Quick Answer: No — in California, you generally cannot add an ADU to an individually-owned condo or townhouse as of 2025. California’s ADU laws (AB 68, SB 9, etc.) apply to properties with single-family or multi-family zoning classifications where the land is owned outright. Condos and townhouses in planned unit developments (PUDs) typically involve shared ownership of land through an HOA — the individual unit owner does not own the lot, so ADU law does not grant the right to build an additional structure on common land. Additionally, HOA CC&Rs (covenants, conditions, and restrictions) almost universally prohibit ADU construction. The exception: if you own a detached townhouse on a separate parcel of land (not a common interest development), you may be able to add an ADU — check with a land use attorney to confirm your property’s legal classification.
ADU Eligibility by Property Type — California 2025
Helpful Resources:
| Property Type | ADU Allowed? | Notes |
|---|---|---|
| Single-family home (owned lot) | Yes — state law requires it | Up to 1,200 sq ft; plus JADU allowed |
| Multi-family residential property (duplex, triplex) | Yes — up to 2 ADUs per lot | AB 2221/SB 897 |
| Condo (common interest development) | No — HOA owns common land | HOA CC&Rs prohibit external construction |
| Townhouse in PUD (HOA) | Generally no | Check whether land is separately owned |
| Detached townhouse on owned parcel | Possibly yes — verify legal status | Consult land use attorney |
Quartz Construction builds ADUs on single-family and eligible multi-family properties throughout San Jose. We verify eligibility before providing a quote. Learn about ADU services. CSLB #1003436 | Call (650) 749-7436.
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