 547 U. S. ____ (2006) 15 

STEVENS, J., dissenting 

jurisdiction that can only muddy the jurisdictional waters.

As JUSTICE KENNEDY observes, “these limitations . . . are 

without support in the language and purposes of the Act

or in our cases interpreting it.” Ante, at 11 (opinion concurring in judgment). The impropriety of crafting these 

new conditions is highlighted by the fact that no party or 

amicus has suggested either of them.9 

First, ignoring the importance of preserving jurisdiction

over water beds that are periodically dry, the plurality 

imposes a requirement that only tributaries with the 

“relatively permanent” presence of water fall within the

Corps’ jurisdiction. Ante, at 13–14. Under the plurality’s

view, then, the Corps can regulate polluters who dump

dredge into a stream that flows year round but may not be

able to regulate polluters who dump into a neighboring

stream that flows for only 290 days of the year—even if

the dredge in this second stream would have the same 

effect on downstream waters as the dredge in the yearround one. Ante, at 14, n. 5.10 

To find this arbitrary distinction compelled by the statute, the plurality cites a dictionary for a proposition that it

does not contain. The dictionary treats “streams” as “wa-

—————— 

9Only 3 of the 21 amici briefs filed on petitioners’ behalf come even 

close to asking for one of the plurality’s two conditions. These briefs 

half-argue that intermittent streams should fall outside the Corps’ 

jurisdiction—though not for the reasons given by the plurality. See 

Brief for National Stone, Sand and Gravel Assn. et al. 20, n. 7; Brief for 

Foundation for Environmental and Economic Progress et al. 22–23; 

Brief for Western Coalition of Arid States 10. 10The plurality does suggest that “seasonal rivers” are not “necessarily exclude[d]” from the Corps’ jurisdiction—and then further suggests

that “streams” are “rivers.” Ante, at 14, n. 5. I will not explore the 

semantic issues posed by the latter point. On the former point, I have

difficulty understanding how a “seasonal” river could meet the plurality’s test of having water present “relatively permanent[ly].” By failing

to explain itself, the plurality leaves litigants without guidance as to 

where the line it draws between “relatively permanent” and “intermittent” lies. 
16 RAPANOS v. UNITED STATES 

STEVENS, J., dissenting 

ters” but has nothing to say about whether streams must 

contain water year round to qualify as “streams.” Ante, at 

13–14, and n. 6 (citing Webster’s New International Dictionary 2493 (2d ed. 1954) (hereinafter Webster’s Second), 

as defining stream as a “‘current or course of water or

other fluid, flowing on the earth’”). From this, the plurality somehow deduces that streams can never be intermittent or ephemeral (i.e., flowing for only part of the 

year). Ante, at 13–15, and nn. 5–6. But common 

sense and common usage demonstrate that intermittent streams, like perennial streams, are still 

streams.11 See, e.g., U. S. Dept. of Interior, U. S. Geological Survey, Topographic Map Symbols 3 (2005), 

http://erg.usgs.gov/isb/pubs/booklets/symbols/ (identifying

symbols for “[p]erennial stream” and “[i]ntermittent 

stream,” as well as for “[p]erennial river” and 

“[i]ntermittent river”). This was true well before the 

passage of the Act in 1972. E.g., Webster’s Third New 

International Dictionary 1180 (1961) (hereinafter Webster’s Third) (linking “intermittent” with “stream”). Indeed, we ourselves have used the term “intermittent 

stream” as far back as 1932. Harrisonville v. W. S. Dickey 

Clay Mfg. Co., 289 U. S. 334, 335 (1933). Needless to say,

Justice Brandeis’ use of the term in a unanimous opinion 

should not be dismissed as merely a “useful oxymor[on],” 

ante, at 15, n. 6 (plurality opinion). 

The plurality attempts to bolster its arbitrary jurisdictional line by citing two tangential statutory provisions 

—————— 

11 Indeed, in the 1977 debate over whether to restrict the scope of the 

Corps’ regulatory power, Senator Bentsen recognized that the Corps’ 

jurisdiction “cover[s] all waters of the United States, including small 

streams, ponds, isolated marshes, and intermittently flowing gullies.”

