Arizona's Middle-Housing Law: HB 2721 (2024)

This page is general information for homeowners, not legal advice.

What this law does

HB 2721 opens up single-family lots near the downtowns of Arizona's larger cities to "middle housing" — duplexes, triplexes, fourplexes, and townhomes. If your city has 75,000 or more residents, it must allow those four housing types as a permitted use on every single-family lot within one mile of its central business district, and must reserve room for middle housing in large new developments. The idea is more homes on the land closest to jobs and services, without apartment towers: buildings that still look and feel like houses.

Status

• In force. Signed by the Governor on May 21, 2024 (azleg.gov bill-status record for HB2721, 56th Legislature, 2nd Regular Session); enacted as Laws 2024, chapter 197.
• Took effect on September 14, 2024, the general effective date for laws passed in the 2024 regular session (azleg.gov General Effective Dates table: 56th Legislature, 2nd Regular Session — 09-14-2024).
• Numbering note (a common citation trap): the chaptered session law reads "Title 9, chapter 4, article 6.1, Arizona Revised Statutes, is amended by adding section 9-462.10" — but because other 2024 laws added sections to the same article, the section is compiled in the current Arizona Revised Statutes as A.R.S. § 9-462.13 ("Zoning; development; middle housing; applicability; definitions"). Cite § 9-462.13 for the current law; the enacted text prints 9-462.10.
• City compliance deadline: January 1, 2026 (A.R.S. § 9-462.13(A)).
• Last verified: September 1, 2026 against the compiled text at azleg.gov.

What it actually says

Who must comply, and by when. A municipality with a population of seventy-five thousand persons or more must authorize middle housing by ordinance and incorporate it into its development regulations, zoning regulations, and other official controls on or before January 1, 2026 (A.R.S. § 9-462.13(A)).

The four housing types. Covered cities must allow the development of duplexes, triplexes, fourplexes and townhomes as a permitted use on all lots zoned for single-family residential use within one mile of the municipality's central business district (A.R.S. § 9-462.13(A)). Note: the mandate stops at fourplexes. Some published summaries say the law requires "fiveplexes" — the statute text does not; no five-unit building appears anywhere in it (Laws 2024, ch. 197; A.R.S. § 9-462.13).

"Townhouses" means dwelling units constructed in a row of two or more attached units, each sharing at least one common wall with an adjacent unit and accessed by a separate outdoor entrance (A.R.S. § 9-462.13, definitions). "Middle housing" means buildings compatible in scale, form and character with single-family houses that contain two or more attached, detached, stacked or clustered homes (A.R.S. § 9-462.13, definitions).

The downtown freeze. "Central business district" means an area or series of areas designated by the municipality that are primarily nonindustrial and that attract community activity — including the entire geographic area the municipality had officially designated as its downtown (or equivalent) on September 14, 2024 (A.R.S. § 9-462.13, definitions). That date — the law's effective date — locks in each city's downtown footprint as a baseline, so a city could not shrink its designated downtown after the fact to shrink the one-mile zone.

Large new developments. Covered cities must also allow middle housing on at least twenty percent of any new development of more than ten contiguous acres (A.R.S. § 9-462.13(A)).

What cities may NOT do to middle housing in the covered areas (A.R.S. § 9-462.13(B)):

• Impose requirements that discourage middle housing by making it impracticable (§ 9-462.13(B)).
• Limit middle-housing buildings to fewer than two floors (§ 9-462.13(B)).
• Restrict the floor area ratio below fifty percent (§ 9-462.13(B)).
• Put middle housing through a more restrictive approval process than a single-family home gets (§ 9-462.13(B)).
• Require owner occupancy (§ 9-462.13(B)).
• Require commercial building codes or fire sprinklers (§ 9-462.13(B)).
• Require more than one off-street parking space per unit (§ 9-462.13(B)).

The penalty for missing the deadline. If a covered city fails to adopt the required regulations by January 1, 2026, "middle housing shall be allowed on all lots in the municipality zoned for single-family residential use without any limitations" — citywide, not just within a mile of downtown (A.R.S. § 9-462.13).

Where it applies

• Covered: municipalities with a population of 75,000 or more (A.R.S. § 9-462.13(A)); within those cities, single-family lots within one mile of the central business district, plus the 20% set-aside in new developments over ten contiguous acres (A.R.S. § 9-462.13(A)). By recent Census figures that reaches Arizona's larger cities — Phoenix, Tucson, and Mesa, for example — but see "What's still unsettled" on the exact roster.
• Not covered: cities and towns under 75,000 (A.R.S. § 9-462.13(A)).
• Exempt areas (A.R.S. § 9-462.13(D)): unincorporated areas; areas lacking sufficient urban services; areas without water and sewer service; areas not zoned for residential use; unincorporated areas under interim zoning designations preserving planned-development potential; areas covered under Title 48, chapter 6, article 4; land in the vicinity of a public airport as defined in A.R.S. § 28-8486; and land in the vicinity of a military airport as defined in A.R.S. § 28-8461. (This is our condensed paraphrase of the eight statutory categories; read subsection D for the exact wording.)

What's still unsettled

• How the one mile is measured. The statute says "within one mile of the municipality's central business district" (A.R.S. § 9-462.13(A)) but does not say whether that runs from the district's boundary or some other reference, or how a city must map it.
• Cities without a designated downtown. The definition folds in whatever downtown a city had "officially designated" on September 14, 2024. What the covered area is for a city that had no official downtown designation on that date is not answered in the text we read.
• The exact roster of covered cities. The 75,000 threshold is statutory, but we did not verify from a primary source which cities cross it or which population count governs. Note also a wording quirk: this statute covers cities of "seventy-five thousand persons or more," while the companion ADU statute (A.R.S. § 9-461.18) covers cities of "more than seventy-five thousand" — a city at exactly 75,000 would sit on different sides of the two lines.
• Exemption wording. Our subsection (D) list above is condensed; the airport-related items in particular carry qualifying language (including references to federal compliance) that the reviewer should verify against the statute before publication.
• Litigation and local implementation. We did not verify any pending litigation over this statute, and we did not audit which covered cities have (or have not) adopted complying ordinances since the January 1, 2026 deadline.

Related pages

• Arizona's ADU Law: HB 2720

Verified-answer blog posts (Phoenix MHOD; Starter Homes Act) will be linked after the live Blog collection URL pattern is inspected. Do not invent cost-guide, definition, or permit-process slugs.

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• Chaptered session law (Laws 2024, ch. 197 / HB 2721): https://www.azleg.gov/legtext/56leg/2R/laws/0197.htm
• Current statute, A.R.S. § 9-462.13 (compiled from enacted § 9-462.10): https://www.azleg.gov/ars/9/00462-13.htm
• Bill status, HB 2721 (56th Leg., 2nd Reg. Sess.): https://apps.azleg.gov/api/Bill/?billNumber=HB2721&sessionId=128
• General effective dates (2024 = 09-14-2024): https://www.azleg.gov/general-effective-dates/

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