                 FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT


HAWAI‘I WILDLIFE FUND, a Hawaii           No. 15-17447
non-profit corporation; SIERRA CLUB
- MAUI GROUP, a non-profit                  D.C. No.
corporation; SURFRIDER                   1:12-cv-00198-
FOUNDATION, a non-profit                   SOM-BMK
corporation; WEST MAUI
PRESERVATION ASSOCIATION, a
Hawaii non-profit corporation,            ORDER AND
                 Plaintiffs-Appellees,     AMENDED
                                            OPINION
                  v.

COUNTY OF MAUI,
            Defendant-Appellant.


      Appeal from the United States District Court
               for the District of Hawaii
   Susan O. Mollway, Senior District Judge, Presiding

        Argued and Submitted October 12, 2017
             University of Hawaii Manoa

                 Filed February 1, 2018
                Amended March 30, 2018
2         HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

      Before: Mary M. Schroeder, Dorothy W. Nelson,
        and M. Margaret McKeown, Circuit Judges.

                             Order;
                 Opinion by Judge D.W. Nelson


                            SUMMARY*


                       Environmental Law

    The panel filed (1) an order amending its opinion and, on
behalf of the court, denying a petition for rehearing en banc;
and (2) an amended opinion affirming the district court’s
summary judgment rulings finding that the County of Maui
violated the Clean Water Act when it discharged pollutants
from its wells into the Pacific Ocean, and further finding that
the County had fair notice of its violations.

    The panel concluded that the County’s four discrete wells
were “point sources” from which the County discharged
“pollutants” in the form of treated effluent into groundwater,
through which the pollutants then entered a “navigable
water,” the Pacific Ocean. The wells therefore were subject
to National Pollutant Discharge Elimination System
regulation. Agreeing with other circuits, the panel held that
the Clean Water Act does not require that the point source
itself convey the pollutants directly into the navigable water.
The panel held that the County was liable under the Act
because it discharged pollutants from a point source, the

    *
      This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
         HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI               3

pollutants were fairly traceable from the point source to a
navigable water such that the discharge was the functional
equivalent of a discharge into the navigable water, and the
pollutant levels reaching navigable water were more than de
minimis. The panel rejected the argument that the County’s
effluent injections were disposals of pollutants into wells and
therefore exempt from the NPDES permitting requirements.

    The panel also held that the Clean Water Act provided
fair notice, as required by due process, of what conduct was
prohibited.


                         COUNSEL

Michael R. Shebelskie (argued), Hunton & Williams LLP,
Richmond, Virginia; Colleen P. Doyle, Los Angeles,
California; Patrick K. Wong and Richelle M. Thomson,
County of Maui, Wailuku, Maui, Hawaii; for Defendant-
Appellant.

David L. Henkin (argued) and Summer Kupau-Odo,
Earthjustice, Honolulu, Hawaii, for Plaintiffs-Appellees.

David Y. Chung, Thomas A. Lorenzen, Kirsten L. Nathanson,
and Mark Thomson, Crowell & Moring LLP, Washington,
D.C., for Amici Curiae Association of American Railroads,
American Farm Bureau Federation, American Iron and Steel
Institute, American Petroleum Institute, National Association
of Manufacturers, National Mining Association, The
Fertilizer Institute, and Utility Water Act Group.

Shawn Hagerty, Andre Monette, and Rebecca Andrews, Best
Best & Krieger LLP, San Diego, California; Roderick E.
4       HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

Walston, Best Best & Krieger LLP, Walnut Creek,
California; for Amici Curiae Association of California Water
Agencies, California Association of Sanitation Agencies,
California State Association of Counties, International
Municipal Lawyers Association, League of California Cities,
National Association of Clean Water Agencies, National
Association of Counties, National League of Cities, National
Water Resources Association, and Watereuse Association.

Frederick H. Turner, R. Justin Smith, and Aaron P. Avila,
Attorneys; John C. Cruden, Assistant Attorney General;
Environment and Natural Resources Division, United States
Department of Justice, Washington, D.C.; Karyn
Wendelowski, Office of General Counsel, United States
Environmental Protection Agency, Washington, D.C.; for
Amicus Curiae United States.

Nicholas C. Dranias, Assistant Attorney General; Mark
Brnovich, Attorney General; Office of the Attorney General,
Phoenix, Arizona; for Amici Curiae States of Arizona,
Alabama, Alaska, Arkansas, Georgia, Indiana, Kansas,
Louisiana, Missouri, Montana, Nebraska, Nevada, Oklahoma,
South Carolina, Texas, Utah, West Virginia, and Wyoming.
         HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI               5

                          ORDER

    The Opinion filed on February 1, 2018, is amended as
follows:

    1. On slip opinion page 12, footnote 2, the following text
was added to the end of the footnote: <Hence, it does not
affect our analysis that some of our sister circuits have
concluded that groundwater is not a navigable water. See
Rice v. Harken Expl., 250 F.3d 264, 270 (5th Cir. 2001); Vill.
of Oconomowoc Lake v. Dayton Hudson Corp., 24 F.3d 962,
965 (7th Cir. 1994). We are not suggesting that the CWA
regulates all groundwater. Rather, in fidelity to the statute,
we are reinforcing that the Act regulates point source
discharges to a navigable water, and that liability may attach
when a point source discharge is conveyed to a navigable
water through groundwater. Our holding is therefore
consistent with Rice, where the Fifth Circuit required some
evidence of a link between discharges and contamination of
navigable waters, 250 F.3d at 272, and with Dayton Hudson,
where the Seventh Circuit only considered allegations of a
“potential [rather than an actual] connection between ground
waters and surface waters,” 24 F.3d at 965.>

