Wisconsin Security Deposit Law (Wis. Stat. § 704.28 / ATCP 134.06)

Wis. Stat. § 704.28(4) requires a landlord to "deliver or mail to a tenant the full amount of any security deposit paid by the tenant, less any amounts that may be withheld" within 21 days after the lease ends, the tenant surrenders the premises, or a new tenant moves in early, whichever applies. Permitted deductions under § 704.28(1)-(2) include tenant damage, waste, or neglect; unpaid rent for which the tenant is legally responsible; unpaid utility charges; and certain municipal permit fees. Section 704.28(3) provides that the law "does not authorize a landlord to withhold any amount from a security deposit for normal wear and tear." Wis. Admin. Code ATCP 134.06 requires that when any portion is withheld the landlord deliver or mail a written statement accounting for all amounts withheld, describing each item, within the same 21-day window.

Withholding a deposit improperly violates ATCP 134, an order issued under Wis. Stat. § 100.20. Under § 100.20(5) a tenant suffering pecuniary loss "shall recover twice the amount of such pecuniary loss, together with costs, including a reasonable attorney fee" — double damages plus costs and attorney fees.