TYMKOVICH, Chief Judge.
Sierra Club brought a citizen suit seeking civil penalties against Oklahoma Gas and Electric . Company “(OG & E)” for alleged violations of the Clean Air Act. Sierra Club asserts that in March and April 'of 2008, OG & E, the owner and operator of a coal-fired power plant in Muskogee, modified a boiler at the plant without first obtaining an emission-regulating permit as required under the Act. Because Sierra Club filed its action more than five years after construction began on the plant, the district court dismissed its claim under Rule 12(b)(6) as barred by the statute of limitations. The court also dismissed Sierra Club’s claims for declaratory and injunctive relief because these remedies were predicated on the unavailable claim for civil penalties..
We agree with the district court and conclude that Sierra Club’s claim for civil penalties is statutorily time-barred under 28 U.S.C. § 2462 because it was brought more than five years after the date when the cause of action first accrued. In addition, Sierra Club’s claims for declaratory and injunctive relief are precluded because they are based on the same facts as the time-barred claim for civil penalties.
Accordingly, we AFFIRM.
I. Background
The. Clean Air Act (CAA) directs states to achieve and maintain air quality standards set by the EPA. Each state must adopt a state implementation plan (SIP) for meeting these goals, subject to EPA approval. See 42 U.S.C. §§ 7407(a), 7410(a), 7410(k). In “attainment” areas, where air quality 'is already up "to standards, see id. § 7407(d)(1)(A)(ii), SIPs must comply with the federal Prevention of Significant Deterioration (PSD) program, see id. §§ 7470-7492. The purpose of this program is to protect air quality from significant deterioration caused by new emissions. See id. § 7470. To further that aim, the PSD program provides that a “major emitting facility” cannot be constructed or modified without a permit that sets emission limitations. Id. § 7475(a)(1)1; see also id. § 7479(2)(c) (de[670]*670fining “construction” to include “the modification ... of' any source or facility”). Oklahoma’s SIP, which has been approved by the EPA, honors this requirement by providing that “[n]o person shall cause or allow the construction or modification of any source” without obtaining a PSD permit from the Oklahoma Department of Environmental Quality. Oklahoma SIP Regulations § 1.4.2(a)(1);2 see a¿so id. § 1.4.4 (setting specific requirements that major emission sources must meet to receive a permit).
■According to the complaint, OG & E began modifying a boiler at its Muskogee power plant sometime in March 2008. The plant is a major emitting facility located in an attainment area and therefore was subject to the PSD permit requirement. OG & E did not obtain a PSD permit before commencing the project. Nor did the company secure one before the modification ended sometime in April 2008. Sierra Club alleges that the modification resulted in an increase in the emission of pollutants.
.Although the modification was completed in April 2008, Sierra Club took no legal action until 2013. At that time, it notified OG & E that it intended to bring suit under the CAA, which grants any person a cause of action against an entity that constructs or modifies a major emitting facility without a PSD permit. See 42 U.S.C. § 7604(a)(3). Sierra Club sought civil penalties under 42 U.S.C. § 7413(e)(2) for each day of unpermitted modification activity, as well as declaratory relief and an injunction requiring OG & E to obtain a PSD permit and upgrade its pollution controls so as to comply with Oklahoma regulations. The parties subsequently entered an agreement that tolled the statute of limitations effective April 1,2013.
Because the CAA does not specify a statute of limitations for bringing a citizen suit for civil penalties, the default five-year statute of limitations for civil penalties, fines, and forfeitures under federal law applies. See 28 U.S.C. § 2462. Thus, the parties agreed that any penalties originating before April 1, 2008—five years pri- or to the tolling agreement—were time-barred. The question was whether Sierra Club, could maintain a claim for penalties originating on April 1,2008 or later.
