Fairfield · Land use · Duplex
Where is a duplex allowed in Fairfield?
In Fairfield, a duplex is allowed in 8 base zones (RLM, RM, RH, CM, HD and 3 more, 2 with a condition), needs a conditional use permit in 6 (RL, CN, CO, CT, CC and 1 more, 4 with a condition) and not allowed in 6 (Fairfield use tables, read October 2026).
Key points
- Allowed: RLM, RM, RH, CM, HD, HO, HWT and HR
- Needs a permit: RL, CN, CO, CT, CC and HTD
- Not allowed: RVL, RVH, CS, CR, HDC and HPF
Find your lot's zone on the city zoning map, then read its row. Every status below was read from the Fairfield Municipal Code use tables (read October 2026). Base zones only. General information, not legal advice — check with the city before you apply.
Zones where a duplex can go
Fairfield's code calls this use “Duplex”. Each row links to the use table it comes from. A zone marked “see note” has a condition in the code, for example upper floors only or a larger lot.
| Zone | Status | Code |
|---|---|---|
| RLM | Allowed | § 25.20.2 |
| RM Residential, Medium Density | Allowed | § 25.20.2 |
| RH Residential, High Density | Allowed | § 25.20.2 |
| CM | Allowed — see note Note 3: Residential-only projects are allowed in the CM District. | § 25.22.2 |
| HD | Allowed — see note Note 11: Housing is not permitted on the first floor on Texas Street in the HD and HDC Zoning Districts. | § 25.23.2 |
| HO MU-O | Allowed | § 25.23.2 |
| HWT MU-WTS | Allowed | § 25.23.2 |
| HR | Allowed | § 25.23.2 |
| RL | Needs a conditional use permit | § 25.20.2 |
| CN | Needs a conditional use permit — see note Note 3: Residential-only projects are allowed in the CM District. | § 25.22.2 |
| CO | Needs a conditional use permit — see note Note 3: Residential-only projects are allowed in the CM District. | § 25.22.2 |
| CT | Needs a conditional use permit — see note Note 3: Residential-only projects are allowed in the CM District. | § 25.22.2 |
| CC | Needs a conditional use permit — see note Note 3: Residential-only projects are allowed in the CM District. | § 25.22.2 |
| HTD MU-TOD | Needs a conditional use permit | § 25.23.2 |
Zones where it is not allowed
What else applies
- Standards for this use: § 25.22.4.3.B.4 (cited by commercial Duplex row; section not in packet).
- Separate row 'Duet': S1 RLM P, RM P, RH P, others -; S2 CN C, CT C, CC C, CM P; S3 same as Duplex. Duet is not the main row.
- State law: SB 9 (Gov. Code § 65852.21) allows two homes on most single-family lots with a ministerial permit, also where this table says no.
- Not covered here: Zone names are not stated in the packet (only codes).; Heart of Fairfield zones HD and HDC have separate Ground / Upper floor columns. Where the two differ the cells are given as 'HD (ground floor)' / 'HD (upper floors)' (same for HDC); where equal one cell 'HD' / 'HDC'.; Any zone outside Tables 25-1, 25-9, 25-H1, 25-11, 25-13 (planned development / specific plan districts, if any) is not in the packet.; Section 25.50 definitions, Chapter 3 animal rules, 25.22.4.3 (residential in commercial zones), 25.24.3, 25.24.4.1 are cited by the tables but NOT in the packet.. Overlay zones and specific plans can also change the answer.
Other uses in Fairfield
Who this affects
Frequently asked questions
Can I have a duplex in the RL zone in Fairfield?
Only with a conditional use permit. Fairfield's use table lists it that way in RL (§ 25.20.2).
Can I have a duplex in the RVL zone in Fairfield?
No. Fairfield's use table does not allow it in RVL (§ 25.20.2).
Can I have a duplex in the RLM zone in Fairfield?
Yes. Fairfield's use table lists it as allowed in RLM (§ 25.20.2).
General information, not legal advice.
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