Unincorporated Contra Costa County setback requirements

Corner lots: 15′ on the secondary street frontage.

Contra Costa County Ordinance Code §84-4 (4): front 20, side yards aggregate 15 with no single side under 5 (drawn 7.5 symmetric), second street frontage on a corner 15, rear 15. Side yards are stated as an AGGREGATE for both sides plus a minimum for any one side; the value drawn is the symmetric solution (aggregate ÷ 2), and one side may be narrowed to the single-side minimum if the other is widened to keep the aggregate. Accessory buildings and structures may reduce to 3 ft at the sides and rear once set back far enough from the front property line (50 ft in R-6/R-7/R-10, 65 ft in R-12/R-15/R-20, 75 ft in R-40/R-65, 65 ft in R-100) — so a landscape envelope drawn to the yards below is NOT the whole buildable area. An accessory building is capped at 500 sq ft on lots under 20,000 sq ft (600 sq ft above that) and 15 ft tall (§82-4.212), and may occupy at most 30 percent of a required rear yard (§82-14.006). A DETACHED ACCESSORY DWELLING UNIT TAKES 4 FT SIDE AND REAR (§82-24.012(h)(3)), and an internal conversion needs no setback at all — an ADU is permitted in every residential and agricultural district here. Where a rear yard abuts a neighbour's SIDE yard the rear may drop to 5 ft (§82-14.008). Landscape work is also subject to the state MWELO, adopted by reference at §82-26.002 with only the penalty clause amended. STILL UNCAPTURED from Division 82 and able to modify what is drawn: the yard definitions (§§82-4.284/.286/.288), lot dimensions and private-road structure setbacks (§82-4.244), obstructions permitted in yard areas (§82-14.002), and the legacy-lot side-yard rule for lots established before the ordinance (§82-14.004). The D-1 two-family district, the M-* multiple-family districts and P-1 planned units are not captured. Contra Costa County Ordinance Code Title 8 Division 84, print 2026-08-19. Verify with Contra Costa County DCD.

Corner lots: 15′ on the secondary street frontage.

Contra Costa County Ordinance Code §84-6 (6): front 20, side yards aggregate 15 with no single side under 5 (drawn 7.5 symmetric), second street frontage on a corner 15, rear 15. Side yards are stated as an AGGREGATE for both sides plus a minimum for any one side; the value drawn is the symmetric solution (aggregate ÷ 2), and one side may be narrowed to the single-side minimum if the other is widened to keep the aggregate. Accessory buildings and structures may reduce to 3 ft at the sides and rear once set back far enough from the front property line (50 ft in R-6/R-7/R-10, 65 ft in R-12/R-15/R-20, 75 ft in R-40/R-65, 65 ft in R-100) — so a landscape envelope drawn to the yards below is NOT the whole buildable area. An accessory building is capped at 500 sq ft on lots under 20,000 sq ft (600 sq ft above that) and 15 ft tall (§82-4.212), and may occupy at most 30 percent of a required rear yard (§82-14.006). A DETACHED ACCESSORY DWELLING UNIT TAKES 4 FT SIDE AND REAR (§82-24.012(h)(3)), and an internal conversion needs no setback at all — an ADU is permitted in every residential and agricultural district here. Where a rear yard abuts a neighbour's SIDE yard the rear may drop to 5 ft (§82-14.008). Landscape work is also subject to the state MWELO, adopted by reference at §82-26.002 with only the penalty clause amended. STILL UNCAPTURED from Division 82 and able to modify what is drawn: the yard definitions (§§82-4.284/.286/.288), lot dimensions and private-road structure setbacks (§82-4.244), obstructions permitted in yard areas (§82-14.002), and the legacy-lot side-yard rule for lots established before the ordinance (§82-14.004). The D-1 two-family district, the M-* multiple-family districts and P-1 planned units are not captured. Contra Costa County Ordinance Code Title 8 Division 84, print 2026-08-19. Verify with Contra Costa County DCD.

Corner lots: 15′ on the secondary street frontage.

