Tonawanda, NY Building Setbacks & Zoning: Lot Coverage Limits (2026)

Section 215-20.5 of the Town Board's Zoning Law sets dimensional and bulk standards for the town's three residential districts in Table 20-b: R-1 (single-family), R-2 (two-family) and MR (mixed residential). The "Max Lot Coverage" row limits "structures and impervious surfaces" to 60% of the lot in R-1 and R-2, and 50% in MR. Immediately below it, "Min Open Space" requires the remainder to be grass, landscaped or natural area: 40% in R-1 and R-2, and 50% in MR, so the two rows are mirror images that together account for the whole lot.

The table also states there shall be no more than one primary structure per lot, unless a different arrangement is approved through site plan review. Coverage is measured across the whole developed lot, meaning driveways, patios and accessory structures count toward the cap alongside the house itself, not just the building footprint. Because this is a numeric zoning standard rather than a discretionary use, compliance is checked when the Building Department reviews a permit application for new construction, additions, or expanded driveways and patios, and again during any site plan review under Section 215-20.3.

A design that exceeds 60% or 50% coverage cannot be approved as submitted; the applicant must either scale back the impervious area or seek relief from the Zoning Board of Appeals.