Opinion by Judge PREGERSON; Dissent by Judge KLEINFELD.
ORDER
The opinion and dissent filed December 10, 1993 is withdrawn.
OPINION
PREGERSON, Circuit Judge:
Northwest Environmental Advocates and Nina Bell (“NWEA”) appeal the district court’s judgment in favor of Portland on their claims that the City is violating the Clean Water Act (“CWA”), 33 U.S.C. § 1251 et seq. On April 16, 1991, NWEA filed suit in the district court alleging that Portland’s practice of discharging raw sewage during times of precipitation from 54 outfall points was not covered by a permit and that the practice had caused and was continuing to cause violations of Oregon’s water quality standards. After a trial on the written record, the district court held that (1) the contested discharge points were covered by Portland’s pollution permit, and (2) the court lacked jurisdiction to consider NWEA’s water quality violation claims.
In Northwest Environmental Advocates v. City of Portland, 11 F.3d 900 (9th Cir.1993) (Northwest), we affirmed. We held that the contested discharge points were covered by Portland’s pollution permit, id. at 903-06, and we held that Northwest Environmental Advocates lacked standing to bring a citizen [981]*981suit under § 505(a)(1) of the Clean Water Act, 33 U.S.C. § 1365(a)(1), to enforce water quality standards contained in Portland’s permit. Id. at 906-11. On December 28, 1993, NWEA filed a petition for rehearing with suggestion for rehearing en banc. While this petition was still pending, the Supreme Court decided PUD No. 1 of Jefferson County v. Washington Department of Ecology, — U.S. -, 114 S.Ct. 1900, 128 L.Ed.2d 716 (1994) (Jefferson County).1
Jefferson County cast into considerable doubt our holding in Northwest that citizens do not have standing under the Clean Water Act to enforce water quality standards unless they have been translated into end-of-pipe effluent limitations. In light of Jefferson County and upon reconsideration of our prior opinion in Northwest, we now vacate that opinion, 11 F.3d at 900-913, and issue the following opinion.
I. BACKGROUND
A. The Portland Sewage Treatment System
At issue is the operation of the Portland sewer system. Portland operates a sewage treatment system that includes a network of combined sewage and stormwater pipes. Although the construction of these combined sewer pipes was discontinued in 1962, approximately 70% of the City’s sewers remain combined sewers. Supp.E.R. 21. The effluent flowing in the system ideally is intercepted and transported to the Columbia Boulevard Treatment Plant where it is treated and then discharged into the Columbia River through two outfalls (Nos. 001 and 002). The interceptors can carry only “‘three times [the] average dry weather flow5 ” of effluent to the treatment plant. Sunnarborg Affl, Supp.E.R. 21. When the flow exceeds the plant’s capacity, as can occur during periods of precipitation, the effluent is released untreated through a system of combined sewer overflow (CSO) outfalls in what is termed a CSO event. There are between 50 and 80 CSO events every year in Portland. E.R. 216; see also Bureau of Environmental Ser-viees, City of Portland, Columbia Slough Planning Study Background Report (1989) (there are between 67 and 79 CSO events per year in the Columbia Slough).
Portland has 54 CSO outfalls; 12 drain into the Columbia Slough and 42 drain into the Willamette River. These waterways and their environs are used by Portland residents for recreation, including water contact activities such as boating. The release of untreated sewage into such public waters can present health risks. See National Combined Sewer Overflow Control Strategy, 54 Fed.Reg. 37370, 37371 (1989) (“CSOs have been shown to have severe adverse impacts on human health under certain conditions.”). Appellants have supplied both anecdotal and scientific evidence of the polluted nature of the Willamette River and the Columbia Slough, especially during and immediately after CSO events. See, e.g., Portland’s Response to NWEA’s Interrogatories, E.R. 119; Thutt Affl., E.R. 159-178; Pratt Affl., E.R. 20.