4 Legislative History of the Clean Water Act of 1977 (Committee Print

compiled for the Senate Committee on Environment and Public Works 

by the Library of Congress), Ser. No. 95–14, p. 903 (1978). His proposed amendment to restrict this jurisdiction failed. Id., at 947. 
Cite as: 547 U. S. ____ (2006) 17 

STEVENS, J., dissenting 

and two inapplicable canons of construction. None comes 

close to showing that Congress directly spoke to whether 

“waters” requires the relatively permanent presence of 

water. 

The first provision relied on by the plurality—the definition of “point source” in 33 U. S. C. §1362(14)—has no 

conceivable bearing on whether permanent tributaries 

should be treated differently from intermittent ones, since

“pipe[s], ditch[es], channel[s], tunnel[s], conduit[s], [and] 

well[s]” can all hold water permanently as well as intermittently.12 The second provision is §1251(b), which announces a congressional policy to “recognize, preserve, and 

protect the primary responsibilities and rights of States” 

to prevent pollution, to plan development, and to consult 

with the EPA. Under statutory additions made in 1977 

when Congress considered and declined to alter the Corps’ 

—————— 

12The plurality’s reasoning to the contrary is mystifying. The plurality emphasizes that a ditch around a castle is also called a “moat” and 

that a navigable manmade channel is called a “canal.” See ante, at 17, 

n. 7. On their face (and even after much head-scratching), these points

have nothing to do with whether we use the word “stream” rather than

“ditch” where permanently present water is concerned. Indeed, under

the plurality’s reasoning, we would call a “canal” a “stream” or a “river” 

rather than a “canal.” 

Moreover, we do use words like “ditch” without regard to whether 

water is present relatively permanently. In Jennison v. Kirk, 98 U. S. 

453 (1879), for example, Justice Field used the term “ditch”—not 

“stream”—in describing a manmade structure that carried water year

round. See also, e.g., Knoxville Water Co. v. Knoxville, 200 U. S. 22, 27 

(1906) (opinion for the Court by Harlan, J.) (describing “pipes” that

would continuously carry water); ante, at 20, 24 (plurality opinion)

(using “channel” with reference to both intermittent and relatively 

permanent waters); PUD No. 1 of Jefferson Cty. v. Washington Dept. of 

Ecology, 511 U. S. 700, 709 (1994) (describing a “tunnel” that would

carry water year round); New Orleans Water-Works Co. v. Rivers, 115 

U. S. 674, 683 (1885) (opinion for the Court by Harlan, J.) (describing

“conduits” that would supply water for a hotel). The plurality’s attempt

to achieve its desired outcome by redefining terms does no credit to

lexicography—let alone to justice. 
18 RAPANOS v. UNITED STATES 

STEVENS, J., dissenting 

interpretation of its broad regulatory jurisdiction, the 

States may run their own §404 programs. §§1344(g)–(h). 

As modified, §1251(b) specifically recognizes this role for

the States as part of their primary responsibility for preventing water pollution. Even focusing only on the Act as

it stood between 1972 and 1977, but see International 

Paper Co. v. Ouellette, 479 U. S. 481, 489–490 (1987) (interpreting §1251(b) in light of the 1977 additions), broad exercise of jurisdiction by the Corps still left the States with

ample rights and responsibilities. See S. D. Warren Co. v. 

Maine Bd. of Environmental Protection, 547 U. S. __, __ 

(2006) (slip op., at 14–15). States had the power to impose

tougher water pollution standards than required by the 

Act, §1370, and to prevent the Corps and the EPA from

issuing permits, §1341(a)(1)—not to mention nearly exclusive responsibility for containing pollution from nonpoint 

sources. 

The two canons of construction relied on by the plurality

similarly fail to overcome the deference owed to the Corps. 

First, the plurality claims that concerns about intruding

on state power to regulate land use compel the conclusion 

that the phrase “waters of the United States” does not

cover intermittent streams. As we have recognized, however, Congress found it “‘essential that discharge of pollutants be controlled at the source,’” Riverside Bayview,

474 U. S., at 133 (quoting S. Rep. No. 92–414, p. 77

(1972)), and the Corps can define “waters” broadly to 

accomplish this aim. Second, the plurality suggests that

the canon of constitutional avoidance applies because the

Corps’ approach might exceed the limits of our Commerce

Clause authority. Setting aside whether such a concern 

was proper in SWANCC, 531 U. S., at 173; but see id., at 

192–196 (STEVENS, J., dissenting), it is plainly not warranted here. The wetlands in these cases are not “isolated” but instead are adjacent to tributaries of traditionally navigable waters and play important roles in the 
Cite as: 547 U. S. ____ (2006) 19 

STEVENS, J., dissenting 

watershed, such as keeping water out of the tributaries or

absorbing water from the tributaries. “There is no constitutional reason why Congress cannot, under the commerce 

power, treat the watersheds as a key to flood control on 

navigable streams and their tributaries.” Oklahoma ex rel. 