    2. On slip opinion page 19, footnote 3, the following text
was added to the end of the footnote: <Those principles are
especially relevant in the CWA context because the law
authorizes citizen suits to enforce its provisions. See § 1365.
Our approach is firmly grounded in our case law, which
distinguishes between point source and nonpoint source
pollution based on whether pollutants can be “traced” or are
“traceable” back to a point source. See Alaska, 749 F.2d at
558; Ecological Rights, 713 F.3d at 508; supra, at 12–15.>
6       HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

    3. On slip opinion at page 19, the following text replaces
the sentence after the citation to Haw. Wildlife, 24 F. Supp.
3d at 1000: <Here, the Tracer Dye Study and the County’s
concessions conclusively establish that pollutants discharged
from all four wells emerged at discrete points in the Pacific
Ocean, with 64 percent of the wells’ pollutants reaching the
ocean. The Study also traced a southwesterly path from the
wells’ point source discharges to the ocean.>

    With these amendments, Judge McKeown voted to deny
County of Maui’s Petition for Rehearing En Banc. Judge
Schroeder and Judge Nelson recommended denial of petition
for rehearing en banc. The full court has been advised of the
petition for rehearing en banc and no judge of the court has
requested a vote on whether to rehear the matter en banc.

    The petition for rehearing en banc is DENIED. No
further petitions for rehearing or rehearing en banc may be
filed.
        HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI               7

                         OPINION

D.W. NELSON, Senior Circuit Judge:

    The County of Maui (“County”) appeals the district
court’s summary judgment rulings finding the County
violated the Clean Water Act (“CWA”) when it discharged
pollutants from its wells into the Pacific Ocean, and further
finding it had fair notice of its violations. Hawai‘i Wildlife
Fund, Sierra Club - Maui Group, Surfrider Foundation, and
West Maui Preservation Association (“Associations”) urge us
to uphold these rulings. For the reasons set forth below, we
affirm the district court.

                     BACKGROUND

1. The Lahaina Wells and the Effluent Injections

    The County owns and operates four wells at the Lahaina
Wastewater Reclamation Facility (“LWRF”), the principal
municipal wastewater treatment plant for West Maui. Wells
1 and 2 were installed in 1979 as part of the original 1975
plant design, and Wells 3 and 4 were added in 1985 as part of
an expansion project. Although constructed initially to serve
as a backup disposal method for water reclamation, the wells
have since become the County’s primary means of effluent
disposal into groundwater and the Pacific Ocean.

    The LWRF receives approximately 4 million gallons of
sewage per day from a collection system serving
approximately 40,000 people. That sewage is treated at the
Facility and then either sold to customers for irrigation
purposes or injected into the wells for disposal. The County
disposes of almost all the sewage it receives—it injects
8        HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

approximately 3 to 5 million gallons of treated wastewater
per day into the groundwater via its wells.

    That some of the treated effluent then reaches the Pacific
Ocean is undisputed. The County expressly conceded below
and its expert confirmed that wastewater injected into Wells
1 and 2 enters the Pacific Ocean. The Associations submitted
various studies and expert declarations establishing a
connection between Wells 3 and 4 and the ocean. Although
the County quibbles with how much effluent enters the ocean
and by what paths the pollutants travel to get there, it
concedes that effluent from all four wells reaches the ocean.

    The County has known this since the Facility’s inception.
The record establishes the County considered building an
ocean outfall to dispose of effluent directly into the ocean but
decided against it because it would be too harmful to the
coastal waters. It opted instead for injection wells it knew
would affect these waters indirectly. When the Facility
underwent environmental review in February 1973, the
County’s consultant—Dr. Michael Chun—stated effluent that
was not used for reclamation purposes would be injected into
the wells and that these pollutants would then enter the ocean
some distance from the shore. The County further confirmed
this in its reassessment of the Facility in 1991.

    According to the County’s expert, when the wells inject
2.8 million gallons of effluent per day, the flow of effluent
into the ocean is about 3,456 gallons per meter of coastline
per day—roughly the equivalent of installing a permanently-
running garden hose at every meter along the 800 meters of
coastline. About one out of every seven gallons of
groundwater entering the ocean near the LWRF is comprised
of effluent from the wells.
        HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI               9

2. The Tracer Dye Study

    In June 2013, the U.S. Environmental Protection Agency
(“EPA”), the Hawaii Department of Health (“HDOH”), the
U.S. Army Engineer Research and Development Center, and
researchers at the University of Hawaii conducted a study
(the “Tracer Dye Study” or “Study”) on Wells 2, 3, and 4 to
gather data on, among other things, the “hydrological
connections between the injected treated wastewater effluent
and the coastal waters.” The Study involved placing tracer
dye into Wells 2, 3, and 4, and monitoring the submarine
seeps off Kahekili Beach to see if and when the dye would
appear in the ocean.

     The Study concluded “a hydrogeologic connection exists
between . . . Wells 3 and 4 and the nearby coastal waters of
West Maui.” Eighty-four days after injection, tracer dye
introduced to Wells 3 and 4 began to emerge “from very
nearshore seafloor along North Kaanapali Beach,” near
Kahekili Beach Park, about a half-mile southwest of the
LWRF. According to the Study, the effluent travels in this
southwesterly path “due to geologic controls that include a
hydraulic barrier created by valley fills to the northwest.”
The Study found “64 percent of the treated wastewater
injected into [Wells 3 and 4] currently discharges [into the
ocean].” It further concluded “[t]he major discharge areas are
confined to two clusters, only several meters wide, with very
little discharge [occurring] in between and around them.”

