Where is a duplex allowed in San Joaquin County?

Find your lot's zone on the city zoning map, then read its row. Every status below was read from the San Joaquin County Municipal Code use tables (read October 2026). Base zones only. General information, not legal advice — check with the city before you apply.

San Joaquin County'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.

R-R, R-VL, R-L, C-L, C-N, C-C, C-O, C-G, C-FS, C-RS, C-R, C-X, I-W, I-P, I-L, I-G, I-T, AG, AI, AL, AU, P-F, AP-X.

• R-L shows '-' for Duplex, but 9-200.040 (Two-unit Projects in the R-L Zone, not in packet) allows state-law two-unit projects there; the page should not say a duplex is flatly barred in R-L. Single-Unit Dwelling in all R zones.
• 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: Mountain House Development Title tables (S8-S12, Appendix 1; separate community zoning that REUSES zone codes such as R-VL, P-F, M-X). Cells from them were removed; a county page must not mix them in.; Planned Development zone (S7, 9-303.040): uses are set case by case, no table; Zone names (chapter intros not in packet); Definitions in Chapters 9-900/9-901 for 'Small', 'Large', 'School'. Overlay zones and specific plans can also change the answer.

• Single-family home
• Apartment building
• Live-work unit
• Residential care home (7 or more)
• Child care center
• Emergency shelter