Everything homeowners ask about building an ADU in Glendale — answered with 2026 data.
Yes, ADUs are allowed in Any lot or parcel where the zoning allows a single-family dwelling, provided the lot already contains a primary dwelling (Glendale Code 35.3.204.A.3). Not permitted on a lot with a duplex or other multiple-family development, whatever the zoning (A.4), and never before the main house is built (A.5) in Glendale, AZ. The maximum size for a detached ADU is Up to the floor area of the existing single-family dwelling, but never more than 1,000 sq ft (Glendale Code 35.3.204.A.16). That is more generous than the state floor, which only guarantees the lesser of 1,000 sq ft or 75% of the house (A.R.S. §9-461.18(A)(3)). Attached ADUs can be up to Same cap — up to the house's floor area, never more than 1,000 sq ft. Glendale has an ADU-friendliness score of 6/10. Check our full Glendale ADU rules page for complete zoning details.
ADU construction in Glendale typically costs $120,000-$245,000. The cost per square foot averages $145-$270. Garage conversions are more affordable at $55,000-$135,000, while prefab ADUs cost $85,000-$200,000. Permit fees add The city's own worked estimate for a 1,000 sq ft ADU (ADU handout, revised March 6, 2025): review fees of $1,370 (zoning clearance $144, building plan review $1,052.90, planning review $122.88, right-of-way review $35.88, record retention $14.04) plus permit fees of $2,034 (building permit $1,403.86, right-of-way permit $443.60, ¾-inch water meter set $126.73, fitting fee $60.19). Based on a city construction valuation of $120,750 for 1,000 sq ft to your budget. See our detailed Glendale ADU cost guide.
Detached ADUs in Glendale can be up to the floor area of the existing single-family dwelling, but never more than 1,000 sq ft. Attached ADUs are limited to Same cap — up to the house's floor area, never more than 1,000 sq ft. Junior ADUs (JADUs) have a cap of Not a category in Arizona — Glendale's ordinance has no junior ADU designation. Maximum height is The maximum height of the underlying zoning district — the ADU follows the district's building frontage, lot coverage and height limits (Glendale Code 35.3.204.A.12), and state law bars the city from holding an ADU to a stricter height than a house in the same zone (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 feet from the property line (Glendale Code 35.3.204.A.11(I)); state law caps what the city may require at 5 feet (A.R.S. §9-461.18(B)(6)). Side setback: 5 feet from the property line (Glendale Code 35.3.204.A.11(II)) — the state-law ceiling. Front setback: The front yard setback of the zoning district for the lot (Glendale Code 35.3.204.A.11(III)) — check your district in the Glendale Unified Development Code, or ask the planner assigned at zoning clearance. 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 (Glendale Code 35.3.204.A.20; A.R.S. §9-461.18(B)(3)). But the ADU may not have its own driveway or parking area separate from the main house (35.4.006). Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Required if either unit is rented: the owner (title holder or contract purchaser) must occupy the main house or the ADU as their principal residence, after which the other unit may be rented long- or short-term (Glendale Code 35.3.204.A.25). If neither is owner-occupied, the ADU may not be rented separately at all (A.26). Note the tension with state law, which bars a city from prohibiting separately leased long-term rental of either unit (A.R.S. §9-461.18(B)(1)) — the ordinance text is the city's own, no source we found resolves the conflict, so confirm with Glendale Planning before building an ADU to rent. Owners who had a legal right to build an ADU on or before September 14, 2024 are exempt from the residency requirement (A.26). 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 Glendale is typically Confirm with Glendale Planning — no published ADU review timeline found in a city source. Plan check: Full residential plan review under Glendale's building, fire and public-health codes (Glendale Code 35.3.204.A.22–23). State law bars a commercial building code or a fire-sprinkler requirement for an ADU (A.R.S. §9-461.18(D)). Budget for the separate city water meter: it needs a new tap to the main in the street or right-of-way, a right-of-way permit and a specially licensed contractor (35.3.204.A.24 and the city handout). Pre-approved plans availability: No city pre-approved ADU plan library found — confirm with Glendale Development Services.
Average ADU rental income in Glendale: 1-bedroom units rent for $1,050-$1,350/month, 2-bedroom units for $1,350-$1,700/month. Short-term rentals: Yes, if you live on site: once the owner occupies either the main house or the ADU as their principal residence, the other unit may be rented for periods shorter than 30 days (Glendale Code 35.3.204.A.25). Arizona TPT registration applies and Glendale may require a short-term rental licence — confirm with the city. If neither unit is owner-occupied, the ADU may not be rented separately at all, short- or long-term (A.26); see the owner-occupancy note for the state-law tension on the long-term side. Expected ROI: 5-8% annual return.
The minimum lot size for an ADU in Glendale is No ADU-specific minimum lot size — an ADU is allowed wherever a single-family dwelling is, and the district's lot coverage limit is the practical constraint. A lot of 1 acre or more unlocks a third unit (Glendale Code 35.3.204.A.10). 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 Glendale, a garage conversion typically costs $55,000-$135,000. 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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