    Tracer dye from Well 2 was not detected in the ocean.
But this was because Wells 3 and 4—located between Well
2 and the areas in the ocean where the wastewater
discharges—“inject the majority of effluent,” which likely
diverted the injected wastewater from Well 2 into taking “a
10      HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

different path other than directly towards the submarine
springs” where the wastewater from Wells 3 and 4
discharges. If Well 2 were to receive most of the effluent at
the Facility, that effluent would also take the southwesterly
path taken by the wastewater from Wells 3 and 4. And
“[b]ecause Well 1 is located in very close proximity to Well
2, . . . the [T]racer [S]tudy’s predictions for the fate of
effluent from Well 2 can be used to predict the fate of
effluent from Well 1,” according to the Associations’ expert
Dr. Jean Moran.

3. The District Court’s Summary Judgment Rulings

    The County appeals three of the district court’s summary
judgment rulings. In the first, the district court found the
County liable as to Wells 3 and 4 for discharging effluent
through groundwater and into the ocean without the National
Pollutant Discharge Elimination System (“NPDES”) permit
required by the CWA. Haw. Wildlife Fund v. Cty. of Maui,
24 F. Supp. 3d 980, 1005 (D. Haw. 2014). The court based
its decision on three independent grounds: (1) the County
“indirectly discharge[d] a pollutant into the ocean through a
groundwater conduit,” (2) the groundwater is a “point source”
under the CWA, and (3) the groundwater is a “navigable
water” under the Act. Id. at 993, 999, 1005.

     In its second order, the district court held the County
liable as to Wells 1 and 2 based largely on the same reasons
it found the County liable on Wells 3 and 4. Haw. Wildlife
Fund v. Cty. of Maui, Civil No. 12-00198 SOM/BMK, 2015
WL 328227, at *5–6 (D. Haw. Jan. 23, 2015). The court
acknowledged that no study confirms the “point of entry into
the ocean of flow from [W]ells 1 and 2.” Id. at *2. But it
nonetheless held against the County after “repeatedly
         HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI              11

confirm[ing] at the [summary judgment] hearing . . . that the
County was expressly conceding that pollutants introduced by
the County into [W]ells 1 and 2 were making their way to the
ocean.” Id.

    Finally, the district court found the County could not
claim a due process violation because it had fair notice under
the plain language of the CWA that it could not discharge
effluent via groundwater into the ocean.

   This appeal followed.

                STANDARD OF REVIEW

    The Ninth Circuit “review[s] the district court’s grant or
denial of motions for summary judgment de novo.” Animal
Legal Def. Fund v. U.S. Food & Drug Admin., 836 F.3d 987,
988 (9th Cir. 2016) (citation and internal quotation marks
omitted). “Thus, on appellate review, [the] [Court] employ[s]
the same standard used by the trial court under Federal Rule
of Civil Procedure 56(c).” Id. “As required by that standard,
[the Court] view[s] the evidence in the light most favorable
to the nonmoving party, determine[s] whether there are any
genuine issues of material fact, and decide[s] whether the
district court correctly applied the relevant substantive law.”
Id. at 989 (citation omitted).

                       DISCUSSION

    The Clean Water Act is designed to “restore and maintain
the chemical, physical, and biological integrity of the
Nation’s waters.” 33 U.S.C. § 1251(a). To achieve this
objective, the Act prohibits the “discharge of any pollutant by
any person,” id. § 1311(a), and defines “discharge of a
12       HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

pollutant” as “any addition of any pollutant to navigable
waters from any point source,” id. § 1362(12) (internal
quotation marks omitted). A “point source” is “any
discernible, confined and discrete conveyance, including but
not limited to any . . . well . . . from which pollutants are or
may be discharged.” Id. § 1362(14) (internal quotation marks
omitted). A party who obtains an NPDES permit is exempt
from the general prohibition on point source pollution. Id.
§§ 1311(a), 1342(a)(1). Under these provisions, a party
violates the CWA when it does not obtain such a permit and
“(1) discharge[s] (2) a pollutant (3) to navigable waters
(4) from a point source.” Headwaters, Inc. v. Talent
Irrigation Dist., 243 F.3d 526, 532 (9th Cir. 2001) (citation
omitted).

1. Liability under the CWA

    The County argues the district court erred in concluding
it was liable under the CWA as to all four of its wells. We
disagree.

     a. Point Source Discharges

    Neither side here disputes that each of the four wells
constitutes a “point source” under the CWA. Given the wells
here are “discernible, confined and discrete conveyance[s] . . .
from which pollutants are . . . discharged,” and the plain
language of the statute expressly includes a “well” as an
example of a “point source,” the County could not plausibly
deny the wells are “point source[s]” under the statute.
§ 1362(14) (internal quotation marks omitted). The record
further establishes that from these point sources the County
discharges “pollutants” in the form of treated effluent into
groundwater, through which the pollutants then enter a
         HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI               13

“navigable water[],” the Pacific Ocean.                See id.
§§ 1362(7)–(8), (12), (14). As the pollutants here enter
navigable waters and can be “traced [back] to . . . identifiable
point[s] of discharge,” “[the wells] are subject to NPDES
regulation, as are all point sources” under the plain language
of the CWA. Trs. for Alaska v. E.P.A., 749 F.2d 549, 558
(9th Cir. 1984) (citations omitted).

