Wis. Stat. § 70.10 — Assessment, when made, exemption

The assessor shall assess all taxable property as of the close of January 1 of each year. Except in cities of the 1st class and 2nd class cities that have a board of assessors under s. 70.075 , the assessment shall be finally completed before the first Monday in April. All real property conveyed by condemnation or in any other manner to the state, any county, city, village or town by gift, purchase, tax deed or power of eminent domain before January 2 in such year shall not be included in the assessment. Assessment of manufacturing property subject to s. 70.995 shall be made according to that section.