Abatement of CSO events is not easy. It has been estimated that to solve the problem in Portland alone will cost between $500 million and $1.2 billion dollars. E.R. 221. Estimates for the entire nation are between $70 billion and $109 billion dollars. Environmental Groups Call for Effort to Deal with Combined Sewer Problems, 23 Env.Rptr. (BNA) 13 (1992) (upgrades could start at between $70 and $80 billion dollars); Combined Sewer Overflow Problems Demand New Approach, Local Officials Say, 20 Env. Rptr. (BNA) 1939 (1990) (costs could be as high as $109 billion).
B. Proceedings in the District Court
On February 1, 1991 NWEA gave written notice to Portland, the EPA Administrator, the State of Oregon, and the EPA Regional Administrator of its intent to file suit in the district court challenging the legality of the CSO discharges. Complaint, E.R. 9. In April 1991, after the required 60 day notice period, NWEA filed this action.
[982]*982The crux of the NWEA complaint was that the 54 CSO outfalls being used regularly by the City were not covered by the City’s 1984 National Pollution Discharge Elimination System (NPDES) permit. Because unper-mitted discharges of pollutants are illegal, NWEA argued the City was violating the CWA. Even if the CSOs were covered by the permit, NWEA argued that the discharges violated Oregon water quality standards and therefore violated a condition of the Permit. These violations were ongoing and likely to continue. NWEA prayed for injunctive relief and civil penalties. Complaint, E.R. 10-11.
The 1984 permit was to expire in July 1989. However it remained in effect until Portland and the Oregon Department of Environmental Quality (DEQ)2 were able to complete the renewal process and agree on the terms of a new permit. DEQ forwarded a draft of a proposed renewal permit to Portland in December 1990. This draft permit required the City to “meet water quality standards at all discharge points, including CSOs,.... ” Because Portland could not meet the five year time table set forth in the proposed renewal permit, id., the parties determined that a compliance order separate from the renewal permit, and requiring eventual abatement of all CSO events, was appropriate. After a period of Notice and Comment, Portland and the DEQ came to an agreement in August 1991. Under that settlement, Portland’s new permit specifically listed the CSOs as permitted discharge points. In addition to the permit, the parties entered into a stipulation and final order (SFO) in which Portland agreed to replace the CSO system within the next 20 years.
Once these negotiations had been completed, Portland filed a motion to dismiss and the parties filed cross-motions for summary judgment. The court bifurcated the proceedings; first it would address whether Portland could be held liable for violations of the CWA, and then if necessary, determine whether violations had occurred and impose any necessary penalties. The parties stipulated to a trial of the liability phase on the summary judgment submissions, allowing the eourt to decide questions of fact as well as questions of law. Amended Opinion, E.R. 73.
After reviewing the submissions the district court issued an opinion and judgment. It later filed an amended opinion which was essentially the same as the original. The court found that Portland’s 54 CSOs were covered by the 1984 NPDES permit, and thus that the City was not in violation of the Act for allowing unpermitted discharges. It also rejected NWEA’s claim that Portland would nonetheless be liable for violating Oregon’s water quality standards because the CWA did not confer federal jurisdiction to entertain citizen suits to enforce state water quality standards.
II. ANALYSIS
A. Does the 1984 Permit Cover the CSOs?
In the court below, NWEA argued that Portland had violated and continued to violate the CWA by discharging through unper-mitted outfalls. The district court found otherwise, holding that the relevant NPDES discharge permit authorized CSO events under specific circumstances. NWEA asserts that the district court erred in so interpreting the permit.
We review the district court’s interpretation of the 1984 permit as we would the interpretation of a contract or other legal document. When reviewing a district court’s interpretation of such a writing, the court reviews de novo the determination of whether it is ambiguous. In re U.S. Fin. Sec. Litig., 729 F.2d 628, 632 (9th Cir.1984). Interpretation of an unambiguous writing is also a question of law subject to de novo review. Culinary & Service Employees Union, Local 555 v. Hawaii Employee Ben. Admin. Inc., 688 F.2d 1228, 1230 (9th Cir.1982). If the court must look to extrinsic evidence in order to interpret a writing, its findings of fact are reviewed for clear error. U.S. Fin. Sec., 729 F.2d at 632; Culinary & Service Employees Union, 688 F.2d at 1230; In re Agricultural Research & Technology Group, Inc., 916 F.2d 528, 537 (9th Cir.1990).
