When any new drain is connected to an existing district drain, whether or not the area drained by the new drain is within the drainage district, the drainage board by order may assess against the newly drained land a reasonable share of the cost of constructing the existing district drain. If an assessment is made under this section and the area drained by the new drain is not within the drainage district, the drainage board shall proceed under s. 88.78 to annex the land to the drainage district.
Wis. Stat. § 88.405
1993 Wis. Act 456, which creates this section, contains extensive explanatory notes.