The district court dismissed Sierra Club’s claim for civil penalties, holding any failure on OG & E’s part to obtain a PSD permit would have- been a violation that accrued at the commencement of modification of the boiler, which was before April 1, 2008. The court also, dismissed Sierra Club’s equitable claims for injunctive and declaratory relief because they were predicated on the time-barred legal claim.3
[671]*671II. Analysis
Sierra Club makes two arguments. First, it contends that the statute of limitations does not bar its claim for civil penalties because OG & E continued to violate the CAA until it completed the modification, which was sometime after April 1, 2008. Second, it asserts that its claims for equitable relief are not expired because they are separate from’its claim for civil penalties; Sierra Club seeks equitable relief as an alternative remedy, rather than as a means to enforce its civil penalties claim.
We consider these arguments in turn, first holding the statute of limitations bars Sierra Club’s suit for civil penalties because the claim first accrued when modification commenced. We next hold Sierra Club’s actions for injunctive and declaratory relief are precluded by the concurrent remedy doctrine.4
A. Statute of Limitations
We review de novo “a district court’s ruling regarding the applicability of a statute of limitations.” Plaza Speedway, Inc. v. United States, 311 F.3d 1262, 1266 (10th Cir.2002) (internal quotation mark omitted). A statute of limitations defense “may be appropriately resolved on a [Rule] 12(b) motion when the dates given in the complaint make clear that the right sued upon has been extinguished.” Lee v. Rocky Mountain UFCW Unions & Emp’rs Tr. Pension Plan, 13 F.3d 405, at *1 (10th Cir.1993) (Table).
An action seeking civil penalties for failure to obtain a PSD permit must be brought “within five years from the date when the claim first accrued.” 28 U.S.C. § 2462.- The parties agree that a PSD permit is a pre-construction or pre-modifi-cation requirement, but disagree as to whether the beginning of the -limitations period is delayed as long as the unpermit-ted construction or modification process continues. Sierra Club argues that the statute of limitations resets on each day of unpermitted construction or modification, which in this case included days after April 1,2008.
Sierra Club raises two distinct theories: (1) OG & E committed , a new, discrete violation on each day of unpermitted modification, which we refer to as a theory of “repeated violations”; or (2) OG & E committed a single violation when it began unpermitted construction, but that violation continued until construction was completed. We refer to the latter as a theory of “continuing violation.” In Sierra Club’s view, if either of these theories is correct, then the statute of limitations does not preclude civil penalties for days of modification beginning with April 1, 2008. In contrast, OG & E maintains that the failure to procure a PSD permit generated a single claim for one day’s penalty that accrued only on the first day of modification, which of course occurred before April 1,2008.
We need not consider whether OG & E’s position is correct because we conclude that Sierra Club’s claim for penalties is time-barred for other reasons. The statute of limitations begins to run as soon as a claim “first aecrue[s].” (emphasis added). Id. As explained below, if any form of violation exists beyond the first day of unpermitted modification, it is best characterized as a continuing violation rather than a series of repeated violations.5 [672]*672And because this particular violation first accrued when modification commenced, the statute under § 2462 began to run on that date. That was more than five years before Sierra Club brought suit, and any penalties are accordingly time-barred.
A single violation continues over ah extended period of time “when the plaintiffs claim seek's, redress for injuries resulting from a series of separate acts that collectively constitute one unlawful act,” as opposed to “conduct that is a discrete unlawful act.” Shomo v. City of New York, 579 F.3d 176, 181 (2d Cir.2009) (internal quotation marks omitted) (quoting Nat’l R.R. Passenger Corp. v. Morgan, 536 U.S. 101, 117, 122 S.Ct. 2061, 153 L.Ed.2d 106 (2002)). In other words, one violation continues when “the conduct as a whole can be considered as a single course of conduct.” Birkelbach v. SEC, 751 F.3d 472, 479 n. 7 (7th Cir.2014). The violation must involve some affirmative conduct within the limitations period and “not merely the abatable but unabated inertial consequences of some pre-limitations action.” Poster Exch., Inc. v. Nat’l Screen Serv. Corp., 517 F.2d 117, 128 (5th Cir. 1975).