[983]*983NWEA argued in the court below that the 1984 permit covered only two point sources, outfalls 001 and 002 from the treatment plant.3 The 1984 permit expressly “covers” only two point sources, outfalls 001 and 002 from the treatment plant. These outfalls are listed on the first page of the permit as the “SOURCES COVERED BY THIS PERMIT.” E.R. 222. The 54 CSOs are not listed in this section. The first page of the permit also states that the receiving waterway for these discharges is the Columbia River. The Willamette River and the Columbia Slough are not mentioned.
Immediately below the section listing “SOURCES COVERED,” the permit provides a description of the activities that are covered by the permit. This section, “PERMITTED ACTIVITIES,” states that Portland is authorized to “operate a waste water collection, treatment, control and disposal system and discharge to public waters adequately treated waste waters only from the authorized discharge point or points established in Schedule A-” E.R. 222 (emphasis added). Schedule A provides the effluent limitations for outfalls 001 and 002. More importantly, however, it provides that:
The permittee shall provide interception of at least three times the dry weather flow before discharge shall occur at any diversion structure. The overflow from these diversion structures shall be minimized and/or eliminated as much as practicable during the water recreation season (June 1 to October 31).4
E.R. 228. Thus, on the face of the permit it appears that CSO events were considered to be a “permitted activity.” Finally, Schedule C provides that the City must “continue to work toward the separation of sanitary sewage and storm water in presently developed areas in which this method is cost effective.” E.R. 224.
NWEA contends that the court should only heed the first portion of the permit listing covered sources.5 Because the CSOs are not specifically listed on page one as permitted sources, NWEA argues, they must not have been encompassed by the permit and are therefore illegal. To follow this reasoning would require the court to read the references to diversion structures out of the permit altogether. The limitations on the frequency of CSO events and the requirement that Portland work towards upgrading its sewer system would then constitute mere surplusage.
The 1984 permit is clear on its face in permitting CSO events under specified conditions. The description of permitted activities specifically allows Portland to operate a sewage system and to discharge through two separate sets of discharge points, those listed on page one as authorized discharge points, and those described and listed in Schedule A.
The extrinsic evidence presented to the district court only strengthens this conclusion. The parties each offered evidence, in the form of affidavits and other documentary evidence, to support their respective understandings of the 1984 permit. NWEA relied mainly on four documents to support the position that the CSOs were not, and had never been, permitted. The first was a letter from W.C. Gaffi, Portland’s Chief Engineer, to DEQ in 1988. Gaffi stated that “the City supports ODEQ’s position to permit the CSO outfalls through a modification to the existing treatment permit. This approach should achieve the same goal as individual CSO permits and reduce the administrative cost of doing so.” E.R. 278. The second document was an October 1990 memorandum from two [984]*984members of the Portland Bureau of Environmental Services. In this memo, Linda Mac-Pherson and Dave Kliewer indicated the need to set up a “discussion to determine if the CSOs are going to be permitted or not?” E.R. 279. The third is an undated memorandum in which a DEQ employee wrote that “the potential exists for permitting both the storm and combined sewer discharges.” E.R. 191. NWEA argues that these three documents imply that the CSOs were not covered under the 1984 permit, because if they were, there would be no need to address including them in future permits.
Finally, NWEA offered a DEQ policy statement entitled “Strategy for Regulating Combined Sewer Overflows.”6 The report states that “none of these outfalls [the CSOs] are covered by a permit, however, all are proposed to be addressed in the Portland-Columbia Blvd STP permit renewal.” E.R. 208. NWEA argues that this statement proves that DEQ had not permitted the CSOs in the 1984 permit. Portland, however, offered an affidavit by the author of the report to explain the statement. Barbara Burton explained that the quoted text did not mean that Portland’s CSOs were not covered by an NPDES permit, and therefore were illegal. Instead, it was intended to convey that “none of the outfalls were individually listed with effluent limitations in Portland’s 1984 NPDES permit.” E.R. 281 (emphasis in original).
