Marin County, CA Building Setbacks & Zoning: Setback Rules (2026)
Key Facts
- RA front setback
- 25 feet
- RA side setback
- 6 ft, 10 ft on street side
- RA rear setback
- 20% of lot depth, max 25 ft
- A20-A60 setbacks
- 50 ft front/side/rear
- Deck/porch projection allowed
- up to 6 ft into setback
- Governing table
- Development Code Table 2-5
- Base penalty
- misdemeanor, up to $500 fine
Summary
Unincorporated Marin sets minimum yard setbacks by zoning district in Development Code Table 2-5. In the RA district a structure must sit back 25 feet from the front line, 6 feet on each side (10 feet on a street side), and 20 percent of lot depth up to 25 feet from the rear, with a 30-foot height limit.
TABLE 2-5 RESIDENTIAL DISTRICT DEVELOPMENT STANDARDS. Zoning District: RA. Minimum Lot Area: 7,500 sq. ft. Maximum Residential Density: Not applicable. Minimum Setback Requirements: Front 25 ft.; Sides 6 ft., 10 ft. on street side; Rear 20% of lot depth to 25 ft. max. Height Limit: Primary 30 ft.; Accessory 16 ft. Maximum FAR: 0.30. RR RE R1 R2 RSP: Minimum Lot Area Not applicable; Maximum Residential Density See Zoning Map; Minimum Setback Requirements Not applicable; Height Limit Primary 30 ft., Accessory 16 ft.; Maximum FAR Not applicable.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Municipal Code: Supplement 2026 Update 1).
Full Breakdown
040 requires that development in the residential zoning districts conform to Table 2-5 (Residential District Development Standards). 30. The RR, RE, R1, R2 and RSP districts do not carry a fixed number in the table; setbacks for those districts are instead "Not applicable... See Zoning Map," meaning the applicable minimum is fixed parcel-by-parcel on the official zoning map rather than county-wide. 040: the A2 district matches RA's 25-foot front / 6-foot-and-10-foot side / 20-percent-of-depth rear formula, while the larger A3 through A15 districts step up to a flat 30-foot setback on all three sides, A15-A20 to 40 feet, and A20 through A60 to 50 feet on front, side and rear.
090 governs how every setback is actually measured: at right angles from the nearest property line to the nearest point of the wall, with special rules for flag lots, corner lots, and triangular or gore-shaped rear lines. That section also lists exemptions (site elements 18 inches or less above grade, code-compliant fences, retaining walls, small energy devices, flagpoles under 30 feet) and allowed encroachments under Table 3-1, such as a 6-foot deck or porch projection into a front or rear setback and a 30-inch chimney projection into any setback.
Detached accessory structures follow the primary structure's setback on front and sides but may come as close as the required side setback in the rear, capped at 10 feet.
Violations & Fines
Building or expanding within a required setback without Design Review or Variance approval is a Development Code violation. Under Marin County Code Section 1.04.270, violating any County Code provision not declared an infraction is a misdemeanor punishable by a fine of up to $500, up to six months in county jail, or both. The Community Development Agency can require removal or modification of noncompliant construction, and encroaching accessory structures may still qualify for after-the-fact Design Review approval under Chapter 22.42 rather than removal.
Frequently Asked Questions
How far must a house sit from the front property line in unincorporated Marin's RA district?
Do RR, RE, R1 and R2 parcels use the same setback numbers as RA?
Can a deck or porch extend into a required setback?
What happens if a structure is built inside the required setback without approval?
Sources & Official References
Other rules in Marin County
California rules heatmap·Compare Marin County to another location·View the California building setbacks & zoning overview
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