Wis. Stat. § 299.95
The attorney general shall enforce chs. 281 to 285 and 289 to 295 and this chapter, except ss. 285.57 , 285.59 , and 299.64 , and all rules, special orders, licenses, plan approvals, permits, and water quality certifications of the department, except those promulgated or issued under ss. 285.57 , 285.59 , and 299.64 and except as provided in ss. 281.36(14) (f) , 285.86 and 299.85(7) (am) . Except as provided in s. 295.79(1) , the circuit court for Dane county or for any other county where a violation occurred in whole or in part has jurisdiction to enforce chs. 281 to 285 and 289 to 295 or this chapter or the rule, special order, license, plan approval, permit, or certification by injunctional and other relief appropriate for enforcement. For purposes of this proceeding where chs. 281 to 285 and 289 to 295 or this chapter or the rule, special order, license, plan approval, permit or certification prohibits in whole or in part any pollution, a violation is considered a public nuisance. The department of natural resources may enter into agreements with the department of justice to assist with the administration of chs. 281 to 285 and 289 to 295 and this chapter. Any funds paid to the department of justice under these agreements shall be credited to the appropriation account under s. 20.455(1) (k) .
Wis. Stat. § 299.95
That the violation of an order prohibiting pollution constitutes a public nuisance does not mean that there is no nuisance until an order is issued. State v. Dairyland Power Coop. 52 Wis. 2d 45, 187 N.W.2d 878 (1971). The state need not show irreparable harm to obtain an injunction under this section. State v. C. Spielvogel & Sons, 193 Wis. 2d 464, 535 N.W.2d 28 (Ct. App. 1995).