Where is a duplex allowed in Diamond Bar?

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

Diamond Bar's code calls this use “Duplexes”. 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.

RR, RL, RLM.

• 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: Residential (Table 2-3), office (Table 2-5) and special purpose (Table 2-8) tables have no Emergency shelters row, so the use is not listed there (blank-equals-not-allowed rule; see 22.04.020(h), text not in packet).; TCSP and SP districts follow their specific plans.; Table 2-3 does not list the mixed-use (TCSP) and specific plan (SP) districts.. Overlay zones and specific plans can also change the answer.

• Emergency shelter
• Single-family home
• Bed and breakfast
• Child care center
• Private school