That is the situation when an emissions facility is constructed or modified without a permit, as constructing or modifying a facility is best characterized as a single, ongoing act. To repeat, the CAA prohibits . unpermitted construction or modification of a “major emitting facility.” 42 U.S.C. § 7475(a)(1). It is the act of constructing itself that is unlawful, see Sierra Club, Inc. v. Sandy Creek Energy Assocs., 627 F.3d 134, 141 (5th Cir.2010) (holding a related CAA preconstruction requirement “simply renders the act of constructing itself unlawful”). “Construct” is an “active verb [] that ha[s] force after ., construction ... has begun.” Wildearth Guardians v. Lamar Utils. Bd., Civil Action No. 1:09-CV-02974-DME-BNB, 2010 WL 3239242, at *5 (D.Colo. Aug. 13, 2010). Thus, “construct” should not be read to encompass a disjointed series of discrete acts of construction. To “construct” is an ongoing project. Accordingly, if we. accept Sierra Club’s argument that some form of violation exists beyond the first day of modification, it must be characterized as a single, continuing violation.
Sierra Club argues that where a continuing violation exists, the limitations period under §. 2462 does not begin to run until the final day of the violation—here, the final day of unpermitted modification, which was sometime after April 1, 2008. Although we could consider this argument forfeited because it was not raised below, we reject it anyway.6 The specific statute [673]*673of limitations at issue begins to run when a claim “first accrue[s].” 28 U.S.C. § 2462 (emphasis added). “[A] claim accrues when the plaintiff has a complete and present cause of action.” Gabelli v. SEC, — U.S. —, 133 S.Ct. 1216, 1220, 185 L.Ed.2d 297 (2013) (internal quotation marks omitted). In other words, a claim accrues as soon as “the plaintiff can file suit- and obtain relief.” Heimeshoff v. Hartford Life & Accident Ins. Co., — U.S. —, 134 S.Ct. 604, 610, 187 L.Ed.2d 529 (2013) (internal quotation marks omitted). And a continuing violation is actionable even before the last act of the violation where the conduct that has already occurred is sufficient to support a claim. See Nat’l R.R. Passenger Corp. v. Morgan, 536 U.S. 101, 117, 122 S.Ct. 2061, 153 L.Ed.2d 106 (2002) (“As long as the employer has engaged in enough activity to make out an actionable hostile environment claim, an unlawful employment practice has ‘occurred,’ even if it is still occurring.”).
In this case, it is clear that Sierra Club could have brought suit for the PSD permit violation on the first day of modification. Even one day of unpermitted modification would have presented a “complete and present” violation of the statute. See 40 C.F.R. § 51.166(a)(7)(iii) (“No new major stationary source or major modification to which the requirements [herein] apply shall begin actual construction without a permit that states that the major stationary source or major modification will meet those requirements.” (emphasis added)); United States v. Midwest Generation, LLC, 720 F.3d 644, 647 (7th Cir.2013) (“The violation is complete when, construction commences without a .permit in hand.”); see also United States v. EME Homer City Generation, L.P., 727 F.3d 274, 285 (3d Cir.2013) (quoting the same). Consequently, Sierra Club’s cause of action first accrued prior to April 1, 2008, even if the violation continued until some later date. Any penalties stemming from the alleged violation are therefore time-barred. ,
Sierra Club asserts that because “[a] penalty may be assessed for each day of violation,” 42 U.S.C. § 7413(e)(2), the claim reaccrues oh each day of a continuing violation. But whether the claim reaccrues does not answer or even-address when it first accrues. We see a difference between the availability of a statutory penalty and the initial accrual of the violation giving rise to penalties.