Phillips v. Guy F. Atkinson Co., 313 U. S. 508, 525 (1941).

Most importantly, the plurality disregards the fundamental significance of the Clean Water Act. As thenJustice Rehnquist explained when writing for the Court in

1981, the Act was “not merely another law” but rather was

“viewed by Congress as a ‘total restructuring’ and ‘complete rewriting’ of the existing water pollution legislation.” 

Milwaukee v. Illinois, 451 U. S. 304, 317. “Congress’ intent 

in enacting the [Act] was clearly to establish an allencompassing program of water pollution regulation,” and

“the most casual perusal of the legislative history demonstrates that . . . views on the comprehensive nature of the

legislation were practically universal.” Id., at 318, and 

n. 12; see also 531 U. S., at 177–181 (STEVENS, J., dissenting). The Corps has concluded that it must regulate pollutants at the time they enter ditches or streams with

ordinary high-water marks—whether perennial, intermittent, or ephemeral—in order to properly control water

pollution. 65 Fed. Reg. 12823 (2000). Because there is 

ambiguity in the phrase “waters of the United States” and

because interpreting it broadly to cover such ditches and 

streams advances the purpose of the Act, the Corps’ approach should command our deference. Intermittent 

streams can carry pollutants just as perennial streams

can, and their regulation may prove as important for flood

control purposes. The inclusion of all identifiable tributaries that ultimately drain into large bodies of water within 

the mantle of federal protection is surely wise.

The plurality’s second statutory invention is as arbitrary as its first. Trivializing the significance of changing 

conditions in wetlands environments, the plurality im-
20 RAPANOS v. UNITED STATES 

STEVENS, J., dissenting 

poses a separate requirement that “the wetland has a

continuous surface connection” with its abutting waterway

such that it is “difficult to determine where the ‘water’ 

ends and the ‘wetland’ begins.” Ante, at 24. An “intermittent, physically remote hydrologic connection” between the

wetland and other waters is not enough. Ibid. Under this 

view, wetlands that border traditionally navigable waters

or their tributaries and perform the essential function of 

soaking up overflow waters during hurricane season—

thus reducing flooding downstream—can be filled in by

developers with impunity, as long as the wetlands lack a

surface connection with the adjacent waterway the rest of 

the year.

The plurality begins reasonably enough by recognizing

that the Corps may appropriately regulate all wetlands 

“‘adjacent to’” other waters. Ante, at 21. This recognition 

is wise, since the statutory text clearly accepts this standard. Title 33 U. S. C. §1344(g)(1), added in 1977, includes “adjacent wetlands” in its description of “waters”

and thus “expressly stated that the term ‘waters’ included

adjacent wetlands.” Riverside Bayview, 474 U. S., at 138. 

While this may not “conclusively determine the construction to be placed on the use of the term ‘waters’ elsewhere

in the Act . . . , in light of the fact that the various provisions of the Act should be read in pari materia, it does at 

least suggest strongly that the term ‘waters’ as used in the 

Act does not necessarily exclude ‘wetlands.’” Id., at 138, 

n. 11. 

The plurality goes on, however, to define “‘adjacent to’” 

as meaning “with a continuous surface connection to” 

other water. Ante, at 21–24. It is unclear how the plurality reached this conclusion, though it plainly neglected to 

consult a dictionary. Even its preferred Webster’s Second

defines the term as “[l]ying near, close, or contiguous;

neighboring; bordering on” and acknowledges that 

“[o]bjects are ADJACENT when they lie close to each other, 
Cite as: 547 U. S. ____ (2006) 21 

STEVENS, J., dissenting 

but not necessarily in actual contact.” Webster’s Second 32 

(emphasis added); see also Webster’s Third 26. In any 

event, the proper question is not how the plurality would 

define “adjacent,” but whether the Corps’ definition is

reasonable. 

