Research by DoINeedAPermit Research Team · Updated May 2026
The Short Answer
Arizona law (ARS 34-226.1) requires a permit for every ADU, but Glendale's local zoning may allow ADUs where other Arizona cities don't. What matters is that the city cannot block you outright — state law has your back.
Glendale adopted a local ADU ordinance that permits detached ADUs, garage conversions, and junior ADUs on single-family lots — and crucially, Glendale does NOT require owner-occupancy of either unit, which sets it apart from many other Arizona municipalities that still cling to owner-occupancy rules. Arizona Revised Statute 34-226.1 mandates that cities allow at least one ADU per single-family lot (or junior ADU as an alternative), but individual cities can impose setbacks, lot-size thresholds, and parking rules that kill the deal. Glendale's code is relatively permissive: no minimum lot size for junior ADUs, setback rules are standard (typically 5 feet side/rear for detached units), and the city has waived parking requirements for ADUs under current state law amendments. The permit itself is mandatory — you cannot legally build without it — and will trigger full building review, utility plan sign-off, and a 60-90-day timeline depending on completeness. One wrinkle unique to Glendale: the city uses a combined flood-zone and monsoon-drainage overlay in some neighborhoods, which can add one or two weeks to plan review if your lot sits in an affected area. Check the city's online GIS tool before you design to confirm your parcel isn't flagged.

What happens if you skip the permit (and you needed one)

Glendale ADU permits — the key details

Arizona Revised Statute 34-226.1 is the hammer that guarantees your right to build an ADU in Glendale. The state law, effective 2019, prohibits cities from outright banning ADUs on single-family lots and requires that cities allow either a detached ADU or a junior ADU (or both). Glendale chose to allow both, plus garage conversions, which is more generous than required. However, the statute gives cities broad authority to impose 'reasonable' restrictions: lot-size minimums (Glendale has none for junior ADUs), setbacks (Glendale requires 5 feet side, 10 feet rear for detached units — standard for Arizona), and utilities (separate or sub-metered connections required). The permit threshold is absolute: ARS 34-226.1 explicitly requires that any ADU be 'constructed in compliance with applicable building codes,' which means Glendale Building Department will demand a full permit application, architectural plans, site plans, utility plans, and energy code compliance. No exceptions, no handwaivers. The only partial exemption is a junior ADU (typically under 800 square feet, no separate kitchen), which may qualify for streamlined review in some Arizona cities, but Glendale still requires a permit — just sometimes with a shorter plan-review window.

Glendale's unique angle is its relatively hands-off stance on parking and owner-occupancy. Many Arizona cities (Mesa, Chandler, Gilbert) still require owner-occupancy of the primary residence or the ADU, or both. Glendale dropped owner-occupancy requirements years ago, meaning you can build an ADU, live elsewhere, and rent both units as long as you own the land. Parking: Arizona cities often require 1–2 parking spaces per ADU. Glendale's code has been amended in recent years to align with state law (ARS 34-226.1 Section C prohibits cities from imposing parking on ADUs in certain zones), and Glendale does not enforce parking requirements for ADUs in most neighborhoods — a major cost-saver. However, the city still retains parking language in code for certain overlay zones (you'll see this if your parcel is in a historic or flood zone), so a quick phone call to the city's ADU coordinator (they have one) before you spend $2,000 on plans is worth it. The second wrinkle: Glendale's setback rules for detached ADUs are 5 feet side, 10 feet rear, and 25 feet front (if facing the street). A small lot (under 6,000 square feet) can accommodate a detached ADU, but you need to verify lot width and depth before you commit.

Utility connections and submeter requirements are where many ADU applications stumble in Glendale. The city and Glendale Water Department (separate entity) require that ADUs have either separate utility meters or a submeter system that tracks usage separately. For electric, this is straightforward: Arizona Public Service (APS) will run a new service or install a submeter; plan review time is 2–4 weeks. For water and sewer, Glendale Water Department requires a separate water meter and a separate sewer account, or a submeter that shows which unit's water flows where — the latter costs $1,500–$3,000 to install and maintain, while a separate meter costs $500–$1,200 for installation. Gas (if applicable) through Southwest Gas follows the same rule. Your architect or engineer MUST show these on the utility plan, or the permit will be incomplete and sent back for revision (adding 2–3 weeks). Plan to budget $3,000–$5,000 just for utility separation and meter installation. One gotcha: if you're converting an existing garage to an ADU, the city will require that you disconnect the existing garage electrical panel from the main house and install a new one for the ADU, adding $800–$1,500 to the build.

