Sonoma County · Zoning · R3
Sonoma County R3 zoning: height, setbacks and lot size
In Sonoma County's R3 zone, the front setback is 15 ft and the minimum lot size is 6,000 sq. ft. (Sonoma County code, read October 2026).
Key points
- Minimum front setback: 15 ft
- Minimum side setback: 5 ft
- Minimum rear setback: 10 ft
- Minimum lot size: 6,000 sq. ft.
- Maximum lot coverage: 60%
- Maximum density: 12 to 20 units per acre (the code sets a range: at least 12, at most 20 units per acre)
R3 (R3 Zone) is a zoning district in Sonoma County. Every value below was read from the Sonoma County Municipal Code and links to its section (read October 2026). State laws such as the ADU and SB 9 rules can allow more on a residential lot. General information, not legal advice — read the code text and check with the city before you build.
Development standards in R3
The general rule for a typical lot in this zone. Zoning tables often attach notes, such as rules for corner lots, lots next to a residential zone, or new subdivisions only. Open “code text” under a value to see the table cell or sentence it was read from.
| Minimum front setback | 15 ft § 26-08-040 · code textTable row “Front Property Line Setback (min. ft.)”, column “R3 Zone”: 15 |
|---|---|
| Minimum side setback | 5 ft § 26-08-040 · code textTable row “Interior Side Property Line Setback (min. ft.)”, column “R3 Zone”: 5 |
| Minimum rear setback | 10 ft § 26-08-040 · code textTable row “Rear Property Line Setback (min. ft.)”, column “R3 Zone”: 10 |
| Minimum lot size | 6,000 sq. ft. § 26-08-040 · code textTable row “Lot Size (min. sq. ft.)”, column “R3 Zone”: 6,000 |
| Maximum lot coverage | 60% § 26-08-040 · code textTable row “Lot Coverage (max.)”, column “R3 Zone”: 60% |
| Maximum density | 12 to 20 units per acre Applies: the code sets a range: at least 12, at most 20 units per acre § 26-08-040 · code textTable row “Max. Dwelling Units per Acre (max.)”, column “R3 Zone”: 12-20 |
Uses in R3
Uses the code's use tables allow in R3, or allow with a permit. Each links to its page with the code section.
- Single-family home — Allowed
- Duplex — Allowed
When a different number applies
The code sets other values for particular lots, buildings or locations in R3:
- Maximum building height: 40 ft — Also at most 3 stories; with design review approval for type A housing opportunity area projects or mostly tuck-under (podium) parking § 26-08-040
- Maximum building height: 30 ft — buildings within thirty feet of an abutting R1 or RR zone § 26-08-040
- Maximum number of stories: 3 stories — design review approval for housing opportunity area type "A" projects or projects where the majority of resident parking is provided as tuck-under (podium-style) ground floor parking § 26-08-040
- Minimum side setback: 10 ft — lots where access is gained to an interior court by way of a side yard, or where an entrance to a building faces the sideline § 26-08-040
Not on this page
We did not find a general height, stories, FAR limit for R3 in the zoning tables we read. The code may still set one elsewhere — check the Sonoma County Municipal Code.
Other Sonoma County zoning districts
Who this affects
Frequently asked questions
What is the minimum front setback in Sonoma County's R3 zone?
15 ft — Sonoma County Municipal Code § 26-08-040.
What is the minimum side setback in Sonoma County's R3 zone?
5 ft — Sonoma County Municipal Code § 26-08-040.
What is the minimum rear setback in Sonoma County's R3 zone?
10 ft — Sonoma County Municipal Code § 26-08-040.
What is the minimum lot size in Sonoma County's R3 zone?
6,000 sq. ft. — Sonoma County Municipal Code § 26-08-040.
What is the maximum lot coverage in Sonoma County's R3 zone?
60% — Sonoma County Municipal Code § 26-08-040.
General information, not legal advice.
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