Modesto, CA Building Setbacks & Zoning: Lot Coverage Limits (2026)

Table 4.1-1 in Modesto Code § 10-4.102 sets the maximum lot coverage for the three residential zones. In R-1 (Low-Density Residential) a building can cover no more than 50 percent of an interior lot and 55 percent of a corner lot. In R-2 (Medium-Density Residential) the limits are 55 percent interior and 60 percent corner. In R-3 (Medium-High-Density Residential) they are 60 percent interior and 65 percent corner. The corner-lot allowance is always exactly five percentage points above the interior figure, which reflects the extra street-side setback a corner lot has to give up. A typical 5,000 square foot R-1 interior lot, the minimum lot area in that zone, can therefore hold at most 2,500 square feet of covered structure. A 5,500 square foot R-1 corner lot, also its minimum, tops out at 3,025 square feet.

The table points to Section 10-2.141 for the definition. Lot coverage is the portion of a lot occupied by structures including patios, porches, garages, and covered parking spaces, measured from exterior walls or support posts. Accessory recreational and decorative structures such as gazebos, pergolas and wood decks do not count, and neither do impervious surfaces such as driveways, uncovered parking spaces, swimming pools and retaining walls. A roofed patio or carport counts against the cap; a concrete driveway or a pool does not.

Two cross-references change the arithmetic. First, the coverage row carries a note that accessory dwelling units are governed by Article 5, and Section 10-4.503(k) says that for an ADU of 800 square feet or less, lot coverage as shown on Table 4.1-1 shall not apply. A small ADU can be added even when the main house and garage already sit at the limit. Second, the accessory building rules in Section 10-4.114 limit a detached shed or workshop on an R-1 lot with only a single-family dwelling to 400 square feet or 50 percent of the main building on lots under 5,000 square feet, 600 square feet on lots of 5,000 to under 10,000, 800 on lots of 10,000 to under 20,000, and 1,000 on lots of 20,000 or more. That floor-area total is combined across multiple buildings and the table notes the buildings must still comply with lot coverage.

Coverage is only one of the Table 4.1-1 standards. The same table sets front setbacks of 15 feet for buildings, side setbacks of 5 feet for a one-story portion, a 10-foot rear setback for a one-story main building, and a maximum height of 2 stories or 30 feet in R-1 and R-2 and 3 stories or 42 feet in R-3, so the coverage cap rarely works alone. Lots 40,000 square feet or larger can ask for an exception on accessory building area under Section 10-9.502. Ambiguities in reading the table are decided by the Planning Director under Section 10-1.501.