Madison, WI Fence Regulations: Retaining Walls (2026)

15(1)(a) declares that private use of City-owned or leased greenways and park lands, including fences, retaining walls, outbuilding sites, dog runs, play equipment, gardens, storage of piers or boat hoists, dumping yard waste, tree work and lawn chemical treatment, is a public nuisance and prohibited unless the owner obtains approval under the section's exceptions or a valid permit under Sec. 10 or Sec. 33, MGO. Subsection (1)(c), 'Permissible Use of Certain Greenways,' opens a narrow path within eligible greenways where the proposal, in the City Engineer's opinion, doesn't impede water flow or create a risk of flotation, and complies with any other City ordinance requirement and any limits the City Engineer imposes.

Even inside that path, retaining walls get the strictest treatment on the list: item (e) says retaining walls of any size, whether gravity walls or poured concrete or mortared stone/masonry, are only allowed with a valid Greenway Privilege issued under Sec. 05(11), the same permit gate applied to permanent fencing and constructed stairs in a greenway. A similar public-nuisance bar applies to retaining walls built in the Southwest Path corridor. This is a land-use control tied specifically to City-owned or leased greenway and park property; it does not set a general citywide height, permit or engineering standard for a retaining wall built entirely on private property away from a greenway.