Phoenix allows two ADUs on a single-family detached lot, with a possible third on a qualifying one-acre lot; a lot with a duplex or triplex may not add an ADU, and construction requires city permit approval.
ADU eligibility screen
Phoenix allows two ADUs on a single-family detached lot, with a possible third on a qualifying one-acre lot; a lot with a duplex or triplex may not add an ADU, and construction requires city permit approval.
Phoenix beginner's guide to ADUsHigh confidence
ADU eligibility screen
Phoenix allows two ADUs on a single-family detached lot, with a possible third on a qualifying one-acre lot; a lot with a duplex or triplex may not add an ADU, and construction requires city permit approval.
Lot size, existing units, ADU size, height, setbacks, lot coverage, parking, utilities, floodplain, code, deed restrictions, and owner-occupancy rules for some STR use remain separate.
What this tells youComputed rule answer
How precise this isComputed rule answer
Official data checkedPhoenix beginner's guide to ADUs
Next stepCheck parcel rules and project scope before design, purchase, or contractor conversations.
Single-family detached lotTwo ADUs allowed; a qualifying one-acre lot may support a third under the affordable-housing condition
Duplex or triplex lotNo additional ADU under the cited city guide
Before constructionCity permit approval plus lot, size, setback, coverage, utility, and code review
Confidence: HighComputed rule answerReviewed jurisdiction ruleReviewed July 2026
Phoenix beginner's guide to ADUs. Official agency pages remain final.
Can I act on this ADUAllowed result without checking the agency?
No. Lot size, existing units, ADU size, height, setbacks, lot coverage, parking, utilities, floodplain, code, deed restrictions, and owner-occupancy rules for some STR use remain separate. Use the official source link before making a legal, safety, construction, property, or financial decision.