Barbara Burton’s impression of the scope of the Portland NPDES permit was shared by Harold L. Sawyer, formerly the Water Quality Division Administrator for DEQ. E.R. 282. Sawyer stated in his affidavit that “Portland’s entire sewer system, including CSO outfalls, was permitted by Portland’s 1984 NPDES permit and by its prior NPDES permits.” E.R. 283. According to Sawyer, DEQ knew, and always had known, that the Portland sewer system operated through a system of CSOs and treatment plants. Id. Moreover, “if DEQ had considered combined sewer overflows to be outside of Portland’s NPDES permit, as Water Quality Division Administrator for DEQ [he] would have proposed a specific program and schedule for treatment or elimination of such discharges for incorporation in the permit or in a separate compliance order.” Id. These are the steps that DEQ took in 1991. Thus, “DEQ understood that Portland would continue to operate its combined sewer system as it had been operating the system prior to the existence of the NPDES permitting program, to prevent dry weather combined sewer overflows except during abnormal storm events.” Id. at 285.
This position is repeated in the 1991 SFO. DEQ stated that “as a matter of policy the Department [DEQ] did not always list CSO discharge points in an NPDES permit but, in many instances, issued permits for an entire sewer system ... [Portland’s] 1984 NPDES permit is a permit for the sewer system, which includes CSO outfalls, but did not contain specific effluent limitations for CSOs.” E.R. 260-61.
The district court, having reviewed these conflicting statements, found Portland’s interpretation to be persuasive. The court recognized the import of the Gaffi letter, but determined that it was “not persuasive enough in the face of the common sense reading of the permit, which when examined in context with the older permits and when construed to give the language limiting discharges meaning, directs a conclusion that the 1984 permit covered the CSO discharges.” E.R. 83. The Sawyer and Burton affidavits were more persuasive because their explanations of the 1984 permit comported with the language of the permit itself. Id.
NWEA argues that, notwithstanding the extrinsic evidence, under the rules of contract interpretation the court must find that the CSOs were not covered by the 1984 permit. Courts should, if possible, interpret a contract so that its terms will not be illegal. See Corbin, Contracts § 546 at 169 (1960). This rule is advisory and should not be applied blindly to the detriment of the parties’ intentions. “[A] specific provision in an otherwise valid contract should not be given a meaning that would have a legal effect that the court is convinced the parties did not [985]*985intend, even though any alternative meaning will cause the provision to have no legal effect whatever.” Id.
Under the regulations promulgated pursuant to § 1342 of the Clean Water Act, all NPDES permits should establish technology-based effluent limitations for all permitted point sources. 40 C.F.R. § 122.44(a). Although technically the permit should have established effluent limitations for the CSOs, it appears that the parties intended to omit such requirements. The district court was presented with sufficient evidence from which it could determine that DEQ, as well as Portland, intended this allegedly unlawful interpretation. EPA approved the terms of the permit, including the absence of effluent limitations for the CSOs, even though the existence of the CSOs was clear on the permit’s face. Moreover, prior to 1989, it appears that many state permitting bodies believed that CSO outfalls could be permitted without being subjected to effluent limitations. See National Combined Sewer Overflow Control Strategy, 54 Fed.Reg. 37370, 37371 (1989) (proposed regulations to “control effluents from combined systems which are not regulated under the sanitary system standards nor as discharges from separate storm sewer regulations”). Cf., Montgomery Environmental Coalition v. Costle, 207 U.S.App.D.C. 233, 646 F.2d 568, 592 (D.C.Cir.1980) (interpreting permit as allowing limited CSO events without effluent limitations).