Egress (emergency exits) and foundation rules in Glendale follow IRC R310 and Arizona Amendments to the IBC. Every ADU must have a minimum 10 square foot emergency escape window or door on each sleeping room — non-negotiable. This kills some interior-conversion projects if the original structure has small, high windows that can't be enlarged. For detached ADUs, the city requires a frost-proof foundation, though Arizona's frost depth is minimal (3–6 inches in Glendale, negligible in most cases); however, the city still enforces IRC R403 (foundation inspection) because caliche (a hard lime-based layer) underlies much of Glendale, and a soil report may be required if the lot has known fill or caliche at shallow depth. Budget $300–$800 for a soil engineering report if your lot is in certain neighborhoods (north Glendale near the Verrado development, for example). Detached ADUs must also comply with IRC R310 for egress width (3-foot minimum door) and headroom (6 feet 8 inches minimum), which is standard but must be shown on plans. The city's plan-review checklist explicitly calls out egress and foundation, so don't skip these.

Timeline and fees in Glendale: permit fees are typically $4,000–$8,000 (based on a $150,000–$300,000 construction valuation), plus plan-review fees ($800–$1,500), plus utility connection fees ($500–$1,200), for a total of $5,300–$10,700 in direct permit costs. Add architect/engineer fees ($2,000–$5,000 for a junior ADU, $4,000–$8,000 for a detached ADU). Plan review takes 6–10 weeks if the application is complete; if incomplete, add 2–3 weeks per resubmission. The city does not currently have a SB 9-style pre-approved ADU plan program (California's shortcut), but Glendale has informally expedited junior ADU applications in the past — call the Building Department's ADU coordinator to ask if your project qualifies for expedited review. Inspections are full-scope: foundation, framing, rough trades, insulation, drywall, final, plus a planning (zoning) sign-off and utility inspection. Total build time: 12–20 weeks from permit issuance to final sign-off, assuming no delays and straightforward site conditions.