The Corps defines “adjacent” as “bordering, contiguous,

or neighboring,” and specifies that “[w]etlands separated

from other waters of the United States by man-made dikes 

or barriers, natural river berms, beach dunes and the like 

are ‘adjacent wetlands.’” 33 CFR §328.3(c) (2005). This 

definition is plainly reasonable, both on its face and in

terms of the purposes of the Act. While wetlands that are 

physically separated from other waters may perform less

valuable functions, this is a matter for the Corps to evaluate in its permitting decisions. We made this clear in 

Riverside Bayview, 474 U. S., at 135, n. 9—which did not 

impose the plurality’s new requirement despite an absence

of evidence that the wetland at issue had the sort of continuous surface connection required by the plurality today.

See supra, at 7; see also ante, at 15–17 (KENNEDY, J., 

concurring in judgment) (observing that the plurality’s

requirement is inconsistent with Riverside Bayview). And 

as the facts of No. 04–1384 demonstrate, wetland separated by a berm from adjacent tributaries may still prove

important to downstream water quality. Moreover, Congress was on notice of the Corps’ definition of “adjacent”

when it amended the Act in 1977 and added 33 U. S. C. 

§1344(g)(1). See 42 Fed. Reg. 37129 (1977).

Finally, implicitly recognizing that its approach endangers the quality of waters which Congress sought to protect, the plurality suggests that the EPA can regulate

pollutants before they actually enter the “waters of the

United States.” Ante, at 24–27. I express no view on the 

merits of the plurality’s reasoning, which relies heavily on 

a respect for lower court judgments that is conspicuously 

lacking earlier in its opinion, ante, at 8–10. 
22 RAPANOS v. UNITED STATES 

STEVENS, J., dissenting 

I do fail to understand, however, why the plurality 

would not similarly apply this logic to dredged and fill 

material. The EPA’s authority over pollutants (other than 

dredged and fill materials) stems from the identical statutory language that gives rise to the Corps’ §404 jurisdiction. The plurality claims that there is a practical difference, asserting that dredged and fill material “does not 

normally wash downstream.” Ante, at 26. While more of 

this material will probably stay put than is true of soluble 

pollutants, the very existence of words like “alluvium” and 

“silt” in our language, see Webster’s Third 59, 2119, suggests that at least some fill makes its way downstream. 

See also, e.g., United States v. Deaton, 332 F. 3d 698, 707 

(CA4 2003) (“Any pollutant or fill material that degrades 

water quality in a tributary has the potential to move

downstream and degrade the quality of the navigable

waters themselves”). Moreover, such fill can harm the 

biological integrity of downstream waters even if it largely 

stays put upstream. The Act’s purpose of protecting fish,

see 33 U. S. C. §1251(a)(2); S. D. Warren Co., 547 U. S., at 

__ (slip op., at 13–14), could be seriously impaired by 

sediment in upstream waters where fish spawn, since

excessive sediment can “smother bottom-dwelling invertebrates and impair fish spawning,” OTA 48. See also, e.g.,

Erman & Hawthorne, The Quantitative Importance of an 

Intermittent Stream in the Spawning of Rainbow Trout,

105 Transactions of the American Fisheries Society 675–

681 (1976); Brief for American Rivers et al. as Amici Curiae 14 (observing that anadromous salmon often spawn in 

small, intermittent streams). 

IV 

While I generally agree with Parts I and II–A of 

JUSTICE KENNEDY’s opinion, I do not share his view that 

we should replace regulatory standards that have been in

place for over 30 years with a judicially crafted rule dis-
Cite as: 547 U. S. ____ (2006) 23 

STEVENS, J., dissenting 

tilled from the term “significant nexus” as used in 

SWANCC. To the extent that our passing use of this term

has become a statutory requirement, it is categorically 

satisfied as to wetlands adjacent to navigable waters or

their tributaries. Riverside Bayview and SWANCC together make this clear. SWANCC’s only use of the term

comes in the sentence: “It was the significant nexus between the wetlands and ‘navigable waters’ that informed

our reading of the [Clean Water Act] in Riverside Bayview.” 531 U. S., at 167. Because Riverside Bayview was 

written to encompass “wetlands adjacent to navigable

waters and their tributaries,” 474 U. S., at 123, and reserved only the question of isolated waters, see id., at 131– 

132, n. 8; see also n. 3, supra, its determination of the 

Corps’ jurisdiction applies to the wetlands at issue in

these cases. 