NWEA next argues that the district court erred by failing to interpret the permit in the public interest. This is “a rule of construction rather than one of interpretation, one that for reasons of public policy requires the court to give to a contract that legal operation that is of public advantage, when a choice between that and a less advantageous operation is reasonably open.” Corbin, supra § 550 at 196. In NWEA’s view, the 1984 permit should be interpreted as not allowing the CSOs because “clearly it is not in the public interest to construe a permit so as to authorize the gross pollution of public waterways.” Reply at 7. The alternative to the CSOs is a total revamping of the Portland sewer system, the cost of which has been estimated at as much as 1.2 billion dollars. E.R. 221. Moreover, until such renovations could be completed, if the excess effluent during storms was not released through the CSOs the effluent would “flood[ ] streets and basements.” Sunnarborg Aff., Supp.E.R. 21. Although water pollution is unfortunate, it beggars credulity to argue that this alternative is so clearly more in the public interest than the CSO events.
The district court’s findings are not clearly erroneous. There was significant evidence from DEQ, the permit author, to indicate that the CSOs were covered in the 1984 permit. Moreover, DEQ’s interpretation, that the CSOs were permitted but not separately listed, does not directly conflict with NWEA’s offered extrinsic evidence. Given Sawyer’s and Burton’s explanations, Gaffi and MacPherson’s concerns about permitting the CSOs can be explained as concern over whether the CSOs should be expressly listed on new permits. We, accordingly, affirm the district court’s finding that the permit authorized limited discharges from the CSOs.
B. Does NWEA Have a Cause of Action for Water Quality Violations?
NWEA argues that the district court erred in finding that it did not have jurisdiction over a citizen suit for the enforcement of the water quality maintenance provision of the NPDES permit.
In the court below NWEA argued that, whether or not the CSOs were specifically permitted under the 1984 NPDES permit, Portland had violated and continued to violate conditions of both the 1984 and 1991 NPDES permits. Specifically, NWEA alleged that Portland’s CSO events violated a permit condition prohibiting any discharges that would violate Oregon water quality standards. The 1984 permit held, as a condition in Schedule A, that “notwithstanding the effluent limitations established by this permit, no wastes shall be discharged and no activities shall be conducted which will violate Water Quality Standards as adopted in OAR 340-41-445 except in the following defined mixing zone ...” 1984 Permit, E.R. 223. The mixing zone was defined as a 100 foot radius around the discharge point. Id. The [986]*9861991 permit contained similar limitations but eliminated the mixing zone provision. It also expressly applied the condition to the CSOs. See E.R. 235 and compare with E.R. 223. NWEA offered declarations and scientific reports that it argued establish continuing violations of the water quality standards in the waters surrounding the CSOs after CSO events. See, e.g., Portland’s Response to Interrogatories, E.R. 119 (failure to meet fecal coliform standards); Thutt Aff., E.R. 164 (“not possible to have any CSO event that would not exceed the DEQ’s fecal coliform standard”); Rosolie Aff., E.R. 153-54.
The district court never reached the question of Portland’s liability for violations of this permit condition. Instead, the district court held that § 505 of the Clean Water Act, 33 U.S.C. § 1365, did not grant federal jurisdiction for the citizen enforcement of water quality violations, “because water quality standards do not equal ‘effluent standards or limitations under this chapter.’” E.R. 84. The court concluded that violations of water quality standards may be actionable “only if they are incorporated into an NPDES permit through effluent limitations.” E.R. 86. Because the plain language of CWA § 505, the legislative history, and case law support a finding of citizen suit jurisdiction in this case, we reverse on this issue.
The plain language of CWA § 505 authorizes citizens to enforce all permit conditions. That section provides: “[A]ny citizen may commence a civil action ... (1) against any person ... who is alleged to be in violation of (A) an effluent standard or limitation under [the Clean Water Act].... ” 33 U.S.C. § 1365(a)(1)(A). An effluent standard or limitation includes “(2) an effluent limitation or other limitation under section 1311 ... or (6) a permit or condition thereof....” 33 U.S.C. § 1365(f)(2), (f)(6) (emphasis added). This language clearly contemplates citizen suits to enforce “a permit or condition thereof.” Portland holds a National Pollutant Discharge Elimination System (NPDES) permit,7 and the water quality standards are conditions of its permit.