Three Glendale accessory dwelling unit (adu) scenarios

Scenario A
Junior ADU in rear corner of 7,000-sq-ft lot, Westgate neighborhood, Phoenix-style cinderblock construction
You own a standard Glendale suburban lot (7,000 square feet, 60-foot front, 115-foot depth) in the Westgate or Arrowhead Ranch area. You want to add a junior ADU (750 square feet) with one bedroom, a kitchenette (cooktop, sink, fridge), full bathroom, and a separate entrance. The structure will be a new concrete-block building matching the existing house's style. Because it's a junior ADU, the lot-size requirement is waived (Glendale has no minimum), and you're well clear of setback rules: 5-foot side setback is easily met with 15 feet of clearance, and 10-foot rear setback is met with 20 feet. Utilities are the main complexity. APS will run a new electric service ($500–$800); Glendale Water Department requires a separate water meter (not a submeter, because this is a new unit), costing $800–$1,200; sewer connection to the existing line will be permitted at $300–$500. Plan review is approximately 6–8 weeks because junior ADU plans are often streamlined. Permit fees are $4,500–$6,000 (based on $175,000 estimated valuation). Inspections: foundation (if concrete pad), framing, rough trades, drywall, final, plus utilities and planning. Total permit + fees: $5,800–$7,500. No parking requirement applies under state law. Timeline to final: 14–18 weeks from permit issuance.
Junior ADU | ≤800 sq ft | No owner-occupancy requirement | Separate water meter required | Permit fee $4,500–$6,000 | Total with utilities $5,800–$7,500 | Plan review 6–8 weeks | No parking required
Scenario B
Detached ADU on 5,500-sq-ft corner lot, downtown Glendale, soil caliche present, potential flood-overlay zone
You own a smaller corner lot (5,500 square feet) in downtown Glendale near Murphy Avenue and 60th Street, an area with older homes and some caliche-heavy soil. You want to build a detached ADU (900 square feet, one bedroom, full kitchen, full bathroom). This scenario showcases Glendale's flood and soil complexity. Step one: confirm your parcel is not in the city's flood-zone overlay (Glendale lies partially in a monsoon-drainage corridor, and some parcels near the Agua Fria River are flagged). If your lot is flagged, plan-review time extends by 2–3 weeks, and you may need to show that the ADU does not increase impervious surface beyond a certain threshold (typically 45% of lot coverage). Step two: soil. Your lot likely has caliche at 12–24 inches depth. Glendale's Building Department may require a geo/civil report ($500–$800) to confirm bearing capacity. A foundation engineer will likely recommend a post-and-pier or grade-beam system instead of a simple slab, adding $2,000–$3,500 to the build. Step three: setbacks are tight. A 5,500-sq-ft lot is roughly 55 feet wide by 100 feet deep. You need 5 feet side (both sides), 25 feet front (if facing the street), and 10 feet rear. That leaves you roughly 25 feet wide and 65 feet deep for the ADU footprint — a tight fit for 900 square feet. Utility connections: new electrical service from APS ($600–$800), separate water meter ($800–$1,200), sewer connection ($400–$600). Parking is waived. Plan review is 8–12 weeks because of the potential flood-zone overlay and soil report. Permit fees are $5,000–$7,500 (higher valuation due to caliche-driven foundation costs). Total permit + fees + soil report: $7,000–$10,500. Timeline to final: 18–22 weeks from permit.
Detached ADU | 900 sq ft | Possible flood-overlay review | Soil caliche report required | Geo engineer $500–$800 | Permit fee $5,000–$7,500 | Total with utilities $7,000–$10,500 | Plan review 8–12 weeks
Scenario C
Garage conversion to ADU, existing 2-car garage on 8,000-sq-ft lot, Verrado master-planned community, stucco frame structure
You own a home in the Verrado master-planned community (northwest Glendale, 8,000+ square feet typical) with a 400-sq-ft two-car attached garage. You want to convert the garage to a junior ADU (no separate kitchen, just a kitchenette with cooktop, sink, fridge; one bedroom, full bathroom, separate entrance into the side yard). This showcases a different local issue: master-planned community CC&Rs and the APS/utility infrastructure common to newer Glendale subdivisions. First, the CC&Rs. Verrado, Arrowhead Ranch, and other master-planned communities have homeowners associations that may prohibit or restrict ADUs in deed restrictions. Glendale law (ARS 34-226.1) does not preempt private HOA rules, so you must check your CC&Rs before you file. If the HOA objects, you have no legal recourse in Glendale. Assuming CC&Rs allow it, the build is straightforward. Garage conversion is classified as an 'alteration,' which still requires a full building permit. Key changes: rip out the overhead door and existing electrical panel, install a new entrance door (3-foot-wide, 6-foot-8-inch headroom), install a new 200-amp electrical panel or subpanel ($1,500–$2,000), and move the garage slab load-bearing wall to create proper egress (if required). New egress window (10 sq ft minimum) in the bedroom is usually required; existing garage windows rarely meet code. Utility plan: APS meter is often tricky in master-planned communities because the lot may share a transformer with neighbors; plan review may require coordination with APS for a separate service drop (2–3 weeks extra). Water and sewer: the existing lines run to the former garage; a separate meter is required ($800–$1,200). Permit fees are $3,500–$5,500 (lower valuation, existing structure). Plan review is 6–10 weeks (no soil report needed, no flood overlay in Verrado). Inspections: framing (new wall and door frame), electrical (new panel), rough trades, drywall, egress window verification, final, utilities. Timeline to final: 12–16 weeks. Unique to Verrado: the community's deed restrictions on setbacks and lot coverage are separate from Glendale's code; if you're in a covenant-controlled area, the HOA may require its own review before the city issues the permit, adding 2–4 weeks.
Garage conversion (junior ADU) | 400 sq ft | Check HOA CC&Rs first | No soil report | Electrical panel $1,500–$2,000 | Permit fee $3,500–$5,500 | Total with utilities $5,000–$7,500 | Plan review 6–10 weeks

Every project is different.

