Brachtenbach, J.
Plaintiffs are three companies which developed residential subdivisions within the city of Bothell (City). As a condition of the preliminary plat approval, the City required execution of "voluntary” agreements under which the developers were required to pay a predetermined $400 per lot as park-impact mitigation fees.
Plaintiffs paid a combined total of $106,000 in such impact fees in 1986 and 1987. Plaintiffs sued for a refund of those fees in 1989. Bothell argued that the suit was time barred by a 30-day limitation in the platting statute, RCW 58.17.180, and that the developers should be estopped from their refund claims.
[242]*242The trial court held that the suit was timely because Both-ell had not complied with RCW 82.02.020, the statute which authorizes impact fees, and, therefore, the 3-year statute of limitations, applicable to actions for the refund of taxes, fees or indirect charges on development, was the governing limitation. The trial court ordered a refund of the fees and prejudgment interest.
The Court of Appeals reversed with Judge Agid dissenting. Henderson Homes, Inc. v. Bothell, 67 Wn. App. 196, 834 P.2d 1071 (1992). The majority held that the claims for refunds were barred by estoppel and by the 30-day limitation of RCW 58.17.180. We reverse the Court of Appeals and affirm the trial court.
The key focus is on RCW 82.02.020 as it existed at relevant times. The City collected these impact fees, as a condition of plat approval, relying solely on RCW 82.02.020. That statute begins with an absolute prohibition against these impact fees: "[N]o county, city, town, or other municipal corporation shall impose any tax, fee, or charge, either direct or indirect ... on the development, subdivision, classification, or reclassification of land.”
There are two narrowly drawn exceptions to this absolute prohibition: (1) "However, this section does not preclude dedication of land or easements [pursuant to RCW 58.17.110, the platting statute]” under certain conditions. RCW 82.02.020. Bothell concedes and the trial court found that Bothell never sought dedication of land to mitigate impacts so this exception is irrelevant.
The second exception is the sole authority for the fees extracted in this case. It provides: "This section does not prohibit voluntary agreements with . . . cities . . . that allow a payment ... to mitigate a direct impact that has been identified as a consequence of a proposed development, subdivision, or plat.” (Italics ours.) RCW 82.02.020. Since it is only this statute which authorized these fees, it must be examined in detail, along with the findings of fact.
[243]*243The Requirements of The Statute and The Findings of The Trial Court
The Statute
(1) Must be voluntary agreement
(2) To mitigate a direct impact that has been identified.
(3) Funds may be expended only for capital improvements, agreed upon by the parties to mitigate the identified direct impact.
Findings of Fact
(1) "The fee agreements were not executed voluntarily.”
(1) "Bothell failed to identify any direct impacts of plaintiffs’ developments on the Bothell park system.” No error assigned to this finding.
(2) ". . . There are no documents or records supporting any analysis by the City of Bothell of the direct impacts of plaintiffs’ developments on the park system.” No error assigned to this finding.
(1) "No capital improvements were ever identified by Bothell or agreed to by plaintiffs that related to mitigation of any impact of plaintiffs’ developments on the park system. Bothell made no attempt to correlate fund expenditures with any impacts of plaintiffs’ developments.” No effective error assigned to this finding.
The findings of fact and conclusions of law are set out in the appendix. However, the status of the findings must be made clear. Two findings are critical and bear repeating. Finding of fact 12: "Bothell failed to identify any direct impacts of plaintiffs’ developments on the Bothell park system.” Clerk’s Papers, at 83. No error is assigned to this finding. Finding of fact 13: "Beyond the conclusionary statements contained in the plat approval conditions for plaintiffs’ development, there are no documents or records supporting any analysis by the City of Bothell of the direct impacts of plaintiffs’ developments on the park system.” [244]*244(Italics ours.) Clerk’s Papers, at 83. No error is assigned to this finding. We must compare those unchallenged findings to the requirement of the statute which must be met to extract an impact fee: "[TJo mitigate a direct impact that has been identified as a consequence of a proposed development, subdivision, or plat.” RCW 82.02.020.
We will summarize or paraphrase other findings of fact which demonstrate clearly that there was a total lack of compliance with the statute. Therefore, the impact fees are unauthorized, constitute an illegal tax, fee or charge and result in an unjust enrichment to the City, all of which leads to application of the 3-year statute of limitations.
