Wisconsin’s Environmental Decade appeals from an order denying Decade leave to intervene. Because the circuit court did not abuse its discretion, and because no federal or state statute requires citizen participation in state actions to enforce water pollution control laws, we affirm.
The Sewerage Commission of the City of Milwaukee, later joined by the Metropolitan Sewerage Commission of the County of Milwaukee, brought this action against the DNR in July 1976.1 The city commission sought a declaration invalidating a DNR regulation and requirements in two DNR permits issued to the commission in December 1974 pursuant to that regulation. The requirements pertain to the dates by which the city commission’s South Shore plant and Jones Island plant must comply with effluent limits and water treatment standards. The DNR counterclaimed for forfeitures for violations of the permits and for injunctive relief.2
May 25, 1977 the circuit court entered a judgment adopting a lengthy stipulation by the parties. The stipulation affected a part of the counterclaim. It provided for a program of pollution abatement projects and set deadlines for completion of those projects. Part of the stipulation dealt with correction of wet weather bypassing and overflowing in separate sewer areas and required the commissions to coordinate a districtwide sewer system evaluation. Paragraph (B) (4) provides:
The Sewer System Evaluation Survey Report for each participating municipality shall be submitted to the Department by not later than July 1,1980; at a minimum, it *185shall identify a time schedule which assures that all designated corrective work in each participating municipality is completed by not later than July 1,1986.
In April 1980 the commissions moved to amend Paragraph (B) (4) of the stipulation and therefore the judgment. That paragraph, as the commissions proposed to amend it, would establish dates in 1981 by which certain plans would be submitted and adopted. The proposed amendment would not affect the requirement that all corrective work be completed no later than July 1, 1986. No other change or modification to the stipulation was proposed.
July 28, 1980 the Decade moved for the first time since this action was commenced for leave to intervene in the action.3 Attached to the motion is the affidavit of a Decade officer who states that he uses Lake Michigan for swimming and enjoyment, that in his opinion the May 1977 stipulation was inadequate to protect his rights in the waters of the state and further weakening of the stipulation will make worse an already inadequate situation and will injure his rights in those waters, and that his interest in the waters of the state is not adequately represented by the existing parties. The Decade submitted correspondence with the Attorney General regarding Decade’s attempts to obtain information as to proposed changes in the stipulation. The circuit court denied Decade’s motion and Decade brought this appeal.
1. Timeliness
The circuit court held that Decade’s motion was untimely, with no discussion except to note that the motion was filed three years after the judgment was entered.
Section 808.09, Stats., provides in relevant part:
(1) Upon timely■ motion anyone shall be permitted to intervene in an action when the movant claims an inter*186est relating to the property or transaction which is the subject of the action and the movant is so situated that the disposition of the action may as a practical matter impair or impede the movant’s ability to protect that interest, unless the movant’s interest is adequately represented by existing parties.
(2) Upon timely motion anyone may be permitted to intervene in an action when a movant’s claim or defense and the main action have a question of law or fact in common. ... In exercising its discretion the court shall consider whether the intervention will unduly delay or prejudice the adjudication of the rights of the original parties. (Emphasis added.)
Thus, whether intervention is a matter of right or only permissive, the application to intervene must be “timely.” No statutory definition exists of “timely.”
We conclude that timeliness is determined by the circuit court from all the circumstances in its discretion. The burden is on the movant to show circumstances justifying intervention at a late stage of the litigation.
No Wisconsin case allowing intervention after judgment under sec. 803.09, Stats., or its predecessor has been cited to us. Hoppmann v. Reid, 86 Wis. 2d 531, 273 N.W. 2d 298 (1979), and Mercantile Contract Purchase Corp. v. Melnick, 47 Wis. 2d 580, 177 N.W.2d 858 (1970), held it was not an abuse of discretion under sec. 260.205, Stats. 1973, to deny intervention after judgment. In both cases the supreme court found it significant that the proposed intervenors knew about the action affecting their interests, but failed to act until after judgment. Hoppmann, 86 Wis. 2d at 535-36, 273 N.W.2d at 300-01; Mercantile Contract Purchase Corp., 47 Wis. 2d at 591, 177 N.W.2d at 863.
Rule 24 of the Federal Rules of Civil Procedure resembles sec. 803.09, Stats., and does not define timeliness. Under federal case law timeliness is to be determined from all the circumstances by the trial court in the exer*187cise of its sound discretion. NAACP v. New York, 418 U.S. 345, 366 (1973); Federal Dep. Ins. Corp. v. Hanrahan, 612 F.2d 1051, 1053 (7th Cir. 1980).