    That the County’s activities constitute “point source”
discharges becomes clearer once we consider our
jurisprudence on “nonpoint source pollution”: “[Such]
pollution . . . arises from many dispersed activities over large
areas,” “is not traceable to any single discrete source,” and
due to its “diffuse” nature, “is very difficult to regulate
through individual permits.” Ecological Rights Found. v.
Pac. Gas & Elec. Co., 713 F.3d 502, 508 (9th Cir. 2013)
(citations omitted). “The most common example of nonpoint
source pollution is the residue left on roadways by
automobiles” which rainwater “wash[es] off . . . the streets
and . . . carrie[s] along by runoff in a polluted soup [to]
creeks, rivers, bays, and the ocean.” Id. Our cases have
consistently held that such runoff constitutes nonpoint source
pollution unless it is later collected, channeled, and
discharged through a point source. See, e.g., id. (citations
omitted); Envtl. Def. Ctr., Inc. v. U.S. E.P.A., 344 F.3d 832,
841 n.8 (9th Cir. 2003) (citation omitted). Applying these
principles in Ecological Rights, we held that rainwater runoff
carrying pollutants from the defendants’ utility poles to
navigable waters constituted nonpoint source pollution under
the CWA. 713 F.3d at 509 (citations omitted).

    Ours is a different case entirely. Unlike the “millions of
cars” discussed in Ecological Rights, here we have four
“discrete” wells that have been identified and can be
14        HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

“regulate[d] through individual permits.” Id. at 508 (citations
omitted). Furthermore, the automobiles and the utility poles
discussed in Ecological Rights did nothing themselves to
“discretely collect[] and convey[]” the pollutants to a
navigable water, and hence could not constitute “point
source[s]” under § 1362(14). Id. at 508–10 (citations
omitted). The Lahaina Wells, by contrast, collect and inject
pollutants in four discrete wells into groundwater connected
to the Pacific Ocean, thereby “discretely collect[ing] and
convey[ing]” pollutants to a navigable water. Id. at 509
(citations omitted); § 1362(14). The Tracer Dye Study
confirms this connection as to Wells 3 and 4, and the County
conceded as much as to Wells 1 and 2. Given the County
knew of these effects well before the LWRF’s inception, the
record further establishes it “constructed [the wells] for the
express purpose of storing pollutants [and] moving them from
[the Lahaina Facility] to [the Pacific Ocean].” Ecological
Rights, 713 F.3d at 509 (citations omitted).1 This is simply
not a case of “nonpoint source pollution . . . caused primarily
by rainfall around activities that employ or create pollutants,”
where the resulting “runoff [can]not be traced to any
identifiable point of discharge.” Alaska, 749 F.2d at 558


     1
       We do not mean to suggest that a CWA violation requires some
form of intent. It does not. See Comm. to Save Mokelumne River v. East
Bay Mun. Util. Dist., 13 F.3d 305, 309 (9th Cir. 1993) (recognizing CWA
“categorically prohibits any discharge of a pollutant from a point source
without a permit” (citations omitted)); accord Sierra Club v. ICG Hazard,
LLC, 781 F.3d 281, 284 (6th Cir. 2015) (recognizing “regime of strict
liability” under the CWA (citation and internal quotation marks omitted));
Piney Run Pres. Ass’n v. Cty. Comm’rs of Carroll Cty., 268 F.3d 255, 265
(4th Cir. 2001) (same). But the County’s purpose in constructing the
wells certainly informs whether they are “conveyance[s]” under the CWA,
§ 1362(14), and hence, regulable point sources under the statute. See
Ecological Rights, 713 F.3d at 509 (citations omitted).
          HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI                        15

(citing United States v. Earth Scis., Inc., 599 F.2d 368, 373
(10th Cir. 1979)). As the “[County’s] activities release[d]
pollutants from . . . discernible conveyance[s]” to navigable
waters, the County is liable under the CWA. Id. (citations
omitted).

    b. Indirect Discharges

    The County contends, however, that under the CWA, it is
not sufficient to focus exclusively on the original pollutant
source to determine whether an NPDES permit is needed and
that how pollutants travel from the original point source to
navigable waters matters. More specifically, the County
contends the point source itself must convey the pollutants
directly into the navigable water under the CWA. As the
wells here discharge into groundwater, and then indirectly
into the Pacific Ocean, the County asserts they do not come
within the ambit of the statute.2




    2
      We assume without deciding the groundwater here is neither a point
source nor a navigable water under the CWA. Hence, it does not affect
our analysis that some of our sister circuits have concluded that
groundwater is not a navigable water. See Rice v. Harken Expl., 250 F.3d
264, 270 (5th Cir. 2001); Vill. of Oconomowoc Lake v. Dayton Hudson
Corp., 24 F.3d 962, 965 (7th Cir. 1994). We are not suggesting that the
CWA regulates all groundwater. Rather, in fidelity to the statute, we are
reinforcing that the Act regulates point source discharges to a navigable
water, and that liability may attach when a point source discharge is
conveyed to a navigable water through groundwater. Our holding is
therefore consistent with Rice, where the Fifth Circuit required some
evidence of a link between discharges and contamination of navigable
waters, 250 F.3d at 272, and with Dayton Hudson, where the Seventh
Circuit only considered allegations of a “potential [rather than an actual]
connection between ground waters and surface waters,” 24 F.3d at 965.
16       HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

