Residential drafting in Phoenix, Arizona
Phoenix has more older housing than any other city in the metro, and it is not one older housing type. The city lists thirty six residential historic districts, from prewar neighborhoods like Garfield and Coronado through postwar subdivisions built out in the 1940s and 1950s. Campus Vista is typical of the postwar core: single story masonry ranch houses, mostly brick or painted block, on lots around 70 by 125 feet with alleys behind most streets and side yards of seven to ten feet.
Those houses have had seventy years to change. Garages and carports get enclosed, windows get replaced, and stucco goes on over the original masonry, so the exterior is not reliable evidence of what the wall actually is. Permit history helps less than it should: Phoenix permits are only searchable online from 1995 forward, and anything earlier takes a records request. Drawings for an older Phoenix house start with field measurement.
The city also holds patterns most of the metro does not. Along North Central, single family parcels run from a third of an acre to nearly three acres. On the mountain edges, slopes bring hillside review and a different site drawing altogether. A Phoenix address, by itself, says almost nothing about the house.
The drafting work here is mostly about establishing what exists. Once the real wall construction, roof framing, and lot conditions are on paper, the addition or casita can be designed against facts instead of assumptions.
ADU standards
Setback, size, and parking rules for an accessory dwelling unit in Phoenix.
| Maximum size | 75% of the primary dwelling. Capped at 1,000 sq ft on lots of 10,000 sq ft or less; on larger lots, the lesser of 3,000 sq ft or 10% of net lot area (706.A.8) |
|---|---|
| Side and rear setback | 3 ft interior side and rear; 5 ft street side; 0 ft where adjacent to a fully dedicated alley (706.A.4) |
| Height | 15 ft for a detached unit placed in a required side or rear yard, more by use permit. Otherwise the primary dwelling height standard applies (706.A.4 and 307) |
| How many | Two ADUs per lot with one detached single family dwelling. A third on lots of 43,560 sq ft or more when at least one unit is restricted affordable (608.E.2) |
| Rented separately | Not specified |
| Parking | Not specified |
| Lot coverage | The lot coverage standard of the underlying district applies (706.A.7) |
| Front placement | A detached unit generally cannot sit between the house and the front property line without a use permit (706.A.5 and 307) |
Phoenix is the most permissive large city in the metro on size. On a lot over 10,000 square feet the ceiling rises to the lesser of 3,000 square feet or 10 percent of net lot area (706.A.8), triple the state floor.
The 3 ft side and rear setback (706.A.4) is tighter than the 5 ft most valley cities use, and drops to 0 ft against a fully dedicated alley. On a tight lot those two feet decide the floor plan.
For short term rental, the city requires the owner to live on the property when a unit approved on or after September 14, 2024 (A.R.S. 9-500.39(B)(9)) is operated that way, administered through its short term rental program.
Phoenix lists four preapproved ADU plans, but all four are marked in review and none is currently available.
Planning office: Phoenix Planning and Development
Sources: Phoenix Zoning Ordinance 608.E.2 and 706.A. Ordinance G-7317, adopted November 2024. A.R.S. 9-461.18. A.R.S. 9-500.39. Last checked August 2026.
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