Mount Prospect, IL Fence Regulations: Retaining Walls (2026)

Retaining walls in the Village of Mount Prospect are regulated through the permitted obstructions section of the zoning chapter, § 14.319, rather than through a stand-alone wall ordinance. Subsection A opens by saying that for all zoning districts other than C-R, the listed regulations apply to structures located within the required yards. The C-R District is handled separately in article VII of the chapter.

The table row reads: landscape terraces and retaining walls, subject to approval by the Engineering Division and issuance of a building permit. Two gates therefore apply: Engineering Division approval, then a building permit. The table prints no height figure for retaining walls, so no numeric height cap appears in this row.

Subsection B.1 requires permitted obstructions to comply with the requirements for impervious surface and floor area ratio as defined in the chapter, with an exception for outdoor storage cabinets, decorative outdoor structures, rain barrels, arbors and trellises. Retaining walls are not on that exception list. Subsection B.2 exempts a similar list from building permits, and again retaining walls are absent, which matches the building permit condition printed in the table row itself.

Subsection B.3 states that permitted obstructions listed in the section do not contribute to the total number of accessory structures permitted per lot under § 14.306.

The zoning definitions in § 14.2401 describe a retaining wall as a freestanding structure designed and constructed to support a mass of earth or resist lateral earth pressures. Separately, § 14.318.A treats freestanding walls as fences for purposes of the fence permit. Section 14.318.C.4 adds that grades at property lines cannot be altered unless a grading plan is submitted to and approved by the Community Development Director.