     The County first cites Alaska, where we held that point
source pollution occurs when “the pollution reaches the water
through a confined, discrete conveyance,” regardless of “the
kind of pollution” at issue or “the activity causing [it].” Id. at
558 (citation omitted). As the effluent here reaches the
Pacific Ocean “through” groundwater—a nonpoint source—
the County contends it is not liable under the CWA. The
County reads Alaska out of context. First, we never
addressed in Alaska whether a polluter may be liable under
the CWA for indirect discharges because the issue was not
before us. See id. Furthermore, when we stated the
“pollution [must] reach[] the water through a confined,
discrete conveyance,” we were merely stating the pollution
must come “from a discernible conveyance” as opposed to
some “[un]identifiable point of discharge.” Id. (emphasis
added) (citations omitted). As the “discharge water [there]
[was] released from a sluice box, a confined channel within
the statutory definition,” the activity came within the ambit of
the CWA. Id. (emphasis added). This case is no
different—the effluent comes “from” the four wells and
travels “through” them before entering navigable waters. Id.
It just also travels through groundwater before entering the
Pacific Ocean.

     A more recent case Greater Yellowstone Coalition v.
Lewis supports the Associations’ contention that the CWA
governs indirect discharges. We held there that precipitation
flowing into pits containing “newly extracted waste rock,”
“filter[ed]” hundreds of feet underground, and “eventually
entering the surface water” did not constitute point source
pollution under the CWA. 628 F.3d 1143, 1147, 1153 (9th
Cir. 2010) (citation omitted). The “pits that collect[ed] the
waste rock [did] not constitute point sources” because “there
[was] no confinement or containment of the [polluted] water”
         HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI                17

before it entered navigable waters, as prohibited by the
statute. Id. We also concluded, however, that precipitation
flowing into a “stormwater drain system” before “enter[ing]
the ground and, eventually, surface water” constituted a point
source discharge—the “stormwater system [was] exactly the
type of collection or channeling contemplated by the CWA.”
Id. at 1152.

    The wells here are more akin to the stormwater drain
system in Greater Yellowstone than they are to the pits that
collected the waste rock. Unlike the pits that “[did] not
constitute points sources within the meaning of the CWA,”
the wells here “confine[] [and] contain[] . . . the [effluent]”
before discharging it “[into] the ground and, eventually,
surface water.” Id. at 1152–53. And it was of no import to us
in Greater Yellowstone that the pollutants—as here—had to
travel through the ground before “eventually, [entering]
surface water.” Id. at 1152. The Court was only concerned
with whether there was a point source from which the
defendant discharged the pollutants. As the stormwater drain
system constituted this point source, the Court concluded the
defendant was required to “obtain[] the requisite . . .
certification for that system.” Id. at 1153. As the County
also discharges its pollutants from a point source, it, too, must
obtain an NPDES permit under the CWA.

    Our sister circuits agree that an indirect discharge from a
point source to a navigable water suffices for CWA liability
to attach. In Concerned Area Residents for Environment v.
Southview Farm, the Second Circuit held “[t]he collection of
liquid manure into tankers and their discharge on fields from
which the manure directly flows into navigable waters are
point source discharges under the case law.” 34 F.3d 114,
119 (2d Cir. 1994). Regardless of whether the field itself was
18       HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

a point source, the court concluded there was a “point source
discharge[]” under the CWA because (1) the pollutant itself
was released from the tanker, a point source, and (2) there
was a “direct[]” connection between the field and the
navigable water. See id. Both elements are present here.
The wells are point sources under the statute, § 1362(14), and
the Tracer Dye Study along with the County’s concessions
establish an undeniable connection between the wells and the
Pacific Ocean. The Study establishes effluent injected into
the wells travels a southwesterly path from the Facility,
appearing in submarine springs only a half-mile away.

    Furthermore, in Sierra Club v. Abston Construction, the
Fifth Circuit recognized that the “ultimate question [as to
CWA liability] is whether pollutants [are] discharged from
‘discernible, confined, and discrete conveyance(s)’ either by
gravitational or nongravitational means.” 620 F.2d 41, 45
(5th Cir. 1980). It went on to hold that “[s]ediment basins
dug by the miners and designed to collect sediment are . . .
point sources . . . even though the materials [are] carried
away from the basins by gravity flow of rainwater.” Id.
(emphasis added). “Gravity flow, resulting in a discharge
into a navigable body of water, may be part of a point source
discharge if the miner at least initially collected or channeled
the water and other materials.” Id. (emphasis added). That
is what occurred here. The County “initially collected [and]
channeled” the pollutants in its wells and injected them into
the ground, where they were “carried away from the [wells]
by the gravity flow of [ground]water.” Id. And based on the
overwhelming evidence in this case establishing a connection
between the wells and the Pacific Ocean, it cannot be
disputed the wells are “reasonably likely to be the means by
which [the] [effluent] [is] ultimately deposited into a
navigable body of water.” Id. Indeed, the County has known
         HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI               19

since the LWRF’s inception that effluent from the wells
would eventually reach the ocean some distance from the
shore. That the groundwater plays a role in delivering the
pollutants from the wells to the navigable water does not
preclude liability under the statute. See id.

    The Second Circuit further recognized the indirect
discharge theory in Peconic Baykeeper, Inc. v. Suffolk
County, where it rejected the district court’s conclusion that
“because the trucks and helicopters discharged pesticides into
the air, any discharge was indirect, and thus not from a point
source.” 600 F.3d 180, 188 (2d Cir. 2010). As the pesticides
there were “discharged ‘from’ the source, and not from the
air,” the court concluded the “spray apparatus . . . attached to
[the] trucks and helicopters” constituted a point source under
the CWA. Id. at 188–89 (emphasis added). The Ninth
Circuit has similarly held discharges through the air can
constitute “point source pollution” under the statute. League
of Wilderness Def./Blue Mountains Biodiversity Project v.
Forsgren, 309 F.3d 1181, 1185, 1192–93 (9th Cir. 2002).