Even setting aside the apparent applicability of Riverside Bayview. I think it clear that wetlands adjacent to 

tributaries of navigable waters generally have a “significant nexus” with the traditionally navigable waters downstream. Unlike the “nonnavigable, isolated, intrastate 

waters” in SWANCC, 531 U. S., at 171, these wetlands can 

obviously have a cumulative effect on downstream water

flow by releasing waters at times of low flow or by keeping

waters back at times of high flow. This logical connection

alone gives the wetlands the “limited” connection to traditionally navigable waters that is all the statute requires, 

see id., at 172; 474 U. S., at 133—and disproves JUSTICE 

KENNEDY’s claim that my approach gives no meaning to

the word “‘navigable,’” ante, at 21 (opinion concurring in

judgment). Similarly, these wetlands can preserve downstream water quality by trapping sediment, filtering toxic

pollutants, protecting fish-spawning grounds, and so forth. 

While there may exist categories of wetlands adjacent to

tributaries of traditionally navigable waters that, taken

cumulatively, have no plausibly discernable relationship 
24 RAPANOS v. UNITED STATES 

STEVENS, J., dissenting 

to any aspect of downstream water quality, I am skeptical.

And even given JUSTICE KENNEDY’s “significant nexus” 

test, in the absence of compelling evidence that many such

categories do exist I see no reason to conclude that the 

Corps’ longstanding regulations are overbroad. 

JUSTICE KENNEDY’s “significant nexus” test will probably not do much to diminish the number of wetlands covered by the Act in the long run. JUSTICE KENNEDY himself recognizes that the records in both cases contain 

evidence that “should permit the establishment of a significant nexus,” ante, at 27, see also ante, at 26, and it 

seems likely that evidence would support similar findings

as to most (if not all) wetlands adjacent to tributaries of 

navigable waters. But JUSTICE KENNEDY’s approach will

have the effect of creating additional work for all concerned parties. Developers wishing to fill wetlands adjacent to ephemeral or intermittent tributaries of traditionally navigable waters will have no certain way of knowing 

whether they need to get §404 permits or not. And the 

Corps will have to make case-by-case (or category-bycategory) jurisdictional determinations, which will inevitably increase the time and resources spent processing

permit applications. These problems are precisely the 

ones that Riverside Bayview’s deferential approach avoided. See 474 U. S., at 135, n. 9 (noting that it “is of little

moment” if the Corps’ jurisdiction encompasses some 

wetlands “not significantly intertwined” with other waters 

of the United States). Unlike JUSTICE KENNEDY, I see no 

reason to change Riverside Bayview’s approach—and 

every reason to continue to defer to the Executive’s sensible, bright-line rule. 

V 

As I explained in SWANCC, Congress passed the Clean 

Water Act in response to wide-spread recognition—based

on events like the 1969 burning of the Cuyahoga River in 
Cite as: 547 U. S. ____ (2006) 25 

STEVENS, J., dissenting 

Cleveland—that our waters had become appallingly 

polluted. 531 U. S., at 174–175 (dissenting opinion). The 

Act has largely succeeded in restoring the quality of 

our Nation’s waters. Where the Cuyahoga River was 

once coated with industrial waste, “[t]oday, that location is lined with restaurants and pleasure boat 

slips.” EPA, A Benefits Assessment of the Water 

Pollution Control Programs Since 1972, p. 1–2 (Jan. 

2000), http://www.epa.gov/ost/economics/assessment.pdf. 

By curtailing the Corps’ jurisdiction of more than 30 years,

the plurality needlessly jeopardizes the quality of our 

waters. In doing so, the plurality disregards the deference 

it owes the Executive, the congressional acquiescence in

the Executive’s position that we recognized in Riverside 

Bayview, and its own obligation to interpret laws rather

than to make them. While JUSTICE KENNEDY’s approach

has far fewer faults, nonetheless it also fails to give proper

deference to the agencies entrusted by Congress to implement the Clean Water Act. 

I would affirm the judgments in both cases, and respectfully dissent from the decision of five Members of this 

Court to vacate and remand. I close, however, by noting

an unusual feature of the Court’s judgments in these 

cases. It has been our practice in a case coming to us from

a lower federal court to enter a judgment commanding 

that court to conduct any further proceedings pursuant to

a specific mandate. That prior practice has, on occasion, 

made it necessary for Justices to join a judgment that did 

not conform to their own views.13 In these cases, however, 

while both the plurality and JUSTICE KENNEDY agree that 

—————— 

13See, e.g., Screws v. United States, 325 U. S. 91, 131–134 (1945) 

(Rutledge, J., concurring in result); Turner Broadcasting System, Inc. v. 