Contra Costa County Ordinance Code §84-8 (8): front 20, side yards aggregate 20 with no single side under 10 (drawn 10 symmetric), second street frontage on a corner 15, rear 15. Side yards are stated as an AGGREGATE for both sides plus a minimum for any one side; the value drawn is the symmetric solution (aggregate ÷ 2), and one side may be narrowed to the single-side minimum if the other is widened to keep the aggregate. Accessory buildings and structures may reduce to 3 ft at the sides and rear once set back far enough from the front property line (50 ft in R-6/R-7/R-10, 65 ft in R-12/R-15/R-20, 75 ft in R-40/R-65, 65 ft in R-100) — so a landscape envelope drawn to the yards below is NOT the whole buildable area. An accessory building is capped at 500 sq ft on lots under 20,000 sq ft (600 sq ft above that) and 15 ft tall (§82-4.212), and may occupy at most 30 percent of a required rear yard (§82-14.006). A DETACHED ACCESSORY DWELLING UNIT TAKES 4 FT SIDE AND REAR (§82-24.012(h)(3)), and an internal conversion needs no setback at all — an ADU is permitted in every residential and agricultural district here. Where a rear yard abuts a neighbour's SIDE yard the rear may drop to 5 ft (§82-14.008). Landscape work is also subject to the state MWELO, adopted by reference at §82-26.002 with only the penalty clause amended. STILL UNCAPTURED from Division 82 and able to modify what is drawn: the yard definitions (§§82-4.284/.286/.288), lot dimensions and private-road structure setbacks (§82-4.244), obstructions permitted in yard areas (§82-14.002), and the legacy-lot side-yard rule for lots established before the ordinance (§82-14.004). The D-1 two-family district, the M-* multiple-family districts and P-1 planned units are not captured. Contra Costa County Ordinance Code Title 8 Division 84, print 2026-08-19. Verify with Contra Costa County DCD.

Corner lots: 15′ on the secondary street frontage.

Contra Costa County Ordinance Code §84-10 (10): front 20, side yards aggregate 25 with no single side under 10 (drawn 12.5 symmetric), second street frontage on a corner 15, rear 15. Side yards are stated as an AGGREGATE for both sides plus a minimum for any one side; the value drawn is the symmetric solution (aggregate ÷ 2), and one side may be narrowed to the single-side minimum if the other is widened to keep the aggregate. Accessory buildings and structures may reduce to 3 ft at the sides and rear once set back far enough from the front property line (50 ft in R-6/R-7/R-10, 65 ft in R-12/R-15/R-20, 75 ft in R-40/R-65, 65 ft in R-100) — so a landscape envelope drawn to the yards below is NOT the whole buildable area. An accessory building is capped at 500 sq ft on lots under 20,000 sq ft (600 sq ft above that) and 15 ft tall (§82-4.212), and may occupy at most 30 percent of a required rear yard (§82-14.006). A DETACHED ACCESSORY DWELLING UNIT TAKES 4 FT SIDE AND REAR (§82-24.012(h)(3)), and an internal conversion needs no setback at all — an ADU is permitted in every residential and agricultural district here. Where a rear yard abuts a neighbour's SIDE yard the rear may drop to 5 ft (§82-14.008). Landscape work is also subject to the state MWELO, adopted by reference at §82-26.002 with only the penalty clause amended. STILL UNCAPTURED from Division 82 and able to modify what is drawn: the yard definitions (§§82-4.284/.286/.288), lot dimensions and private-road structure setbacks (§82-4.244), obstructions permitted in yard areas (§82-14.002), and the legacy-lot side-yard rule for lots established before the ordinance (§82-14.004). The D-1 two-family district, the M-* multiple-family districts and P-1 planned units are not captured. Contra Costa County Ordinance Code Title 8 Division 84, print 2026-08-19. Verify with Contra Costa County DCD.

Corner lots: 20′ on the secondary street frontage.

Contra Costa County Ordinance Code §84-14 (14): front 25, side yards aggregate 35 with no single side under 15 (drawn 17.5 symmetric), second street frontage on a corner 20, rear 15. Side yards are stated as an AGGREGATE for both sides plus a minimum for any one side; the value drawn is the symmetric solution (aggregate ÷ 2), and one side may be narrowed to the single-side minimum if the other is widened to keep the aggregate. Accessory buildings and structures may reduce to 3 ft at the sides and rear once set back far enough from the front property line (50 ft in R-6/R-7/R-10, 65 ft in R-12/R-15/R-20, 75 ft in R-40/R-65, 65 ft in R-100) — so a landscape envelope drawn to the yards below is NOT the whole buildable area. An accessory building is capped at 500 sq ft on lots under 20,000 sq ft (600 sq ft above that) and 15 ft tall (§82-4.212), and may occupy at most 30 percent of a required rear yard (§82-14.006). A DETACHED ACCESSORY DWELLING UNIT TAKES 4 FT SIDE AND REAR (§82-24.012(h)(3)), and an internal conversion needs no setback at all — an ADU is permitted in every residential and agricultural district here. Where a rear yard abuts a neighbour's SIDE yard the rear may drop to 5 ft (§82-14.008). Landscape work is also subject to the state MWELO, adopted by reference at §82-26.002 with only the penalty clause amended. STILL UNCAPTURED from Division 82 and able to modify what is drawn: the yard definitions (§§82-4.284/.286/.288), lot dimensions and private-road structure setbacks (§82-4.244), obstructions permitted in yard areas (§82-14.002), and the legacy-lot side-yard rule for lots established before the ordinance (§82-14.004). The D-1 two-family district, the M-* multiple-family districts and P-1 planned units are not captured. Contra Costa County Ordinance Code Title 8 Division 84, print 2026-08-19. Verify with Contra Costa County DCD.