The federal courts take into account various factors in making a determination of timeliness. Nevilles v. Equal Employment Opportunity Com’n, 511 F.2d 303, 305 (8th Cir 1975) (how far proceedings have gone, prejudice which delay might cause to other parties, and reasons for delay). Accord, Alaniz v. Tillie Lewis Foods, 572 F.2d 657, 659 (9th Cir.), cert. denied, 439 U.S. 837 (1978) ; Commonwealth of Pa. v. Rizzo, 530 F.2d 501, 506 (3d Cir.), cert. denied, 426 U.S. 921 (1976). Stallworth v. Monsanto Co., 558 F.2d 257, 264-65 (5th Cir. 1977) (how long intervenor knew or should have known of an interest in the case, or that its interests were no longer protected by an existing party, before it sought intervention; prejudice to other parties from failure promptly to request intervention; prejudice to intervenor if intervention is denied; and unusual circumstances). Accord, Culbreath v. Dukakis, 630 F.2d 15 (1st Cir 1980). United States v. American Tel. and Tel. Co., 642 F.2d 1285, 1295 (D.C. Cir. 1980) (time since suit was begun, why intervention is sought, need for intervention to preserve the applicant’s rights, and probability of prejudice to existing parties).
Entry of judgment does not automatically make a petition to intervene untimely in the federal courts. Stallworth, 558 F.2d at 266. But post-judgment petitions have generally been looked upon with “a jaundiced eye.” McDonald v. E.J. Lavino Company, 430 F.2d 1065, 1071-72 (5th Cir. 1970). They are unusual and not often granted. 3B Moore’s Federal Practice par. 24.13(1) at 24-526 (1980). Such petitions tend to prejudice the existing parties or interfere with the orderly process of the court. United States v. United States Steel Corp., 548 F.2d 1232, 1235 (5th Cir. 1977); McDonald, 430 F.2d at 1072. These *188factors are not necessarily present where the proposed intervenor after judgment is concerned only with the remedial aspects of the case. Hodgson v. United Mine Workers of America, 473 F.2d 118, 129 (D.C. Cir. 1972), and cases cited. In some courts’ view the most important consideration is whether an existing party will be harmed by the would-be intervenor’s failure to seek intervention sooner. McDonald, 430 F.2d at 1073, and cases cited.
We agree with those courts which require the post-judgment applicant to show sufficient reason for having waited. Nevilles, 511 F.2d at 305. “The general rule is that motions for intervention made after entry of final judgment will be granted only upon a strong showing of entitlement and of justification for failure to request intervention sooner.” United States v. Associated Milk Producers, Inc., 534 F.2d 113, 116 (8th Cir.) (emphasis in original), cert. denied, 429 U.S. 940 (1976). Moore states that post-judgment intervention may be allowed where it is the only way to protect the movant’s rights. 3B Moore’s Federal Practice para. 24.13(1) at 24-527 (1980).
The apparent reasons for the circuit court’s denial of Decade’s petition to intervene were the late stage of the proceeding and the long period of Decade’s inaction. These reasons are sufficient to deny a post-judgment petition for intervention. Hoppmann, supra; Mercantile Contract Purchase Corp., supra.
The circuit court did not discuss the other factors considered by the federal courts for the very good reason that the record is silent as to those factors. Decade cannot complain if the circuit court, when exercising its discretion, failed to consider factors on which Decade presented no evidence.
As the party seeking to intervene at a late stage in the proceeding, the burden is on Decade to show entitlement *189and justification. Associated Milk Producers, 534 F.2d at 116. That burden is increased by the supreme court’s recognition that “the timely resolution of both factual and legal disputes is very important to the progress against environmental pollution which is envisaged by ch. 147.” Sewerage Commission of Milwaukee v. DNR, 102 Wis. 2d 613, 631, 307 N.W.2d 189, 198 (1981). Decade has not met that burden.
The affidavit supporting Decade’s motion does not set forth facts justifying its intervention. Decade’s unexplained dissatisfaction with the judgment as entered hardly justifies its past failure to seek intervention. The record contains no basis for Decade’s assertion that representation of its interests by the DNR is inadequate. Ordinarily a party’s representation is deemed adequate to protect the proposed intervenor’s interest if there is no showing of collusion between the representative and the opposing party; if the representative does not represent an interest adverse to that of the movant; and if the representative does not fail in the fulfillment of its duty. United States v. Board of Sch. Com’rs, Indianapolis, Ind., 466 F.2d 573, 575 (7th Cir. 1972), cert. denied, 410 U.S. 909 (1973).