Bothell does assign error to the findings mentioned hereafter. However, Bothell nowhere argues that the findings are not supported by substantial evidence, it makes no cites to the record to support its assignments, and cites no authorities. Therefore, its assignments of error to the findings are without legal consequence and the findings must be taken as verities. It is elementary that the lack of argument, lack of citation to the record, and lack of any authorities preclude consideration of those assignments. The findings are verities. Cowiche Canyon Conservancy v. Bosley, 118 Wn.2d 801, 809, 828 P.2d 549 (1992); American Legion Post 32 v. Walla Walla, 116 Wn.2d 1, 7, 802 P.2d 784 (1991); Transamerica Ins. Group v. United Pac. Ins. Co., 92 Wn.2d 21, 29, 593 P.2d 156 (1979); Lewis River Golf, Inc. v. O.M. Scott & Sons, 120 Wn.2d 712, 725, 845 P.2d 987 (1993); Bowles v. Department of Retirement Sys., 121 Wn.2d 52, 80, 847 P.2d 440 (1993).
The relevant findings of fact disclose the following:
1. Bothell had no formula nor ascertainable standards so that a determination of the impact of a project on the park system could be made. (Finding of fact 7.)
2. Bothell "failed to consistently and rationally take into account existing park and recreation facilities in determining the impact of plaintiffs’ developments”. (Finding of fact 8.) Clerk’s Papers, at 82.
[245]*2453. Bothell’s own park plan required consideration of school recreation facilities as part of the park inventory, but in assessing the impact of projects, Bothell ignored its own plan and gave no credit to school recreation facilities. (Finding of fact 9.)
4. When plaintiffs developed their subdivisions, there was a surplus of recreation facilities under Bothell’s own standards. (Finding of fact 10.)
5. Bothell did not undertake any understandable analysis to identify the direct impacts of the developments. (Finding of fact 11.)
6. Bothell never requested that plaintiffs dedicate land for park purposes. (Finding of fact 17.)
In addition to extracting fees as condition of plat approval in complete disregard of the very clear requirements of the statute, the City totally ignored the statutory requirements as to spending the impact fees. The specific fees are to be held in a reserve account, and "may only be expended to fund a capital improvement agreed upon by the parties to mitigate the identified, direct impact”. (Italics ours.) RCW 82.02.020(1).
Again, the findings of fact are compelling against Bothell. They were:
1. No capital improvements were ever identified by Bothell or agreed to by plaintiffs (as required by the statute). (Finding of fact 19.)
2. Bothell made no attempt to correlate expenditures of the fees with any impacts (as required by statute). (Finding of fact 18.)
3. Bothell expended part of these fees for other than capital improvements (prohibited by the statute). (Finding of fact 21.)
The position of the City is best summarized by testimony from its own witness that any correlation between fees paid by plaintiffs and expenditures for the impacts of their projects would be purely coincidental. Verbatim Report of Proceedings vol. 4, at 588, 595-604, 607-10.
[246]*246The City repeatedly claims that these agreements were voluntary. An internal city memorandum shows why the-trial court could and did find they were not voluntary. The internal memorandum is from the acting planning administrator for city council information and includes an analysis by the city attorney regarding "voluntary” agreements. It states in part:
There must be emphasis on making sure that the agreement is "voluntary”. Again, a good record during the proceeding is essential. These include:
(a) Staff statements that the developer has volunteered . . ..
(b) Ask the developer during the course of the hearing if he has voluntarily made the offer or if he agrees with the proposed written conditions.
(c) If the developer qualifies the response in any way pursue it until the 'damning admission’ is elicited.
(e) If the impacts are not mitigated through the voluntary agreement and cannot be otherwise mitigated, then deny the proposal.
(Italics ours.) Clerk’s Papers, at 375-76, 362-80.
The testimony of the developers supports the finding that these were not "voluntary” agreements. They were not negotiated as to the impact amount to be paid or how the funds were to be spent. One of the developers was presented the "voluntary” agreement at the hearing on his application. The Bothell planning administrator told him the city council wanted it signed. Even though the "voluntary” agreement had never been discussed, it provided that he had voluntarily agreed to contribute $45,000 for the park mitigation fee. When the applicant asked what would be the consequences if they did not sign the agreement, he was told "it would probably be the eventual disapproval of my project.” Verbatim Report of Proceedings vol. 1, at 33.