Portland argues that § 505 allows citizens to enforce only those water quality standards that are translated into effluent limitations. To support this argument, Portland reasons that the effluent limitations, which were imposed by the 1972 amendments to the CWA, effectively displaced water quality standards as the primary means of regulating pollution. Portland explains that Congress retained water quality standards as the ultimate goal of pollution control, but sought to achieve this goal through end-of-the-pipe limitations.
Portland misconstrues the effect of the legislative history of the 1972 amendments to the CWA. To be sure, the 1972 CWA amendments reflect Congress’ dissatisfaction with the system of water quality standards. But nowhere does Congress evidence an intent to preclude the enforcement of water quality standards that have not been translated into effluent discharge limitations. The fact that Congress created a new, simpler enforcement method based on effluent limitations does not mean that Congress intended to foreclose citizen suit enforcement of water quality standards. In fact, the legislative history indicates just the opposite.
By introducing effluent limitations into the CWA scheme, Congress intended to improve enforcement, not to supplant the old system. In the legislative history, the Senate Committee first outlined the dual purposes of water quality standards: “The standards are intended to function ... [a]s a measure of performance ... [and] to provide an avenue of legal action against polluters. If the wastes discharged by polluters reduce water quality below the standards, actions may be begun against the polluters.” S.Rep. No. 414, 92nd Cong., 2nd Sess. 2 (1972), reprinted in 1972 U.S.C.C.A.N. 3668, 3671; 40 C.F.R. § 131.2 (1992) (dual purposes).
Next, the Committee expressed dismay over the “almost total lack of enforcement” under the old system that depended exclusively upon water quality standards. 1972 U.S.C.C.A.N. at 3672 (“[0]nly one case has reached the courts in more than two dec[987]*987ades.”). Given Congress’ concern about non-enforcement, Portland erroneously takes a narrow view of Congress’ broad provision for “citizen participation in the enforcement of control requirements and regulations established under [the CWA]_” Id. at 3745.
The Senate Committee expressly stated that “fi]n addition to violations of section 301(a) [33 U.S.C. § 1311, Effluent Limitations] citizens are granted authority to bring enforcement actions for violations of .any condition of any permit issued under section 402 [33 U.S.C. § 1342].” 1972 U.S.C.C.A.N. at 3747 (emphasis added).8 Also, the Committee explained that it modeled the citizen suit provision on the analogous Clean Air Act (“CAA”) provision that applies to air pollution permit conditions.9 Id. at 3745. Thus, consistent with the statutory language, the legislative history of the citizen suit provision reflects Congress’ intention to grant broad authority for citizen enforcement.
Ample case law supports our view that Congress intended to confer citizens standing to enforce water quality standards. Most notably, in PUD No. 1 of Jefferson County v. Washington Department of Ecology, — U.S. -, -, 114 S.Ct. 1900, 1910-14, 128 L.Ed.2d 716 (1994) (Jefferson County), the Supreme Court held that the Clean Water Act allows States to enforce the broad narrative criteria contained in water quality standards. In Jefferson County, a county which proposed to build an electricity-generating facility on a river challenged a minimum stream flow condition established by the State.10 Although the county did not contest the State’s authority to set limitations designed to ensure compliance with state water quality standards adopted under CWA § 303, the county argued that § 303 requires the State to protect water quality standards solely through implementation of “specific numerical criteria.” Id. at -, 114 S.Ct. at 1910. The county contended that the State may not require it to operate the dam in a manner consistent with a “designated use,” which is a qualitative requirement of the § 303 water quality standards. Id.
The Court rejected the county’s argument, and held that the State may require a permit applicant to comply with the qualitative designated uses requirement. Id. The Court explained that under the literal terms of CWA § 303(c)(2), a water quality standard must “consist of the designated uses of the navigable waters involved and the water quality criteria for such waters based upon such uses.” Id. Thus, the Court concluded that a project that does not comply with a [988]*988designated use of the water does not comply with the applicable water quality standards. Id. The Court also explained that CWA § 401(d), which provides for State certification of projects, explicitly authorizes “any ... limitations ... necessary to assure that [the applicant] will comply with any ... limitations under ... [CWA § 303] ... and any other appropriate requirement of state law.” Id.
