Mount Prospect, IL Building Setbacks & Zoning: Lot Coverage Limits (2026)
Key Facts
- R-1 residential lot coverage
- Impervious surfaces up to 45 percent
- R-1 nonresidential coverage
- Impervious surfaces up to 75 percent
- R-1 front and exterior side yard
- 45 percent of the required yard
- R-X residential coverage
- 35 percent under § 14.805 C
- R-A residential coverage
- 50 percent under § 14.1005 C
- Swimming pools
- Exempt from the lot coverage calculation
Summary
In the R-1 district, § 14.905 C caps total impervious surfaces at 45 percent of a lot for residential uses and 75 percent for nonresidential uses in the Village of Mount Prospect. The front and exterior side yards of a single-family residence are separately capped at 45 percent of the required yard.
C. Coverage Limitations:
1. Lot Coverage: No lot in the R-1 district shall be developed with total impervious surfaces exceeding forty five percent (45%) for permitted and conditional residential uses, or seventy five percent (75%) for permitted and conditional nonresidential uses.
2. Front And Exterior Side Yard Coverage: No front or exterior side yard of a single-family residence in the R-1 district shall be developed with total impervious surfaces exceeding forty five percent (45%) of the required yard.
Full Breakdown
Section 14.905 C sets two coverage tests for the R-1 district. The first, Lot Coverage, provides that no lot shall be developed with total impervious surfaces exceeding forty five percent (45%) for permitted and conditional residential uses, or seventy five percent (75%) for permitted and conditional nonresidential uses. The second, Front And Exterior Side Yard Coverage, provides that no front or exterior side yard of a single-family residence shall be developed with total impervious surfaces exceeding forty five percent (45%) of the required yard. Driveways and patios count against both tests because the measure is impervious surface, not building footprint.
Other districts print their own percentages. R-X (§ 14.805 C) allows 35 percent for residential uses and 75 percent for nonresidential, with a 35 percent cap on the required front and exterior side yard. R-A (§ 14.1005 C) allows 50 percent and 75 percent, with a 50 percent yard cap. R-2 (§ 14.1105 C) and R-3 (§ 14.1205 C) allow 50 percent residential and 75 percent nonresidential, with a 50 percent cap on front and exterior side yards of single-family residences. R-4 (§ 14.1304 C) caps impervious surfaces at 50 percent of the total lot area.
Business and industrial districts use a different measure. In B-3 (§ 14.1704 C) and I-1 (§ 14.2104 D), the total area of all buildings, structures and parking lots can be no more than seventy five percent of the total land area.
Accessory structures count. Section 14.306 B.3 provides that accessory structures shall be included in any maximum lot coverage calculation, while swimming pools are exempt from it. In residential districts a shed, gazebo, pergola or greenhouse is also limited to the smaller of two percent of the lot area or 200 square feet.
Violations & Fines
Section 14.905 prints no fine for excess coverage. A lot over the cap needs a variation, which under § 14.203 C.9 requires findings including a specific hardship distinguished from a mere inconvenience and a difficulty not created by the present owner. A conditional use for a setback reduction in Land Use Table 1 covers yards, not impervious coverage.
Frequently Asked Questions
How much of an R-1 lot can be paved or built over?
Is the coverage limit different in R-X and R-A?
Do sheds and garages count toward lot coverage?
What coverage applies in B-3 and I-1?
Sources & Official References
Other rules in Mount Prospect
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Lot Coverage Limits in Nearby Cities
How other cities in Cook County handle lot coverage limits.