Wis. Stat. § 62.11
When a municipality's power to contract is improperly or irregularly exercised and the municipality receives benefit under the contract, it is estopped from asserting the invalidity of the contract. Village of McFarland v. Town of Dunn, 82 Wis. 2d 469, 263 N.W.2d 167 (1978). Madison's power to forbid chemical treatment of Madison lakes was withdrawn by s. 144.025(2) (i) [now s. 281.17(2)]. Wisconsin Environmental Decade, Inc. v. DNR, 85 Wis. 2d 518, 271 N.W.2d 69 (1978). When a city council creates a governing board for a utility under s. 66.068(1) [now s. 66.0805(1)], the council is prohibited by s. 66.068(3) [now s. 66.0805(3)] from fixing wages for utility employees. Schroeder v. City of Clintonville, 90 Wis. 2d 457, 280 N.W.2d 166 (1979). Sub. (5) authorizes an ordinance regulating massage parlors. City of Madison v. Schultz, 98 Wis. 2d 188, 295 N.W.2d 798 (Ct. App. 1980). There is a four-part test in evaluating whether a municipality may regulate a matter of state-wide concern: 1) whether the legislature has expressly withdrawn the power of municipalities to act; 2) whether the ordinance logically conflicts with the state legislation; 3) whether the ordinance defeats the purpose of the state legislation; or 4) whether the ordinance goes against the spirit of the state legislation. Anchor Savings and Loan Association v. Madison EOC, 120 Wis. 2d 391, 355 N.W.2d 234 (1984). The common council and mayor properly limited the power of the police and fire commission to promote police officers. State ex rel. Wilson v. Schocker, 142 Wis. 2d 179, 418 N.W.2d 8 (Ct. App. 1987). Liberally construing home rule authority, a city is not authorized to institute a public safety officer program. Local Union No. 487 v. Eau Claire, 147 Wis. 2d 519, 433 N.W.2d 578 (1989). The power granted under sub. (5) is broader than that granted under Art. XI, s. 3. Sub. (5) does not limit a city's authority to act only in local affairs. A city may act in matters of state-wide concern if the conditions of the four-part test stated in this case are met. DeRosso Landfill Co. v. City of Oak Creek, 191 Wis. 2d 46, 528 N.W.2d 468 (Ct. App. 1995). The state regulatory scheme for tobacco sales preempts municipalities from adopting regulations that are not in strict conformity with those of the state. U.S. Oil, Inc. v. City of Fond du Lac, 199 Wis. 2d 333, 544 N.W.2d 589 (Ct. App. 1995), 95-0213. One who deals with a municipality does so at his or her own risk and may be subject to any provisions of law that might prevent him or her from being paid by a municipality even though the services are rendered. Unless the power to bind the municipality financially has been specifically delegated, the only entity with the statutory authority to contract is the municipality. Holzbauer v. Safway Steel Products, Inc., 2005 WI App 240, 288 Wis. 2d 250, 712 N.W.2d 35, 04-2058. When a challenge to the exercise of police powers is directed at the legislative means employed, the issue is properly framed as one of substantive due process. The legislative means chosen must have a rational relationship to the purpose or object of the enactment; if it has, and the object is a proper one, the exercise of the police power is valid. The fundamental inquiry is not whether the challenged provisions in an ordinance are rationally related to the stated purpose of the ordinance but whether the challenged provisions are rationally related to any legitimate municipal objective. Metropolitan Milwaukee Association of Commerce, Inc. v. City of Milwaukee, 2011 WI App 45, 332 Wis. 2d 459, 798 N.W.2d 287, 09-1874. An ordinance is not invalid as unreasonable merely because substantially the same result might be accomplished by the enactment of a different type of ordinance, or because a less burdensome course might have been adopted to accomplish the end. The correct standard is whether the legislative means chosen has a rational relationship to the permissible object. Metropolitan Milwaukee Association of Commerce, Inc. v. City of Milwaukee, 2011 WI App 45, 332 Wis. 2d 459, 798 N.W.2d 287, 09-1874. The fact that the regulation of sex offenders is a matter of statewide concern does not preclude municipalities from using their home-rule powers to impose further restrictions consistent with those imposed by the state. An ordinance regulating an area of statewide concern is preempted only if: 1) the legislature has expressly withdrawn the power of municipalities to act; 2) the ordinance logically conflicts with state legislation; 3) the ordinance defeats the purpose of state legislation; or 4) the ordinance violates the spirit of state legislation. City of South Milwaukee v. Kester, 2013 WI App 50, 347 Wis. 2d 334, 830 N.W.2d 710, 12-0724. A city probably can contract with a county to provide fire protection to a county institution located outside of boundaries of the city. 62 Atty. Gen. 84. A municipality has no jurisdiction over chemical treatment of waters to suppress aquatic nuisances. The department of natural resources is granted statewide supervision over aquatic nuisance control under s. 144.025(2) (i) [now s. 281.17(2)]. Applications for permits to chemically treat aquatic nuisances under s. 144.025(2) (i) may be denied even though statutory and regulatory requirements have been met if the chemical treatment would be counter-productive in achieving the goals set out in s. 144.025(1) [now s. 281.11]. 63 Atty. Gen. 260. Local units of government may not create and accumulate unappropriated surplus funds. However, a local unit of government may maintain reasonable amounts necessary in the exercise of sound business principles to meet the immediate cash flow needs of the municipality during the current budgetary period or to accumulate needed capital in non-lapsing funds to finance specifically identified future capital expenditures. 76 Atty. Gen. 77. Article VIII, section 5 restricts the state from levying taxes to create a surplus having no public purpose. Although the constitutional provision does not apply directly to municipalities, the same limitation applies indirectly to them because the state cannot delegate more power than it has. 76 Atty. Gen. 77. Conflicts between state statute and local ordinance in Wisconsin. 1975 WLR 840. Madison's Minimum-Wage Ordinance, Section 104.001, and the Future of Home Rule in Wisconsin. Burchill. 2007 WLR 151.