    But accepting the County’s position—that pollutants must
“travel via a ‘confined and discrete conveyance’” to
navigable waters for CWA liability to attach—would
necessarily preclude liability in cases such as Peconic
Baykeeper and League of Wilderness. The pollutants in both
cases traveled to navigable waters via the air, and not via the
point sources from which they were released. See Peconic
Baykeeper, 600 F.3d at 188; League of Wilderness, 309 F.3d
at 1185. Taken to its logical conclusion, the County’s theory
would only support liability in cases where the point source
itself directly feeds into the navigable water—e.g., via a pipe
or a ditch. That the circuits have recognized CWA liability
20       HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

where such a direct connection does not exist counsels
against accepting the County’s theory.

     Indeed, writing for the plurality in Rapanos v. United
States, Justice Scalia recognized the CWA 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.’” 547 U.S. 715, 743 (2006) (plurality
opinion) (emphasis in original) (quoting §§ 1311(a),
1362(12)(A)). He further recognized that “from the time of
the CWA’s enactment, lower courts have held that the
discharge 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.” Id. (emphasis in original)
(citations omitted). In support of his “‘indirect discharge’
rationale,” Justice Scalia cited Concerned Area Residents,
where, as described above, the Second Circuit held the
discharge of manure from point sources onto fields (which
were not necessarily point sources themselves) and eventually
into navigable waters constituted point source discharges
under the CWA. Id. at 744.

    Although the Court in Rapanos splintered on other issues,
no Justice disagreed with the plurality opinion that the CWA
holds liable those who discharge a pollutant from a defined
point source to the ocean. Justice Kennedy’s opinion
concurring in the judgment objected only to the plurality
opinion’s creation of certain limitations on the Executive
Branch’s authority to enforce the CWA’s environmental
purpose and statutory mandate. Id. at 778. Similarly, the
four-Justice dissent cited the CWA’s prohibition of “any
addition of any pollutant to navigable waters from any point
         HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI               21

source” as strong evidence of the law’s wide sweep, and
disagreed with the plurality opinion’s creation of two
limitations on CWA enforcement. Id. at 787, 800–06
(Stevens, J., dissenting).

    In past cases, we have recognized Justice Kennedy’s
concurrence in Rapanos, not Justice Scalia’s plurality
opinion, as controlling. But we have only done so in the
context of “determin[ing] whether a wetland that is not
adjacent to and does not contain a navigable-in-fact water is
subject to the CWA.” United States v. Robertson, 875 F.3d
1281, 1288–89 (9th Cir. 2017) (citations omitted); see also N.
Cal. River Watch v. City of Healdsburg, 496 F.3d 993, 995
(9th Cir. 2007). As this is not a case about wetlands, and we
do not decide whether groundwater is a “navigable water”
under the statute, we do not apply Justice Kennedy’s
concurrence here, and consider Justice Scalia’s plurality
opinion only for its persuasive value, United States v. Brobst,
558 F.3d 982, 991 (9th Cir. 2009) (citing CTS Corp. v.
Dynamics Corp. of Am., 481 U.S. 69, 81 (1987)) (internal
quotation marks omitted). See S.F. Baykeeper v. Cargill Salt
Div., 481 F.3d 700, 707 (9th Cir. 2007) (“No Justice [in
Rapanos], even in dictum, addressed the question whether all
waterbodies with a significant nexus to navigable waters are
covered by the Act.”).

     Justice Scalia’s plurality opinion demonstrates the County
is reading into the statute at least one critical term that does
not appear on its face—that the pollutants must be discharged
“directly” to navigable waters from a point source. As “the
plain language of a statute should be enforced according to its
terms,” we therefore reject the County’s reading of the CWA
and affirm the district court’s rulings finding the County
22        HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

liable under the Act. ASARCO, LLC v. Celanese Chem. Co.,
792 F.3d 1203, 1210 (9th Cir. 2015) (citations omitted).

    We hold the County liable under the CWA because
(1) the County discharged pollutants from a point source,
(2) the pollutants are fairly traceable from the point source to
a navigable water such that the discharge is the functional
equivalent of a discharge into the navigable water, and (3) the
pollutant levels reaching navigable water are more than de
minimis.3 The second point in particular is an important one.
We therefore disagree with the district court that “liability
under the Clean Water Act is triggered when pollutants reach
navigable water, regardless of how they get there.” Haw.
Wildlife, 24 F. Supp. 3d at 1000 (emphasis added). Here, the
Tracer Dye Study and the County’s concessions conclusively
establish that pollutants discharged from all four wells
emerged at discrete points in the Pacific Ocean, with
64 percent of the wells’ pollutants reaching the ocean. The
Study also traced a southwesterly path from the wells’ point
source discharges to the ocean. We leave for another day the
task of determining when, if ever, the connection between a

