Unless otherwise provided by statute or agreement, every highway bridge on a city, village, or town boundary shall be repaired and maintained by any adjoining municipality in which the bridge is located. The cost of repairs and maintenance shall be paid by the adjoining municipalities in proportion to the last equalized valuation of the property in the adjoining municipalities.
Wis. Stat. § 82.23
2003 Wis. Act 214, which affected this section, contains extensive explanatory notes.