FCC, 512 U. S. 622, 674 (1994) (STEVENS, J., concurring in part and 

concurring in judgment); Hamdi v. Rumsfeld, 542 U. S. 507, 553–554 

(2004) (SOUTER, J., concurring in part, dissenting in part, and concurring 

in judgment). 
26 RAPANOS v. UNITED STATES 

STEVENS, J., dissenting 

there must be a remand for further proceedings, their 

respective opinions define different tests to be applied on 

remand. Given that all four Justices who have joined this 

opinion would uphold the Corps’ jurisdiction in both of 

these cases—and in all other cases in which either the 

plurality’s or JUSTICE KENNEDY’s test is satisfied—on 

remand each of the judgments should be reinstated if 

either of those tests is met.14 

—————— 

14 I assume that JUSTICE KENNEDY’s approach will be controlling in

most cases because it treats more of the Nation’s waters as within the 

Corps’ jurisdiction, but in the unlikely event that the plurality’s test is 

met but JUSTICE KENNEDY’s is not, courts should also uphold the Corps’ 

jurisdiction. In sum, in these and future cases the United States may

elect to prove jurisdiction under either test. 
_________________ 

_________________ 

Cite as: 547 U. S. ____ (2006) 1 

BREYER, J., dissenting 

SUPREME COURT OF THE UNITED STATES 

Nos. 04–1034 and 04–1384 

JOHN A. RAPANOS, ET UX., ET AL., PETITIONERS 

04–1034 v. 

UNITED STATES 

JUNE CARABELL ET AL., PETITIONERS 

04–1384 v. 

UNITED STATES ARMY CORPS OF ENGINEERS ET AL. 

ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF 

APPEALS FOR THE SIXTH CIRCUIT 

[June 19, 2006] 

JUSTICE BREYER, dissenting. 

In my view, the authority of the Army Corps of Engineers under the Clean Water Act extends to the limits of 

congressional power to regulate interstate commerce. See 

Solid Waste Agency of Northern Cook Cty. v. Army Corps of 

Engineers, 531 U. S. 159, 181–182 (2001) (SWANCC)

(STEVENS, J., dissenting). I therefore have no difficulty

finding that the wetlands at issue in these cases are within

the Corps’ jurisdiction, and I join JUSTICE STEVENS’ dissenting opinion. 

My view of the statute rests in part upon the nature of the 

problem. The statute seeks to “restore and maintain the 

chemical, physical, and biological integrity of the Nation’s 

waters.” 33 U. S. C. §1251(a). Those waters are so various and so intricately interconnected that Congress might

well have decided the only way to achieve this goal is to

write a statute that defines “waters” broadly and to leave

the enforcing agency with the task of restricting the scope 

of that definition, either wholesale through regulation or 
2 RAPANOS v. UNITED STATES 

BREYER, J., dissenting 

retail through development permissions. That is why I 

believe that Congress, in using the term “waters of the

United States,” §1362(7), intended fully to exercise its 

relevant Commerce Clause powers.

I mention this because the Court, contrary to my view, 

has written a “nexus” requirement into the statute. 

SWANCC, supra, at 167; ante, at 22 (opinion of KENNEDY, 

J.) (“[T]he Corps’ jurisdiction over wetlands depends upon

the existence of a significant nexus between the wetlands 

in question and navigable waters in the traditional 

sense”). But it has left the administrative powers of the 

Army Corps of Engineers untouched. That agency may

write regulations defining the term—something that it has 

not yet done. And the courts must give those regulations 

appropriate deference. Chevron U. S. A. Inc. v. Natural 

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

If one thing is clear, it is that Congress intended the

Army Corps of Engineers to make the complex technical 

judgments that lie at the heart of the present cases (subject to deferential judicial review). In the absence of updated regulations, courts will have to make ad hoc determinations that run the risk of transforming scientific 

questions into matters of law. That is not the system 

Congress intended. Hence I believe that today’s opinions, 

taken together, call for the Army Corps of Engineers to 

write new regulations, and speedily so.