     3
       The EPA as amicus curiae proposes a liability rule requiring a
“direct hydrological connection” between the point source and the
navigable water. Regardless of whether that standard is entitled to any
deference, it reads two words into the CWA (“direct” and “hydrological”)
that are not there. Our rule adopted here, by contrast, better aligns with
the statutory text and requires only a “fairly traceable” connection,
consistent with Article III standing principles. See, e.g., Spokeo, Inc. v.
Robins, 136 S. Ct. 1540, 1547 (2016). Those principles are especially
relevant in the CWA context because the law authorizes citizen suits to
enforce its provisions. See § 1365. Our approach is firmly grounded in
our case law, which distinguishes between point source and nonpoint
source pollution based on whether pollutants can be “traced” or are
“traceable” back to a point source. See Alaska, 749 F.2d at 558;
Ecological Rights, 713 F.3d at 508; supra, at 12–15.
         HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI                23

point source and a navigable water is too tenuous to support
liability under the CWA.

    c. Disposals of Pollutants into Wells

    Finally, the County contends its effluent injections are not
discharges into navigable waters but “disposal[s] of pollutants
into wells,” and that the Act categorically excludes well
disposals from the permitting requirements of § 1342. See,
e.g., § 1342(b)(1)(D). As the County urges a “construction
that the statute on its face does not permit,” we “reject” it
here. Carson Harbor Vill., Ltd. v. Unocal Corp., 270 F.3d
863, 881 (9th Cir. 2001) (citation and internal quotation
marks omitted).

    The County first relies on § 1342(b), which permits the
EPA to delegate CWA authority to “each State desiring to
administer its own permit program for discharges into
navigable waters within its jurisdiction.” So long as the State
“submit[s] to the Administrator a full and complete
description of [its] program” and “a statement . . . that the
laws of [the] State . . . provide adequate authority to carry out
the described program,” the State may “issue [NPDES]
permits which[,] [among other things] control the disposal of
pollutants into wells.” § 1342(b)(1)(D) (emphasis added).
The County contends based on this language the NPDES
permitting requirements do not apply at all to well disposals.
Not so. The plain language of the statute clearly permits
States to issue NDPES permits for well disposals, and such
permits are required only for “discharges into navigable
waters.” Id. § 131242(b); see also id. § 1342(a)(1). The
provision furthermore makes no judgment about whether a
“disposal” always constitutes a “discharge” requiring a
NPDES permit. Indeed, only when a “disposal” is also a
24       HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

“discharge” is a permit required. See Inland Steel Co. v.
E.P.A., 901 F.2d 1419, 1422 (7th Cir. 1990) (noting
§ 1342(b)(1)(D) “was not intended to authorize [States to]
regulat[e] . . . all wells used to dispose of pollutants,
regardless of absence of any effects on navigable waters”
(emphasis in original)).

    The County also argues that under § 1342(b)(1)(D), only
the State, not the EPA, has authority to regulate well
disposals. This Court, however, has already concluded the
Act does not “expressly grant[] to the EPA or [the
administering] state agency the exclusive authority to decide
whether [there is a CWA violation],” even while recognizing
§ 1342 “suspend[s] the availability of federal NPDES permits
once a state-permitting program has been submitted and
approved by the EPA.” Ass’n to Protect Hammersley, Eld,
and Totten Inlets v. Taylor Res., Inc., 299 F.3d 1007, 1010–12
(9th Cir. 2002) (citing § 1342(c)(1)). That the administering
state agency, HDOH, has “cho[sen] to sit on the sidelines . . .
is not a barrier to a citizen’s otherwise proper federal suit to
enforce the Clean Water Act” and does not somehow “divest
[this Court] of jurisdiction” over this case. Id. at 1012; see
also Cmty. Ass’n for Restoration of the Env’t v. Henry Bosma
Dairy, 305 F.3d 943, 949–50 (9th Cir. 2002) (“Under the
CWA[,] private citizens may sue any person alleged to be in
violation of the conditions of an effluent standard or
limitation under the Act or of an order issued with respect to
such a standard or limitation by the Administrator of the
[EPA] or any state.” (citation omitted)).

    The County next relies on § 1314(f)(2)(D), which “directs
the [EPA] to give States information on the evaluation and
control of [nonpoint source] ‘pollution resulting from . . . [the
disposal of pollutants in wells].’” S. Fla. Water Mgmt. Dist.
         HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI              25

v. Miccosukee Tribe of Indians, 541 U.S. 95, 106 (2004)
(citing and quoting § 1314(f)(2)). According to the County,
§ 1314(f)(2)(D) affirmatively establishes disposals into wells
constitute nonpoint source pollution and that it need not
obtain NPDES permits under the CWA. But the Supreme
Court itself acknowledged in South Florida that while
§ 1314(f)(2) listed a variety of circumstances constituting
“nonpoint source[] [pollution]”—including well
disposals—the provision “does not explicitly exempt [these]
nonpoint pollution sources from the NPDES program if they
also fall within the ‘point source’ definition.” Id. (emphasis
added). Consistent with our reading of § 1342(b)(1)(D), the
implication here is that well disposals do not always
constitute nonpoint source pollution. If pollutants from those
wells are discharged into a navigable water from a discrete
source, that is point source pollution, and the polluter must
obtain an NPDES permit if it wants to avoid liability under
the CWA. See §§ 1311(a), 1342(a)(1).

