New Berlin, WI Fence Regulations: Retaining Walls (2026)

Grading and drainage standards for the whole city sit in § 275-55, and subsection A(5) is the specific retaining-wall rule. New Berlin encourages natural slopes and grading over hard retaining structures, but once a wall exceeds 16 inches in height, an administrative permit from the Department of Community Development is required before it can be built; a wall reviewed and approved as part of a building permit does not need a separate use approval permit on top of that. Anything 16 inches or under is treated as a curb and falls outside this section entirely, and stepped walls with an overall gradient no steeper than three feet horizontal to one foot vertical are exempt regardless of total height.

The ordinance also sets out when a wall should even be considered: it is recommended only where the grade difference is more than two feet, or where the slope exceeds one foot vertical to three feet horizontal, and is favored for preserving significant natural features or trees. Placement is restricted too. A wall cannot sit closer than five feet to a side or rear lot line unless the Director of Community Development finds there is no other practical location and the affected neighbor gives written approval.

Design standards follow: walls must account for frost and hydrostatic pressure so the structure is not compromised, cannot disrupt the approved surface drainage or grading pattern, must be engineered and built so they will not collapse, and must be designed and sited so they do not negatively affect abutting properties. All retaining wall structures, including tiebacks, must sit entirely outside the district's base setback line.