How New Berlin Handles Accessory Structures: A Practical Guide

New Berlin maintains 26 local ordinances across all categories, and 2 of those deal specifically with accessory structures. Here is a breakdown of what the city actually requires, what is prohibited, and where New Berlin falls on the strict-to-permissive spectrum compared to other cities.

Shed Rules

Sheds in New Berlin are accessory buildings under Section 275-42 of the New Berlin Zoning Code. Sheds 144 square feet or less may be located only in the side or rear yard, must be a minimum of 5 feet from all property lines if in the rear yard, must meet the underlying zoning district setbacks if in the side yard, and must be placed on a concrete slab, patio block, asphalt, polycarbonate base, or pressure-treated wood floor. A minimum of 10 feet of separation is required between the shed and any other structure (5 feet with proper fire separation approved by the Building Inspector).

Key details: Code Section: Sec. 275-42. Max Shed Size: 144 sq ft. Rear Yard Setback: 5 feet. Building Separation: 10 feet. Max Height: 18 ft / 1 story.

A shed installed in the front yard, inside the 5-foot rear-yard setback, without the required slab/patio-block/PT-wood floor, or in excess of the 144-square-foot threshold without an Accessory Buildings permit violates Section 275-42 and is enforceable by the New Berlin Building Inspections Division under the New Berlin Code Compliance program. Typical responses include a stop-work order, an order to relocate or remove the structure, and after-the-fact permit fees. A shed placed on septic-served property without prior Waukesha County approval may also be ordered moved by the Waukesha County Department of Parks & Land Use, Division of Environmental Health (262-896-8300).

ADU Rules

New Berlin restricts accessory dwelling units (ADUs) under Chapter 275 (Zoning) of the Municipal Code, adopted by Common Council Ordinance No. 2489 on June 17, 2013, under the city's zoning authority in Wis. Stat. Sec. 62.23. The Code defines an 'accessory dwelling' narrowly as a second dwelling unit integrated with a business on the same lot, and accessory dwelling units / living quarters are not permitted within accessory buildings (detached garages, sheds, etc.). Detached, freestanding ADUs in residential districts are not a recognized permitted use. Property owners seeking a second dwelling must work through the Department of Community Development for a use determination, conditional use, or rezoning.

Key details: Chapter 275 Zoning: Chapter 275 Zoning adopted June 17, 2013 by Ordinance No. 2489. City zoning authority: City zoning authority is Wis. Stat. Sec. 62.23. 'Accessory dwelling' defined: 'Accessory dwelling' defined as a second unit integrated with a business on. ADUs / living: ADUs / living quarters are not permitted within accessory buildings. Detached single-family ADUs: Detached single-family ADUs are not a recognized permitted use in standard residential.

Constructing or occupying an unapproved second dwelling unit, or converting an accessory building into living quarters, is a zoning violation under Chapter 275. Enforcement may include stop-work orders, daily forfeitures under the city's general penalty section, denial of occupancy, and required removal of the unauthorized kitchen, plumbing, or sleeping facilities. Renting an unpermitted accessory unit can also trigger building, electrical, and plumbing code violations under Wisconsin's Uniform Dwelling Code (SPS 320-325).

This is one of the stricter rules in New Berlin's municipal code. If you are unsure whether your situation complies, it is worth checking with the city before proceeding.

The Bottom Line

New Berlin's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming New Berlin is broadly strict or permissive.

These rules come from New Berlin's publicly available municipal code. For complete penalty schedules, exemption details, and answers to common questions, see the individual ordinance pages throughout this guide.