Any building which, under s. 66.0413 (1) (b) 1., has been declared so old, dilapidated or out of repair as to be dangerous, unsafe, unsanitary or otherwise unfit for human habitation or has been determined to be unreasonable to repair under s. 66.0413 (1) (b) 1. is a public nuisance and may be proceeded against under this chapter.
823.21.Dilapidated buildings declared nuisances.
Ch. 823: Nuisances · Last amended 1999 · Last verified July 15, 2026
In one sentenceSection 823.21 makes any building already declared dangerously dilapidated or unfit for habitation, or found unreasonable to repair, under section 66.0413(1)(b)1. into a public nuisance that can be pursued using chapter 823’s remedies.
Full Text of Section 823.21
Plain-English Summary
Section 823.21 links two bodies of law together. It does not itself set the standard for when a building is unsafe. Instead, it borrows a determination already made under section 66.0413(1)(b)1: that a building is so old, dilapidated, or out of repair that it is dangerous, unsafe, unsanitary, or otherwise unfit for human habitation, or that repairing it has been found unreasonable. Once that determination exists, the building becomes a public nuisance under this section.
The practical effect is to open up chapter 823’s remedies, including abatement orders and closure, for buildings that housing or building code officials have already flagged as dangerous, rather than requiring a separate nuisance case to prove the same dangerous condition from scratch. Section 823.215 does the same thing for dilapidated wharves and piers in navigable waters, using a parallel determination under section 30.13(5m)(a)2.
Frequently Asked Questions
What makes a building a public nuisance under this section?
A building already declared so old, dilapidated, or out of repair as to be dangerous, unsafe, unsanitary, or otherwise unfit for human habitation under section 66.0413(1)(b)1, or one found unreasonable to repair under that section.
Does a separate finding have to happen before section 823.21 applies?
Yes. The section relies on a declaration or determination already made under section 66.0413(1)(b)1.
What can be done once a building qualifies as a nuisance under this section?
It may be proceeded against under chapter 823, meaning the abatement and closure remedies elsewhere in the chapter become available.
Is there a similar rule for docks or piers instead of buildings?
Yes. Section 823.215 declares dilapidated wharves and piers in navigable waters a public nuisance in the same way, based on a determination under section 30.13(5m)(a)2.
Does this section require the building to be completely destroyed to qualify?
No. It reaches buildings declared dangerous, unsafe, unsanitary, or unfit for human habitation, or ones found unreasonable to repair, which does not require total destruction.
Amendment History
History: Sup. Ct. Order, 67 Wis. 2d 585, 762 (1975); Stats. 1975 s. 823.21; 1993 a. 213; 1999 a. 150.
Source & verification. Section text and official notes are
reproduced verbatim from the Wisconsin Statutes, published by the
Wisconsin Legislature (Legislative Reference Bureau). Last verified July 15, 2026.
· Official source
Also known as: wisconsin dilapidated building nuisanceunsafe building declared nuisance wisconsincondemned building nuisance chapter 823unfit for habitation nuisance wisconsin