By its holding, the Court expressly rejected the county’s argument that designated use requirements are “too open-ended” to be enforceable and that the Clean Water Act only contemplates enforcement of the more “specific and objective” numerical criteria:
[The county’s] argument is belied by the open-ended nature of the criteria themselves ... criteria are often expressed in broad, narrative terms.... In fact, under the Clean Water Act, only one class of criteria, those governing “toxic pollutants listed pursuant to section 1317(a)(1)” need be rendered in numerical form.... [The county’s] attempt to distinguish between uses and criteria loses much of its force in light of the fact that the Act 'permits enforcement of broad, narrative criteria based on, for example, “aesthetics.”
Id. at -, 114 S.Ct. at 1911 (emphasis added).
The county’s losing argument in Jefferson County is very similar to the argument advanced by Portland in the instant case. Portland argues that citizens may not enforce the broad narrative conditions of state water quality standards, but may enforce only those conditions that have been translated into numeric effluent limitations.
We disagree with Portland’s contention that Jefferson County is inapposite to the issue before us. Even though Jefferson County involved a state’s authority to impose conditions under CWA § 401, whereas the present litigation involves citizen suit enforcement of CWA § 402 conditions, both the § 401 certification process and the § 402 permit process require applicants to comply with CWA § 301. As noted above, § 301 incorporates by reference the water quality requirements of § 303.
Moreover, although Jefferson County addressed the authority of States, not citizens, to enforce the narrative conditions of CWA § 303 water quality standards, nothing in the language of the Clean Water Act, the legislative history, or the implementing regulations restricts citizens from enforcing the same conditions of a certificate or permit that a State may enforce. To the contrary, as demonstrated above, these sources uniformly support broad citizen enforcement authority, including the authority to enforce water quality standards.
In addition to Jefferson County, numerous cases support a finding of citizen suit jurisdiction in this case. The Supreme Court has acknowledged citizen standing under CWA § 505(a)(1) and (f)(6), to enforce permit conditions based on both EPA-promulgated effluent limitations and state-established standards. See E.P.A. v. California, 426 U.S. 200, 224-25, 96 S.Ct. 2022, 2033-34, 48 L.Ed.2d 578 (1976). By applying § 505(f)(6), several courts have held that citizens groups may seek to enforce many kinds of permit conditions besides effluent limitations. In fact, permit conditions that courts commonly enforce under § 505(a) are not effluent limitations, but rather, requirements for retaining records of discharge sampling and for filing reports. See, e.g., Sierra Club v. Simkins Industries, Inc., 847 F.2d 1109, 1115 (4th Cir.1988) (“Simkins’ reporting requirements are expressly made conditions of its permit, and therefore violations of these conditions, by operation of § 1365(f)(6) [CWA § 505(f)(6)], are violations of an effluent standard or limitation of § 1365(a).”), cert. denied, 491 U.S. 904, 109 S.Ct. 3185, 105 L.Ed.2d 694 (1989). Other examples of enforceable permit conditions include conditions relating to sewage maintenance, Pymatuning Water Shed Citizens for a Hygienic Env’t v. Eaton, 506 F.Supp. 902 (W.D.Pa.1980), aff'd, 644 F.2d 995 (3rd Cir.1981), and construction schedules, Locust Lane v. Swatara Township Auth., 636 F.Supp. 534, 539 (M.D.Pa.1986) (rejecting defendant’s attempt “to impose a limitation on § 1365 where one is neither supported by the language nor the legislative history”). Finally, citizens groups may enforce even valid permit conditions that regulate discharges outside the scope of the [989]*989Clean Water Act, namely discharges that may never reach navigable waters. Connecticut Fund For Env’t v. Raymark Indus., Inc., 631 F.Supp. 1283, 1285 (D.Conn.1986).11
Citizen suits to enforce water quality standards effectuate complementary provisions of the CWA and the underlying purpose of the statute as a whole. Citizen suit enforcement of water quality standards is necessary to the effective enforcement of effluent limitations. Congress recognized that water quality standards “often cannot be translated into effluent limitations_” 1972 U.S.C.C.A.N. at 3675. For example, certain water quality standards cannot be expressed quantitatively, such as those that apply in this ease to bacterial pollution, aesthetic conditions, and objectionable matter (scum, oily sleek, foul odors, and floating solids). See Or.Admin.R. 34(Ml-445(2)(f), (l), (k). Even after the 1972 amendments, states may adopt similar standards and express water quality criteria “as constituent concentrations, levels, or narrative statements_” 40 C.F.R. § 131.3(b) (1992).