Corner lots: 20′ on the secondary street frontage.

Contra Costa County Ordinance Code §84-16 (16): front 25, side yards aggregate 40 with no single side under 20 (drawn 20 symmetric), second street frontage on a corner 20, rear 15. Side yards are stated as an AGGREGATE for both sides plus a minimum for any one side; the value drawn is the symmetric solution (aggregate ÷ 2), and one side may be narrowed to the single-side minimum if the other is widened to keep the aggregate. Accessory buildings and structures may reduce to 3 ft at the sides and rear once set back far enough from the front property line (50 ft in R-6/R-7/R-10, 65 ft in R-12/R-15/R-20, 75 ft in R-40/R-65, 65 ft in R-100) — so a landscape envelope drawn to the yards below is NOT the whole buildable area. An accessory building is capped at 500 sq ft on lots under 20,000 sq ft (600 sq ft above that) and 15 ft tall (§82-4.212), and may occupy at most 30 percent of a required rear yard (§82-14.006). A DETACHED ACCESSORY DWELLING UNIT TAKES 4 FT SIDE AND REAR (§82-24.012(h)(3)), and an internal conversion needs no setback at all — an ADU is permitted in every residential and agricultural district here. Where a rear yard abuts a neighbour's SIDE yard the rear may drop to 5 ft (§82-14.008). Landscape work is also subject to the state MWELO, adopted by reference at §82-26.002 with only the penalty clause amended. STILL UNCAPTURED from Division 82 and able to modify what is drawn: the yard definitions (§§82-4.284/.286/.288), lot dimensions and private-road structure setbacks (§82-4.244), obstructions permitted in yard areas (§82-14.002), and the legacy-lot side-yard rule for lots established before the ordinance (§82-14.004). The D-1 two-family district, the M-* multiple-family districts and P-1 planned units are not captured. Contra Costa County Ordinance Code Title 8 Division 84, print 2026-08-19. Verify with Contra Costa County DCD.

Corner lots: 20′ on the secondary street frontage.

Contra Costa County Ordinance Code §84-38 (38): front 25, side yards aggregate 40 with no single side under 20 (drawn 20 symmetric), second street frontage on a corner 20, rear 15. Buildings housing livestock, bees, birds or poultry must also stand at least 50 ft from the boundary of any residential district (§84-38.1002). Side yards are stated as an AGGREGATE for both sides plus a minimum for any one side; the value drawn is the symmetric solution (aggregate ÷ 2), and one side may be narrowed to the single-side minimum if the other is widened to keep the aggregate. Accessory buildings and structures may reduce to 3 ft at the sides and rear once set back far enough from the front property line (50 ft in R-6/R-7/R-10, 65 ft in R-12/R-15/R-20, 75 ft in R-40/R-65, 65 ft in R-100) — so a landscape envelope drawn to the yards below is NOT the whole buildable area. An accessory building is capped at 500 sq ft on lots under 20,000 sq ft (600 sq ft above that) and 15 ft tall (§82-4.212), and may occupy at most 30 percent of a required rear yard (§82-14.006). A DETACHED ACCESSORY DWELLING UNIT TAKES 4 FT SIDE AND REAR (§82-24.012(h)(3)), and an internal conversion needs no setback at all — an ADU is permitted in every residential and agricultural district here. Where a rear yard abuts a neighbour's SIDE yard the rear may drop to 5 ft (§82-14.008). Landscape work is also subject to the state MWELO, adopted by reference at §82-26.002 with only the penalty clause amended. STILL UNCAPTURED from Division 82 and able to modify what is drawn: the yard definitions (§§82-4.284/.286/.288), lot dimensions and private-road structure setbacks (§82-4.244), obstructions permitted in yard areas (§82-14.002), and the legacy-lot side-yard rule for lots established before the ordinance (§82-14.004). The D-1 two-family district, the M-* multiple-family districts and P-1 planned units are not captured. Contra Costa County Ordinance Code Title 8 Division 84, print 2026-08-19. Verify with Contra Costa County DCD.