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Arizona State Law vs. Glendale Code: What You Win, What You Lose

Arizona Revised Statute 34-226.1, passed in 2019 and refined through 2023, is the gold standard for ADU law in the U.S. It overrides Glendale's zoning to the extent of conflict, meaning the city cannot ban ADUs or impose owner-occupancy rules. However, ARS 34-226.1 allows cities to impose 'reasonable' restrictions, and Glendale has done so strategically. Owner-occupancy: waived (Glendale allows rental). Parking: waived for ADUs under state law (Glendale does not enforce). Lot-size minimum for junior ADU: zero (state requirement; Glendale complies). Lot-size minimum for detached ADU: Glendale code says none, but practical lot size is 5,000+ square feet because of setback constraints. The state law guarantees you the right to build, but does not guarantee you a cheap or fast process.

Where Glendale tightens the screws: utilities. The city requires full separation (separate meters, not submeters) for water and sewer, which costs $1,500–$2,500. Many other Arizona cities allow submeters to save money. Setbacks: Glendale's 5-foot side, 10-foot rear, 25-foot front are standard Arizona, but a few cities allow 0-foot side setbacks for junior ADUs. Flood zones: Glendale's monsoon-overlay districts (near Agua Fria River, parts of northwest Glendale) add 2–4 weeks to review if your lot is flagged. Most Arizona cities don't have this overlay. The takeaway: Glendale is ADU-friendly by state standards, but not a speedboat. Budget 8–12 weeks for plan review and $5,500–$10,500 in total permit and utility costs.

Inspections and final sign-off in Glendale are thorough. The city requires a Planning/Zoning verification before the final building inspection, confirming that the ADU meets setback and lot-coverage rules. This step often surprises owners because it can flag last-minute issues (e.g., a lot-coverage calculation error) that force a revision. The city also requires a utility inspection by Glendale Water Department separately from the Building Department electrical/mechanical inspection. These three inspections (Planning, Utility, Building final) often cannot happen on the same day, stretching the final sign-off over 1–2 weeks. Factor this into your construction schedule.

Caliche, Expansive Soil, and Glendale's Foundation Wild Card

Glendale sits on a mix of desert terrain: caliche (a calcium-carbonate cemented layer) in the northern and western portions, and expansive clay in the southern valleys (closer to the Agua Fria floodplain). Caliche can be a gift or a curse. If it's at shallow depth (12–18 inches) and firm, it's an excellent bearing surface and costs nothing extra. If it's fractured, thin, or buried under fill material, you need a geotechnical report ($500–$800) and a revised foundation design, adding $2,000–$4,000 to construction. Expansive clay is more serious: it swells when wet and shrinks when dry, causing differential settlement. If your lot has clay, the engineer will likely recommend a post-and-pier system (not a slab) or a monolithic slab with rebar reinforcement, adding $3,000–$6,000 to the foundation.

Glendale's Building Department does not require a mandatory soil report for all ADUs, but the city's plan-review checklist triggers one if: the lot is in a known expansive-soil zone (south-central Glendale, near 59th Avenue and Northern), the lot is in a flood zone, the lot has a history of fill material, or the applicant's site plan suggests non-standard foundation (e.g., post-and-pier instead of slab). If you're unsure, call the Building Department's intake desk ($4.95/minute to a local number, or free via the online portal). A geotechnical report takes 2–3 weeks to produce and will cost you $500–$1,200 if your lot is flagged. Many ADU applicants in Glendale budget for this upfront to avoid a plan-review rejection.

Monsoon drainage is a second soil/site wild card. Glendale receives annual monsoons (July–September) with intense, short-duration rainfall. The city has enforced a monsoon-drainage overlay since 2015 that requires ADU sites to show how stormwater will be managed (retention, percolation, or drainage to a city channel). If your lot is in the overlay (check the city's GIS map), you must show on the site plan that the ADU does not increase impervious surface beyond 45%, or you must install a retention feature (swale, drywell, or retention pond). This adds 1–3 weeks to plan review and $1,000–$3,000 to site work. The overlay applies mostly to parcels near the Agua Fria River and in northwest Glendale near New River. If your lot is in downtown or south Glendale, this is unlikely to affect you.

City of Glendale Building Department
5850 West Glendale Avenue, Glendale, AZ 85301
Phone: (623) 930-2500 (main line; ask for Building Permits or ADU Coordinator) | https://www.glendaleaz.com/residents/building-permits (or search 'Glendale AZ permit portal')
Monday–Friday, 8:00 AM – 5:00 PM (verification recommended)

Common questions

Do I need owner-occupancy for an ADU in Glendale?