We first consider whether this refund suit was timely brought. The Court of Appeals reasoned that RCW 82.02.020 supplements RCW 58.17.020, and therefore, a writ of review must be brought within 30 days. It erred therein. The platting statute, RCW 58.17, is just that, a platting statute. Specifically, it relates, by its very terms, to the subdivision of [247]*247land. RCW 58.17.010. However, the voluntary payment of fees in RCW 82.02.020 is much broader because it includes more than plats or subdivisions. It specifically authorizes such fee agreements for developments in addition to plats or subdivisions. Thus, construction, remodeling and rezoning are all covered by RCW 82.02.020, yet how can those activities be governed by the platting statute which excludes those activities by its own definitions? The basic premise that RCW 82.02.020 supplements RCW 58.17 collapses when RCW 82.02.020 is read in its entirety. It would be an absurd result to hold that only one of the activities described in RCW 82.02.020, platting, is subject to the time limitation of RCW 58.17, but the other half of the statute must have some other unknown statute of limitations.
Further, when the Legislature intended to have the platting statute apply to RCW 82.02.020, it said so. After prohibiting any tax, fee, or charge on subdivisions, among other actions, it specifically referenced RCW 58.17.110 to permit dedication of lands under RCW 58.17. When it came to the fees here imposed, it made no such reference. Again, this cuts out the essence of the analysis for applying RCW 58.17 to RCW 82.02.020.
The inquiry then is what is the nature of these fees which were not imposed according to the only statutory authority for their imposition? RCW 82.02.020 itself provides the answer for it prohibits any tax, fee, or charge, either direct or indirect, on the subdivision of land, unless the fee is imposed pursuant to the voluntary agreement exception described above. R/L Assocs., Inc. v. Seattle, 113 Wn.2d 402, 409, 780 P.2d 838 (1989) is perfectly clear in its holding that we apply RCW 82.02.020 according to its plain and unambiguous terms. R/L Assocs. holds that a charge in violation of RCW 82.02.020 is invalid.
The holdings in R/L Assocs. are consistent with the principles of Hillis Homes, Inc. v. Snohomish Cy., 97 Wn.2d 804, 810-11, 650 P.2d 193 (1982), even though Hillis Homes predated the language of RCW 82.02.020 which applies here. In Hillis Homes, the court held that a preset, per lot [248]*248fee was an unauthorized tax. Here, Bothell also extracted a preset, per lot fee. Because the City made no attempt to comply with the limited authorization of RCW 82.02.020, the fees are exactly those prohibited by that statute.
This court has consistently held that the 3-year statute of limitations, RCW 4.16.080(3), applies to actions to recover invalid taxes. The same principle applies to fees or charges, direct or indirect, on the subdivision of land when they do not comply with RCW 82.02.020. The underlying rationale for applying the 3-year statute is solidly grounded and long established. Such suits "are actions arising out of implied liabilities to repay money unlawfully received”. Adams Cy. v. Ritzville State Bank, 154 Wash. 140, 144, 281 P. 332 (1929). We applied the 3-year statute to a refund claim for an invalid tax as recently as Robinson v. Seattle, 119 Wn.2d 34, 83, 830 P.2d 318, cert. denied, 121 L. Ed. 2d 598 (1992).
If there is any doubt that these fees, under these facts, are an invalid tax, fee, or charge, another provision of RCW 82.02.020 makes clear the legislative intent to proscribe narrowly the imposition of such fees. The statute provides:
No county, city, town, or other municipal corporation shall require any payment as part of such a voluntary agreement which the county, city, town, or other municipal corporation cannot establish is reasonably necessary as a direct result of the proposed development or plat.
(Italics ours.) RCW 82.02.020. As shown above and as found by the trial court, the City of Bothell certainly did not meet the burden placed on it by the quoted part of the statute, but rather failed to meet any of the requirements of the statute.