Next, Sierra Club cites four cases for the claim that a continuing violation extends' the deadline to file suit under § 2462. Three of them are easily distinguished. In the first, Havens Realty Corp. v. Coleman, the Supreme Court held “where a- plaintiff, pursuant to- the Fair Housing Act, challenges hot just one incident of conduct violative of the Act, but an unlawful practice that continues into-the limitations period,” the statutory clock begins upon “the last asserted occurrence of that practice.” 455 U.S. 363, 380-81, 102 S.Ct. 1114, 71 L.Ed.2d 214 (1982). Havens concerned a different , statute, of limitations employing substantially different language: “A civil action shall be commenced within one hundred and eighty days after the alleged discriminatory housing practice occurred.” Id. at 380 n. 22, 102 S.Ct. 1114 (internal quotation marks omitted). That statute .allowed the limitations period to continue as long as the discriminatory practice “occurred.” Id. at 381, 102 S.Ct. 1114. In contrast, the clock under § 2462 [674]*674begins only once, when a claim first accrues. If the limitations period under § 2462 reset each day,, the statutory term “first” would have no operative force. In other words, the statute could just as easily state that the limitations period begins whenever “the claim accrues.”
Second, Sierra Club’s reliance on United States v. Jaynes, 75 F.3d 1493 (10th Cir. 1996), as well as its reliance on our unpublished decision in United Slates v. Shaw, 150 Fed.Appx. 863 (10th Cir.2005) are equally unavailing.- Those cases involved the distinct “continuing offense” doctrine in the criminal context. There, a “continuing offense” “is a term of art” that we generally avoid applying unless “the explicit language of the substantive criminal statute compels such a conclusion, or the nature of the crime involved is such that Congress must assuredly have intended that it be treated as.a continuing one.” Jaynes, 75 F.3d at 1506 (internal quotation marks omitted). More importantly, like Havens-, these cases did not concern the unique “first accrued” language of § 2462.
Lastly, Sierra Club points to a Fifth Circuit administrative appeal for the proposition that the beginning of the limitations period under § 2462 is extended as long as a violation continues. In Newell Recycling Co. v. EPA, the Fifth Circuit upheld an administrative determination that a claim against a recycling facility’s improper disposal of pollutants did not accrue until the facility properly disposed of the contaminated soil. 231 F.3d 204, 206-07 (5th Cir. 2000). As a result, the limitations period under § 2462 did not begin to run until the proper disposal, ie., the end of the violation. Id. at 206. We find this holding unpersuasive. First, the court deferred to the interpretation of the administrative board and-, did not undertake a de novo review of the statute. Second, the board’s reasoning that no claim “accrued” until the violative conduct ended is inconsistent with more recent. Supreme Court cases that hold a claim accrues “when the plaintiff can file suit and obtain relief.” Heimeshoff, 134 S.Ct. at 610 (internal quotation marks omitted); see also Gabelli, 133 S.Ct. at 1220 (“[A] claim accrues when the plaintiff has a complete and present cause of action.” (internal quotation marks omitted)). Finally, the court nowhere addressed the significance of the phrase, “first accrued,” in § 2462. Thus, to the extent that Newell suggests the limitations period under § 2462 does not begin to run as long as an already-ripe violation continues, we disagree.
As a final note, we have observed that “the continuing violation doctrine is premised on the equitable notion that the statute” of limitations should not begin to run until a reasonable person would be aware that his or her rights have been violated.” Davidson v. Am. Online, Inc., 337 F.3d 1179, 1184 (10th Cir.2003) (internal quotation marks omitted). It follows that , “a continuing violation claim fails if the plaintiff knew, or through the exercise of reasonable diligence would have known” of the injury when it began. Id. at 1184 (internal quotation marks omitted). Here, nothing prevented Sierra Club from discovering, within five years, that it had an actionable claim as soon as OG & E began construction.7
In sum, § 2462 requires that a suit be filed within five years of when a claim first accrues, which in this case was when OG & E commenced modification of the boiler. [675]*675Because Sierra Club brought suit more than five years after that date, its claim, is now time-barred.
B. Concurrent Remedy Doctrine
Sierra Club also seeks declaratory relief and an injunction requiring OG & E to obtain a PSD permit and upgrade its pollution controls. But it relies on the same theory that underlies its claim for civil penalties: OG & E unlawfully modified a boiler at the Muskogee plant without a permit.8 Even so, Sierra Club contends that if its suit for civil fines is time-barred, the statute of limitations has no effect on its equitable claims. We disagree because the equitable claims are based on the same facts supporting the time-barred legal claim.