     The CWA’s definition of “pollutant” also supports this
reading. See § 1362(6)(B). Under the Act, “[t]his term
[excludes] . . . water derived in association with oil or gas
production and disposed of in a well, if [1] the well used
either to facilitate production or for disposal purposes is
approved by authority of the State in which the well is
located, and [2] such State determines that such injection or
disposal will not result in the degradation of ground or
surface water resources.” Id. (emphasis added). By contrast,
pollutants “disposed of in . . . well[s]” that “alter the water
quality” of “surface water[s]” are “subject to NPDES
permitting requirements.” N. Plains Res. Council v. Fid.
Expl. & Dev. Co., 325 F.3d 1155, 1161–62 (9th Cir. 2003)
(citing § 1362(6)(B)). Section 1362(6)(B), therefore,
confirms that contrary to the County’s contentions, the CWA
26       HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

does not categorically exempt all well disposals from the
NPDES requirements. “Were we to conclude otherwise,” and
create out of whole cloth a categorical exemption for well
disposals, we would improperly amend the statute and
“undermine the integrity of [the CWA’s] prohibitions.” Id.
at 1162 (citation and internal quotation marks omitted). We
decline to do so here.

2. Fair Notice

    “Due process requires that [a statute] provide fair notice
of what conduct is prohibited before a sanction can be
imposed.” United States v. Approximately 64,695 Pounds of
Shark Fins, 520 F.3d 976, 980 (9th Cir. 2008) (citation and
internal quotation marks omitted). “To provide sufficient
notice, a statute . . . must give the person of ordinary
intelligence a reasonable opportunity to know what is
prohibited so that he may act accordingly.” Id. (citing
Grayned v. City of Rockford, 408 U.S. 104, 108 (1972))
(internal quotation marks omitted). If the “[p]lain [l]anguage
of the [s]tatute” is “sufficiently clear to warn a party about
what is expected,” a court may find the party had “fair notice”
under the due process clause. Id.; see also Garvey v. Nat’l
Transp. Safety Bd., 190 F.3d 571, 584 (D.C. Cir. 1999)
(finding the defendant had “fair notice” based on “plain
language” of regulation).

    In determining whether there has been fair notice, this
Court must “first look to the language of the statute itself.”
Shark Fins, 520 F.3d at 980 (citation omitted). Here, the
Clean Water Act prohibits the “discharge of any pollutant by
any person.” § 1311(a). The Act defines “discharge of a
pollutant” as “any addition of any pollutant to navigable
waters from any point source.” Id. § 1362(12) (internal
         HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI               27

quotation marks omitted). A “point source” is “any
discernible, confined and discrete conveyance, including but
not limited to any . . . well . . . from which pollutants are or
may be discharged.” Id. § 1362(14) (internal quotation marks
omitted). Finally, there is an exception to the general
prohibition on point source pollution if a party obtains an
NPDES permit. Id. §§ 1311(a), 1342(a)(1).

    It is undisputed the County “add[s] . . . pollutants”—
treated effluent—“to navigable waters”—the Pacific Ocean—
“from . . . point source[s]”—its four injection wells. See id.
§§ 1362(6), (12), (14). As its actions fall squarely within the
“[p]lain [l]anguage of the [s]tatute,” we conclude the County
had “fair notice” its actions violated the CWA. See Shark
Fins, 520 F.3d at 980; Garvey, 190 F.3d at 584; Lee v. Enter.
Leasing Co.-West, LLC, 30 F. Supp. 3d 1002, 1012 (D. Nev.
2014) (finding “reasonable reading of the statute . . . afforded
[the] [d]efendants fair notice that their conduct was at risk”).

    But the County contends it did not have “fair notice”
because the statutory text can be fairly read to exclude the
wells from the NPDES permit requirements. It argues again
that pollution via its wells and the groundwater is nonpoint
source pollution not subject to the CWA’s prohibitions. Even
so, “due process does not demand unattainable feats of
statutory clarity.” Planned Parenthood of Cent. and N. Ariz.
v. State of Ariz., 718 F.2d 938, 948 (9th Cir. 1983) (citation
and internal quotation marks omitted). That there is a
“difference[] of opinion” on “the precise meaning of [the
CWA]” is “[]not . . . enough to render [it]” violative of the
due process clause. Id.

   The County further contends it did not have “fair notice”
because HDOH—the state agency tasked with administering
28       HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI

the NPDES permit program—has maintained an NPDES
permit is unnecessary for the wells. The County does not
describe HDOH’s position accurately. As late as April 2014,
HDOH stated in a letter to the County it was still “in the
process of determining if an NPDES permit is applicable” to
the wells. That HDOH has not solidified its position on the
issue does not affirmatively demonstrate it believes the
permits are unnecessary, as the County contends. And the
fact that the County “has been unable to receive an
interpretation of the [CWA] from . . . [HDOH] officials
administering the program” is also “[]not . . . enough to
render [enforcement of the CWA]” unconstitutional. Id. As
a “reasonable person would [have] underst[oo]d the [CWA]”
as prohibiting the discharges here, enforcement of the statute
does not violate the due process clause. Id. at 948–49; see
also Shark Fins, 520 F.3d at 980 (holding liability would
attach if “regulation is . . . sufficiently clear to warn a party
about what is expected of it” (citation and internal quotation
marks omitted)).

                       CONCLUSION

    At bottom, this case is about preventing the County from
doing indirectly that which it cannot do directly. The County
could not under the CWA build an ocean outfall to dispose of
pollutants directly into the Pacific Ocean without an NPDES
permit. It cannot do so indirectly either to avoid CWA
liability. To hold otherwise would make a mockery of the
CWA’s prohibitions. Under the circumstances of this case,
we therefore affirm the district court’s summary judgment
rulings finding the County discharged pollutants from its
        HAWAI‘I WILDLIFE FUND V. CTY. OF MAUI          29

wells into the Pacific Ocean, in violation of the CWA, and
further finding the County had fair notice of what was
prohibited.

   AFFIRMED.