Next we turn to the holding of the Court of Appeals that Plaintiffs’ claims are barred by estoppel; Application of the doctrine of equitable estoppel requires a showing that the party to be estopped (1) made an admission, statement, or act which was inconsistent with his later claim; (2) that the other party relied thereon; and (3) that the other party would suffer injury if the party to be estopped were allowed to contradict or repudiate his earlier admission, statement, [249]*249or act. PUD 1 v. Walbrook Ins. Co., 115 Wn.2d 339, 347, 797 P.2d 504 (1990); Wendle v. Farrow, 102 Wn.2d 380, 382-83, 686 P.2d 480 (1984). Equitable estoppel is not favored, and the party asserting estoppel must prove each of its elements by clear, cogent, and convincing evidence. Chemical Bank v. WPPSS, 102 Wn.2d 874, 905, 691 P.2d 524 (1984), cert. denied, 471 U.S. 1065, 85 L. Ed. 2d 497, 105 S. Ct. 2140 (1985); Mercer v. State, 48 Wn. App. 496, 500, 739 P.2d 703, review denied, 108 Wn.2d 1037 (1987).
As stated earlier, RCW 82.02.020 prohibits development fees except those derived from voluntary agreements that allow a payment in lieu of a dedication of land or to mitigate a direct impact that has been identified as a consequence of a proposed development, subdivision, or plat. The payment is to be held in a reserve account and may only be expended to fund a capital improvement agreed upon by the parties to mitigate the identified, direct impact.
It is clear from the record that Bothell was spending the developers’ impact fees for general park use rather than to mitigate site-specific impacts as required by RCW 82.02.020. Since nothing in the agreements or in the developers’ actions can be construed to permit these expenditures, Bothell fails to meet its burden of establishing that the developers made an agreement which they later repudiated to the City’s detriment.
The doctrine of estoppel is available to innocent parties only. Mutual of Enumclaw Ins. Co. v. Cox, 110 Wn.2d 643, 650-51, 757 P.2d 499 (1988); Stohr v. Randle, 81 Wn.2d 881, 884-85, 505 P.2d 1281 (1973). From the record we conclude that Bothell does not have the requisite "clean hands” necessary to assert estoppel. Since Bothell has violated RCW 82.02.020, it is not entitled to use estoppel as a bar to the developers’ claim. See Mutual of Enumclaw Ins. Co. v. Cox, supra; Stohr v. Randle, supra.
The Court of Appeals is reversed; the judgment of the trial court is affirmed.
[250]*250APPENDIX
Findings of Fact
1. Plaintiffs all developed residential subdivisions located within the City of Bothell. Henderson Homes, Inc. (Henderson) developed Amber Ridge, a 162-unit subdivision; Conner Development Co. (Conner) developed Morningside, a 77-unit subdivision; and Dujardin Development Co. (Dujardin) developed Camden Highlands II, a 26-unit subdivision.
2. Defendant City of Bothell is a municipal corporation located within King County, Washington.
3. In 1982 the City of Bothell engaged in litigation with H & K Development and Greenview, Inc., over a proposed development called the "Villages”. This prior litigation was limited to issues regarding alteration of the project, design, densities, road improvements, police and fire staffing requirements, and the indemnity covenants that were required by the City of Bothell. The issue of parks mitigation was not litigated.
4. In its conditions of approval for the proposed Villages project, the City of Bothell made no final determination that the developers of that project would be required to pay park fees.
5. Henderson’s Amber Ridge project was substantially and materially different in type, density and size from the predecessor Villages project. The Villages was a proposed 562-unit multifamily planned unit development, consisting of four parts, designated Villages I-IV. Amber Ridge is a 177-unit single family subdivision that encompasses what was formerly Village II, in addition to other property that was never part of the proposed "Villages” development.
6. Plaintiffs or their predecessors in interest all sought approval of their developments from the City of Bothell, and submitted plat applications.
7. Bothell does not have a formula or any ascertainable standards to measure the demand created by a project against the existing supply of park facilities, so that a determination of the impact of a project on the park system can be made.
8. Bothell failed to consistently and rationally take into account existing park and recreation facilities in determining the impact of plaintiffs’ developments on the park system.
9. Bothell’s park plan states that school recreation facilities should. be included as part of the park inventory. However, in assessing the impact of projects, Bothell gave no credit to school recreation facilities in determining the existing supply of park facilities.
10. At the times plaintiffs developed their subdivisions, there existed a surplus of park and recreation facilities in Bothell for both community parks and neighborhood parks (in the relevant neighborhoods) under Bothell’s own standard of 10 acres of developed park land per 1,000 population.