No. Arizona law (ARS 34-226.1) prohibits owner-occupancy requirements, and Glendale has dropped them. You can build an ADU and rent both the primary residence and the ADU without living in either unit. However, you must own the land (the ADU cannot be on a lot you lease). Verify your master-planned community's CC&Rs do not restrict this.

Is parking required for an ADU in Glendale?

No. State law prohibits parking requirements for ADUs in most cases (ARS 34-226.1, Section C), and Glendale does not enforce parking rules for ADUs. However, if your lot is in a designated overlay zone or historic district, the city may retain parking language in code; a phone call to Building Permits will confirm.

What is the difference between a junior ADU and a detached ADU in Glendale?

A junior ADU is a smaller unit (typically under 800 sq ft) with a kitchenette (cooktop, sink, fridge) but no separate entrance from outside — it uses an interior door from the main house or a side/rear entry. A detached ADU is a full second dwelling (up to 1,200 sq ft) with a complete kitchen, full bathroom, and a separate entrance. Both require permits in Glendale. Junior ADUs may qualify for expedited plan review (6–8 weeks); detached ADUs typically take 8–12 weeks because of complex setback and egress analysis.

How much does an ADU permit cost in Glendale?

Permit fees are $4,000–$8,000 (based on estimated construction valuation). Add $800–$1,500 for plan-review fees, $500–$1,200 for water/sewer meter installation, and $600–$800 for electrical service. Total direct costs: $5,500–$11,500. Architect/engineer fees for plans add another $2,000–$8,000 depending on complexity.

How long does plan review take for an ADU in Glendale?

Typical timeline is 6–10 weeks if your application is complete on first submission. If flagged for setback issues, soil, flood-zone overlay, or utility conflicts, expect 10–14 weeks. Incomplete applications are sent back for revision, adding 2–3 weeks per resubmission. Call the ADU Coordinator early to ask if your project qualifies for expedited review.

Can I convert my garage to an ADU in Glendale?

Yes. A garage conversion is treated as an alteration and requires a full permit. You must add an exterior entrance, an egress window (if a bedroom is present), and install a new electrical panel or subpanel. The converted unit must have separate utility meters (electric, water, sewer). Typical cost: $3,500–$7,500 in permit fees plus $3,000–$8,000 in construction. Check your HOA CC&Rs first; some master-planned communities prohibit garage conversions.

Do I need a separate water meter for my ADU, or can I use a submeter?

Glendale Water Department requires a separate water meter, not a submeter. A separate meter costs $800–$1,200 to install and assign a new account. Submeters save money but are not accepted by the city. Sewer must also be separately metered or accounted for; if you have a private septic system (rare in Glendale), a separate system is required.

What if my lot has caliche or expansive soil?

Glendale may require a geotechnical report ($500–$1,200) if your lot is in a known caliche or expansive-soil zone (south-central Glendale, or near the Agua Fria River floodplain). The engineer will recommend a post-and-pier or reinforced slab foundation, adding $2,000–$6,000 to construction. Call the Building Department to ask if a report is required before you spend money on plans.

Can I build an ADU if I live in a master-planned community like Verrado?

Maybe. Arizona law allows ADUs on single-family lots, but homeowners associations have the right to restrict ADUs through CC&Rs (deed restrictions). Check your CC&Rs and contact your HOA before you file a permit. Some master-planned communities explicitly allow ADUs; others prohibit them. If your HOA objects, you have no legal recourse under Glendale law.

Do I need to be a licensed contractor to build an ADU in Glendale?

No. Arizona Revised Statute 32-1121 allows owner-builders to construct residential structures without a license if the owner lives in the home and does not sell it for two years. However, most jurisdictions still require licensed contractors for certain trades (electrical, plumbing, HVAC) or for plan reviews that flag complex work. Ask Glendale Building Department if your project qualifies for owner-builder exemptions; if not, you'll need to hire licensed subs.

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Disclaimer: This guide is based on research conducted in May 2026 using publicly available sources. Always verify current accessory dwelling unit (adu) permit requirements with the City of Glendale Building Department before starting your project.

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