Contra Costa County · Zoning · O-1
Contra Costa County O-1 zoning: height, setbacks and lot size
In Contra Costa County's O-1 zone, generally buildings can be up to 35 ft tall and the front setback is 20 ft, with the conditions listed below (Contra Costa County code, read October 2026).
Key points
- Maximum building height: 35 ft
- Minimum front setback: 20 ft (on corner lots the other street side setback is 15 ft)
- Minimum side setback: 5 ft (15 ft minimum where a side yard abuts a residential land use district; aggregate side yards must total at least 15 ft)
- Maximum lot coverage: 35%
O-1 (LIMITED OFFICE DISTRICT) is a zoning district in Contra Costa County. Every value below was read from the Contra Costa 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 O-1
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.
| Maximum building height | 35 ft § 84-44.802 · code textNo building or structure permitted in the O-1 district shall exceed two and one-half stories or thirty-five feet in height. |
|---|---|
| Minimum front setback | 20 ft Applies: on corner lots the other street side setback is 15 ft § 84-44.1004 · code textThere shall be a setback (front yard) of at least twenty feet for any building or structure in the O-1 district; on corner lots, the principal frontage of the lot shall have a setback of at least twenty feet and the other setback shall be at least fifteen feet. |
| Minimum side setback | 5 ft Applies: 15 ft minimum where a side yard abuts a residential land use district; aggregate side yards must total at least 15 ft § 84-44.1002 · code textThere shall be an aggregate side yard width of at least fifteen feet with no single side yard being less than five feet in width, except that when a side yard abuts a residential land use district, it shall then have a minimum width of fifteen feet with a minimum of five-foot width on the other side. |
| Maximum lot coverage | 35% § 84-44.608 · code textNo buildings or structures permitted in the O-1 district shall cover more than thirty-five percent of the lot area. |
When a different number applies
The code sets other values for particular lots, buildings or locations in O-1:
- Minimum front setback: 15 ft — On corner lots, the setback on the frontage other than the principal frontage § 84-44.1004
- Minimum side setback: 15 ft aggregate — Aggregate side yard width § 84-44.1002
- Minimum side setback: 15 ft — When a side yard abuts a residential land use district § 84-44.1002
Not on this page
We did not find a general stories, rear setback, lot size, FAR, density limit for O-1 in the zoning tables we read. The code may still set one elsewhere — check the Contra Costa County Municipal Code.
Other Contra Costa County zoning districts
Who this affects
Frequently asked questions
What is the maximum building height in Contra Costa County's O-1 zone?
35 ft — Contra Costa County Municipal Code § 84-44.802.
What is the minimum front setback in Contra Costa County's O-1 zone?
20 ft (on corner lots the other street side setback is 15 ft) — Contra Costa County Municipal Code § 84-44.1004.
What is the minimum side setback in Contra Costa County's O-1 zone?
5 ft (15 ft minimum where a side yard abuts a residential land use district; aggregate side yards must total at least 15 ft) — Contra Costa County Municipal Code § 84-44.1002.
What is the maximum lot coverage in Contra Costa County's O-1 zone?
35% — Contra Costa County Municipal Code § 84-44.608.
General information, not legal advice.
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