Everything homeowners ask about building an ADU in Peoria — answered with 2026 data.
Yes, ADUs are allowed in Any lot or parcel where the zoning allows a single-family dwelling (Peoria City Code §21-316.A and §21-316.D.1.a) — the R1-43, R1-35, R1-18, R1-12, R1-10, R1-8, R1-7 and R1-6 districts (§21-418.A, §21-422.B), plus Suburban Ranch (§21-411.A) and General Agriculture (§21-683.A) under Ord. 2024-20. Not permitted on a lot or parcel with a duplex or other multiple-family development (§21-316.D.1.b) in Peoria, AZ. The maximum size for a detached ADU is The lesser of 75% of the gross floor area of the existing single-family dwelling or 1,000 sq ft (Peoria City Code §21-316.C.2); 'gross floor area' means interior habitable area (§21-316.B). The ADU must be smaller than the house (§21-316.B definition) and counts toward the district's lot-coverage cap (§21-316.D.3). Attached ADUs can be up to Same cap — the lesser of 75% of the primary dwelling's gross floor area or 1,000 sq ft. Peoria has an ADU-friendliness score of 7/10. Check our full Peoria ADU rules page for complete zoning details.
ADU construction in Peoria typically costs $150,000-$280,000. The cost per square foot averages $175-$350. Garage conversions are more affordable at $80,000-$150,000, while prefab ADUs cost $150,000-$300,000. Permit fees add Valuation-based (Fee Table 27-6, Ord. 2025-28, 11-4-25): $1,045.25 for the first $100,000 of construction value plus $5.60 per $1,000 above it, plus plan check at 65% of the permit fee — about $2,190 on a $150,000 casita, before impact fees to your budget. See our detailed Peoria ADU cost guide.
Detached ADUs in Peoria can be up to The lesser of 75% of the gross floor area of the existing single-family dwelling or 1,000 sq ft. Attached ADUs are limited to Same cap — the lesser of 75% of the primary dwelling's gross floor area or 1,000 sq ft. Junior ADUs (JADUs) have a cap of Not a category in Arizona — Peoria City Code §21-316 has no junior ADU designation; a converted bedroom or garage is simply an attached ADU under the 75%/1,000 sq ft cap. Maximum height is Same height limit that applies to a single-family dwelling in the district (§21-316.D.4) — 30 ft in every R1 district, R1-43 through R1-6 (§21-420.A table). The 20-ft cap (25 ft in R1-18/R1-35) in §21-315.C.1 is for garages, sheds and other accessory buildings; ADUs are governed by §21-316 (§21-315.A.2). State law bars any ADU height limit stricter than the house's (A.R.S. §9-461.18(B)(5)). You are allowed up to 2 per lot — one attached plus one detached ADU on a qualifying lot.
Rear setback: 5 ft from the property line (Peoria City Code §21-316.D.2.a) — versus the 15-ft rear setback a house must keep in R1-18 through R1-6, 20 ft in R1-35 and 30 ft in R1-43 (§21-420.A). State law caps the ADU rear setback a city may require at 5 ft (A.R.S. §9-461.18(B)(6)). Side setback: 5 ft from the property line (Peoria City Code §21-316.D.2.a). A house needs 5 ft minimum/15 ft combined in R1-18 through R1-7 (5/8/13 in R1-6) and 10 ft in R1-35 and R1-43 (§21-420.A); the ADU rule drops the combined total and the 10-ft minimum. The 10-ft corner-lot street-side setback in §21-420.A is not expressly relaxed — confirm with Planning. State cap: 5 ft (A.R.S. §9-461.18(B)(6)). Front setback: The principal front building setback of the underlying district (Peoria City Code §21-316.D.2.b) — per §21-420.A, 20 ft in R1-18 through R1-6 with a front-facing garage (10 ft for a side-entry garage or the livable portion, with no more than 60% of the front elevation at 10 ft), 30 ft in R1-35 and 35 ft in R1-43. Nothing over 3 ft tall may stand in the required front setback (§21-419.A). Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
None — no additional parking space or in-lieu parking fee may be required for a new ADU (Peoria City Code §21-316.D.6; A.R.S. §9-461.18(B)(3)). Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Not required. Peoria's code has no owner-occupancy rule for ADUs, and state law bars the city from prohibiting separate long-term leasing (90 days or longer, or month-to-month) of the house or the ADU, or requiring any familial, marital, employment or other relationship between the occupants (A.R.S. §9-461.18(B)(1)-(2); §21-316.B 'Long-term Rental'). An ADU can never be sold separately from the house (§21-316.E.3). Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Peoria is typically Not published — no ADU review time frame could be verified from a city source (peoriaaz.gov sits behind a bot check). Fee Table 27-6 offers expedited plan check at 200% of the fee ($1,000 minimum); confirm current turnaround with Development & Engineering. Plan check: Full construction plan review under Peoria's building and fire codes and the Engineering Standards Manual (§21-316.A); plan check is billed at 65% of the building permit fee, and re-reviews after revisions at $220 for the first two hours (Fee Table 27-6). State law bars the city from applying a commercial building code to an ADU or requiring a fire sprinkler (A.R.S. §9-461.18(D)). An ADU may not sit on a public utility easement without written consent from every easement holder and affected utility (§21-316.D.7). Pre-approved plans availability: No city pre-approved ADU plan library could be verified as of September 2026 (Peoria's website was unreachable behind a bot check, and the code has no standard-plan section). A.R.S. §9-461.20 requires Peoria to make at least three pre-approved ADU plans available from July 1, 2026 — ask Development & Engineering whether the library is live.
Average ADU rental income in Peoria: 1-bedroom units rent for $1,400-$1,900/month, 2-bedroom units for $1,650-$2,300/month. Short-term rentals: Yes, with a City vacation rental permit (Peoria City Code §§11-148 to 11-161, Ord. Expected ROI: 6-11% gross rental yield.
The minimum lot size for an ADU in Peoria is No ADU-specific minimum lot size — an ADU is allowed wherever the zoning allows a single-family dwelling (§21-316.D.1.a), and state law bars a lot-size rule stricter than the house's (A.R.S. §9-461.18(B)(5)). The practical limit is maximum lot coverage, which the ADU counts toward (§21-316.D.3): 30% in R1-43, 35% in R1-35 and R1-18, 40% in R1-12, 45% in R1-10 through R1-6 (§21-420.A). A lot of 1 acre or more unlocks a third unit. This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Peoria, a garage conversion typically costs $80,000-$150,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.
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