[251]*25111. The City of Bothell did not undertake any understandable analysis to identify the direct impacts of plaintiffs’ developments on the Both-ell park system.
12. Bothell failed to identify any direct impacts of plaintiffs’ developments on the Bothell park system.
13. Beyond the conclusionary statements contained in the plat approval conditions for plaintiffs’ developments, there are no documents or records supporting any analysis by the City of Bothell of the direct impacts of plaintiffs’ developments on the park system.
14. Despite this absence of analysis, plaintiffs were required, as a condition of approval of their preliminary plats, to pay a park fee to the City of Bothell. Henderson paid $29,600 and $36,400 on June 30, 1987, and August 20,1987, respectively, of which $1,200 was refunded on February 22,1989; Conner paid $15,600 and $15,200 on September 18,1986, and May 18, 1987, respectively; and Dujardin paid $10,400 on May 19, 1986. Dujardin paid its fee under protest.
15. Prior to paying the fees, plaintiffs or their predecessors in interest were required by Bothell to execute "voluntary fee agreements”. The fee agreement for Amber Ridge was executed on February 25,1987; the fee agreement for Morningside was executed on December 12,1985; and the fee agreement for Camden Highlands II was executed on June 11, 1984.
16. The fee agreements were not executed voluntarily.
17. Bothell never requested that plaintiffs dedicate land for park purposes.
18. Bothell made no attempt to correlate fund expenditures with any impacts of plaintiffs’ developments, on either a neighborhood or community basis.
19. No capital improvements were ever identified by Bothell or agreed to by plaintiffs that related to mitigation or any impact of plaintiffs’ developments on the park system.
20. Bothell allocated park fees so that they would be spent within 5 years of collection, without regard to mitigating an identified, direct impact of the project for which the fees were assessed.
21. Bothell expended some of the park fees it collected on items other than capital improvements.
22. Plaintiffs filed their complaint against the City of Bothell on May 16, 1989. On March 13, 1989, more than 60 days prior to filing their complaint, plaintiffs filed an administrative claim with the City of Both-ell.
Conclusions of Law
1. The court has jurisdiction over the parties and the subject matter of this action.
2. Plaintiffs’ claims are subject to the 3-year statute of limitations applicable to actions for the refund of taxes, fees or indirect charges on [252]*252development. Because plaintiffs all brought their claims within 3 years of payment of the fees, these claims were timely brought.
3. The doctrine of res judicata does not apply to the Amber Ridge project by reason of the prior litigation over the Villages project. There is insufficient identity of claims and subject matter to warrant application of res judicata to Amber Ridge. Additionally, Bothell failed to plead res judicata in its answer as required by CR 8(c). Bothell is therefore procedurally precluded from raising this defense.
4. RCW 82.02.020, which was in effect at all times relevant to this case, allows municipalities and developers to enter into voluntary fee agreements in lieu of land dedication by the developer, or to mitigate a direct impact that had been identified as a consequence of the proposed development.
5. The park mitigation fees imposed by the City of Bothell on plaintiffs violated RCW 82.02.020. The fees constituted indirect fees on plaintiffs’ developments to supply revenue for the general park system, and were not regulatory in nature.
6. RCW 82.02.020 places the burden on the City of Bothell to identify direct impacts of plaintiffs’ developments on the Bothell park system. Bothell failed to meet this burden.
7. The fees charged plaintiffs by the City of Bothell were not reasonably necessary as a direct result of plaintiffs’ developments.
8. Under the circumstances of this case, the fee agreements were not executed voluntarily.
9. Bothell’s expenditure of park fees violated the requirements of RCW 82.02.020. Specifically, Bothell failed to consult with plaintiffs prior to expending fees collected from them; failed to spend the fees on capital improvements designed to mitigate an identified, direct impact of plaintiffs’ developments; and spent some of the park fees collected on items other than capital improvements.
10. Plaintiffs are entitled to a return of the $106,000 in fees they paid to the City of Bothell, as well as prejudgment interest at the statutory rate from the date the fees were paid. Specifically, Henderson is entitled to $64,800, plus prejudgment interest; Conner is entitled to $30,800, plus prejudgment interest; and Dujardin is entitled to $10,400, plus prejudgment interest.
Andersen, C.J., and Utter, Durham, Smith, and Johnson, JJ., concur.