Collusion between the DNR and the plaintiff commissions has not been shown or even alleged. Decade does not claim that its interests and those of the DNR in protecting the. quality of water have diverged since the judgment was entered. Decade has asserted no interest different from that of all citizens in having clean water. Decade has not shown that the DNR has failed to perform its statutory duties.
Furthermore, Decade has offered no explanation why it believes intervention is necessary at this juncture, when all that the commissions have proposed is a change in the filing dates for some reports. No explanation has been offered as to why Decade sees this as a critical move or change in the stipulation.
*190We conclude that the circuit court did not abuse its discretion when it held that Decade’s petition to intervene was not timely.
A second chance for Decade to justify intervention would be inappropriate. It would add another layer and probably more delay to this suit. It would be inconsistent with the importance of the “timely resolution” of factual and legal disputes in environmental litigation. Sewerage Commission, 102 Wis. 2d at 631, 307 N.W.2d at 198.
Accordingly, we will not order a further hearing on Decade’s motion to intervene.
2. Mandatory Intervention
The circuit court found that no right to intervene in a state enforcement action is conferred by the Federal Water Pollution Control Act (FWPCA), 33 U.S.C. secs. 1251 et seq. Section 1365(b) (1) (B) of the federal law confers on citizens the right to intervene in enforcement actions brought under the FWPCA in federal court, but is silent as to intervention in state court actions.4 Section 147.01(2), Stats., authorizes the DNR to establish a pollutant discharge elimination system to effectuate this state’s policy to abate pollution “consistent with all the requirements of” FWPCA, but contains no provision comparable to that in the FWPCA for citizen participation in state enforcement actions.
Citizens for a Better Environ. v. Environmental Protection Agency, 596 F.2d 720, 723 (7th Cir. 1979), held that Congress intended by the FWPCA that “EPA guidelines *191would address, and state programs following those guidelines would provide for, citizen participation in . . . enforcement” actions. Appellant contends that new federal regulations at 40 C.F.R. sec. 123.9(d) (1980), promulgated after the Citizens decision, require a state plan for citizen participation in the enforcement process.
The EPA regulations require the states to adopt a plan that will satisfy one of two alternatives so as to provide for public participation in the state enforcement process.5 It is not clear whether the federal regulations require post-judgment public participation in the state enforcement process. The circuit court found that Wisconsin authorities are in the process of determining how best to satisfy the federal regulations, and appellant does not challenge that finding. The circuit court cannot enforce a state regulation which has not yet been adopted.
Decade asserts that the new federal regulations must be enforced against the state because the state already has a mechanism for citizen participation in the enforcement process by virtue of its intervention statute, sec. 803.09, Stats. Section 803.09 does not address alterna*192tives for citizen participation under the FWPCA or adopt either of the alternatives set out in the new federal regulations. (See n. 5.) And Decade cannot intervene under sec. 803.09 because it failed to meet the timeliness requirement.
We conclude that the circuit court correctly held that neither federal nor state law requires the granting of Decade’s motion to intervene.
By the Court. — Order affirmed.
See Sewerage Commission of Milwaukee v. DNR, 102 Wis. 2d 613, 307 N.W.2d 189 (1981), for a more complete history of this case.
The supreme court subsequently held in Sewerage Commission, note 1 supra, that the action for declaratory relief was not timely brought and directed the circuit court to dismiss the complaint but not the counterclaim.
An officer of Decade unsuccessfully sought personally to intervene in 1977. The Decade did not.
The federal statute, 33 U.S.C. sec. 1365(b) (1) (B), states:
(b) No action may be commenced—
(1) under subsection (a)(1) of this section—
(B) if the Administrator or State has commenced and is diligently prosecuting a civil or criminal action in a court of the United States, or a State to require compliance with the standard, limitation, or order, but in any such action in a court of the United States any citizen may intervene as a matter of right.
The EPA regulations, 40 C.F.R. sec. 123.9(d) (1980), direct that:
(d) Any State administering a program shall provide for public participation in the State enforcement process by providing either:
(1) Authority which allows intervention as of right in any civil or administrative action to obtain remedies specified in paragraphs (a)(1), (2) or (3) of this section by any citizen having an interest which is or may be adversely affected; or
(2) Assurance that the State agency or enforcement authority will :
(i) Investigate and provide written responses to all citizen complaints submitted pursuant to the procedures specified in § 123.8(b) (4);
(ii) Not oppose intervention by any citizen when permissive intervention may be authorized by statute, rule, or regulation; and
(iii) Publish notice of and provide at least 30 days for public comment on any proposed settlement of a State enforcement action.