Cost Guide

How Much Does an ADU Cost in Glendale, AZ?

Complete 2026 cost breakdown: construction, permits, financing, and expected rental ROI.

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New Construction
$120,000-$245,000
Garage Conversion
$55,000-$135,000
Prefab ADU
$85,000-$200,000
Cost Per Sq Ft
$145-$270

Construction Cost Breakdown

Building an ADU in Glendale costs between $120,000-$245,000 for new construction, with per-square-foot costs averaging $145-$270. These figures include design, permitting, site preparation, and construction. The most affordable option is a garage conversion at $55,000-$135,000, while prefab/modular ADUs fall in between at $85,000-$200,000.

Cost CategoryEstimated Range
Architectural Plans$3,000 – $15,000
Permits & FeesThe 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
Impact FeesYes, and they are most of the bill: $9,630 for a detached ADU (water $3,330, sewer $3,795, parks $936, police $719, fire $655, libraries $195), which pays the single-family schedule, and $8,780 for an attached ADU on the lower multifamily schedule. No streets impact fee — state law forbids it. All-in city estimate for 1,000 sq ft: $13,034 detached, $12,184 attached (City of Glendale ADU handout, revised 3/6/2025)
Site Prep & Foundation$10,000 – $35,000
Framing & Structure$15,000 – $45,000
Plumbing$8,000 – $20,000
Electrical$5,000 – $15,000
HVAC$3,000 – $8,000
Interior Finishes$15,000 – $40,000

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Permit Costs & Timeline

Permit fees in Glendale are 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. The review timeline is Confirm with Glendale Planning — no published ADU review timeline found in a city source, with 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). Impact fees are Yes, and they are most of the bill: $9,630 for a detached ADU (water $3,330, sewer $3,795, parks $936, police $719, fire $655, libraries $195), which pays the single-family schedule, and $8,780 for an attached ADU on the lower multifamily schedule. No streets impact fee — state law forbids it. All-in city estimate for 1,000 sq ft: $13,034 detached, $12,184 attached (City of Glendale ADU handout, revised 3/6/2025). Pre-approved plans: No city pre-approved ADU plan library found — confirm with Glendale Development Services.

Rental Income & ROI

Investment Returns

1-Bedroom Rent$1,050-$1,350/month
2-Bedroom Rent$1,350-$1,700/month
Annual Rental Income (est.)$14,400/year
Payback Period (est.)12.7 years
Short-Term RentalYes, 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
Overall ROI Estimate5-8% annual return

A typical ADU in Glendale generates approximately $14,400 per year in rental income based on average 1-bedroom rents. At an average construction cost of $182,500, the estimated payback period is 12.7 years — before accounting for the resale value the ADU adds, which an appraiser determines from comparable sales in Glendale and varies by market (often less than build cost).

Ways to Reduce ADU Costs in Glendale

1. Garage conversions save 40-60% vs new construction since the shell already exists. Average cost in Glendale: $55,000-$135,000.

2. Prefab/modular ADUs offer predictable pricing and faster timelines. Average: $85,000-$200,000.

3. Pre-approved plans — Glendale does not offer a pre-approved/standard ADU plan program yet, so budget for custom architectural plans (typically $3,000-$15,000). See which cities offer pre-approved ADU plans.

4. State grants — California's CalHFA ADU grant (up to $40K) is currently paused; check calhfa.ca.gov/adu for status and your state for active programs.

5. Get multiple bids — ADU contractor pricing varies 20-40% for the same project. We recommend getting at least 3 quotes.

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About this information: This page is an informational summary of publicly available regulations - it is not legal, financial, or professional advice, and it is not a substitute for confirming requirements with your local planning department. Rules change frequently; always verify current requirements before designing, budgeting, or building. Last verified: 2026-09-06. Contractors we introduce are independent businesses - verify license and insurance directly before hiring. Spotted an error? Tell us - we verify against primary sources and correct quickly.

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