Many discharges remain unregulated and primarily subject to water quality standards, despite statutory deadlines for achieving effluent limitations, 33 U.S.C. § 1311(b)(1)(A) (1977 deadline for first-stage effluent limitations on all point source discharges), § 1311(b)(2) (West 1993 Supp.) (1989 deadline for second-stage, more stringent controls). Furthermore, in cases where effluent limitations do apply, they serve only as national, minimum requirements; states may adopt stricter, enforceable water quality standards and limitations. 33 U.S.C. § 1370.
By interpreting § 505 to exclude citizen suit enforcement of water quality standards that are not translated into quantitative limitations, Portland would have us immunize the entire body of qualitative regulations from an important enforcement tool.12 Such a result would be especially troubling in this case, because no effluent limitations cover the discharges from Portland’s combined sewer overflows (“CSOs”).13
CSOs are the overflow points from combined sewage and stormwater collection systems. Because the number and volume of overflow events from CSO systems are caused primarily by uncontrollable events— i.e., the amount of stormwater entering the system — regulators have no ready way of determining what portion of the flow in a given discharge event is sewage and what portion is rainwater. Without this information, it is impossible to determine the level at which to set a numeric concentration-based permit limit in order to ensure that the gross amount of pollution discharged will not violate water quality standards.
In Jefferson County, the Supreme Court recognized that the numerical criteria components of state water quality standards cannot reasonably be expected to address all the water quality issues arising from every activity which can affect the State’s hundreds’ of individual water bodies. — U.S. at -, 114 S.Ct. at 1912. The Court reasoned that requiring the States to enforce only the nu[990]*990merical criteria component of their water quality standards “would in essence require the States to study to a level of great specificity each individual surface water to ensure that the criteria applicable to that water are sufficiently detailed and individualized to fully protect the water’s designated uses.” Id. Accordingly, the Court stated that in the absence of “textual support for imposing this requirement,” it was “loath to attribute to Congress an intent to impose this heavy regulatory burden on the States.” Id.
Because the statutory language, legislative history, and ease law authorize citizens to enforce permit conditions stated in terms of water quality standards, we hold that NWEA has standing to enforce the water quality standards contained in Portland’s NPDES permit.
C. Procedural Determinations
In the court below, Portland asserted two other jurisdictional arguments upon which NWEA now seeks a determination. Portland argued that 1) the case was moot because of the changes in the 1991 permit; and 2) any action was barred under 33 U.S.C. § 1319(g)(6) by DEQ’s subsequent enforcement actions.
Because NWEA claims entitlement to attorney’s fees based on the alleged violations of the old permit, and seeks to enforce the water quality standards independently of the effluent limitations, a live and genuine controversy remains, so the ease is not moot. With respect to the § 1319(g)(6) defense, the district court did not reach this question, having ruled against NWEA on other grounds. We therefore remand for a determination on this issue.
III. CONCLUSION
For the foregoing reasons, we AFFIRM the district court’s holding that the 1984 permit covered the CSOs, and we REVERSE the district court’s holding that CWA § 505(a) does not confer jurisdiction for citizen suits to enforce water quality standards when they are conditions of a CWA permit.
AFFIRMED in part, REVERSED in part, and REMANDED.