Although § 2462 bars ' Sierra Club’s suit for civil penalties, its language does not, in and of itself, limit actions for equitable relief. See United States v. Telluride Co., 146 F.3d 1241, 1245 (10th Cir. 1998). Nonetheless, the concurrent remedy doctrine provides that a statute barring a legal claim will also bar an equitable claim “when the jurisdiction of the federal court is concurrent with that at law, or the suit is brought in aid of a legal right.” Russell v. Todd, 309 U.S. 280, 289, 60 S.Ct. 527, 84 L.Ed. 754 (1940). This rule applies whenever “an action at law or equity could be brought on the same facts.” Telluride, 146 F.3d at 1248 n. 12.
Relying on Russell, 309 U.S. at 289, 60 S.Ct. 527, Sierra Club contends that-an equitable action is only brought “in aid of’ a legal right when it would be necessary to effectuate a legal remedy. In Russell, a bank’s shareholders were individually responsible for the bank’s debts. Id. When the bank’s creditors sued the shareholders, the district court needed to determine the extent of liability for each shareholder. To do that, the court first had to exercise its equity jurisdiction to perform an assessment that would uncover the relevant facts. Id. at 285-86, 60 S.Ct. 527. The Supreme Court held the primary action was itself an action in equity, id. at 286-87, 60 S.Ct. 527, and therefore that a legal statute of limitations did not apply, id at 289, 60 S.Ct. 527. The Court explained, however, that where the primary claim is a legal claim barred by a legal statute of limitations, the exercise of equity jurisdiction to determine the underlying facts would also be barred. Id. Sierra Club argues that this case only holds an.equitable claim is barred where it is a mere prerequisite to resolving a legal dispute, In. Sierra Clubs view, a stand-alone request for equitable relief can therefore survive even where a legal remedy based on the same facts is expired.
We disagree. Sierra Club’s narrow reading of Russell contradicts our observation that an equitable claim is unavailable when it can be , brought on the same facts as an expired legal claim. Telluride, 146 F.3d at 1248 n. 12. It follows from this rule that an, equitable claim is barred where “the only difference between” it and a time-barred legal claim “is the relief sought.” Grynberg v. Total S.A., 538 F.3d 1336, 1353 (10th Cir.2008). Otherwise, a legislative determination that a particular time .limit is sufficient to take action against wrongful conduct “could be undermined by permitting less timely claims for such [conduct] when only equitable remedies are sought.” Id.
Relying on the .same principles, the Eighth and Eleventh Circuits have [676]*676similarly held that where a statute of limitations precludes civil penalties for failing to obtain a PSD permit, equitable remedies based on the same facts are barred as well. See Sierra Club v. Otter Tail Power Co., 615 F.3d 1008, 1018-19 (8th Cir.2010); Nat’l Parks & Conservation Ass’n v. Tenn. Valley Auth., 502 F.3d 1316, 1327 (11th Cir.2007). We agree and hold Sierra Club cannot win injunctive or declaratory relief for OG & E’s alleged PSD permit violation because its legal remedy based on the same facts is time-barred.9
Finally, Sierra Club asserts that the concurrent remedy doctrine is inapplicable because it is acting as a “private attorney general” in place of the government. A suit brought by the government in its sovereign capacity “is not subject to "a time limitation unless Congress explicitly imposes one and any statute of limitations sought to be applied against the United States must receive a strict construction in favor of the Government.” Telluride, 146 F.3d at 1248 (internal quotation marks omitted). Accordingly, the concurrent remedy doctrine does not apply to the government. Id. at 1249. But Sierra Club is not the government, regardless of how it views its own role. A citizen suit under the CAA is brought on the plaintiffs “own behalf.” 42 U.S.C. § 7604(a). Private plaintiffs cannot be said to “represent the public at large in the same way the government does when it brings suit to enforce the statute,” Nat’l Parks, 502 F.3d at 1327, and thus are not eligible for the government’s exemption.
III. Conclusion
For the foregoing reasons, we AFFIRM the district court’s Rule 12(b)(6) dismissal of Sierra Club’s claims.