Montana HOA ADUs & Modifications

Key Findings

• Section 70-17-901 is the operative limit, and it has not changed since 2019. The statute caps how far an association can go when it tightens the use restrictions on an owner who is already there, and it hands that member a recording mechanism to lock the protection in. SB 300 put it on the books in 2019, and no legislature has amended it since. Two attempts to rewrite it — HB 683 in 2023 and SB 431 in 2025 — both died.^1,2,3
• The ADU mandate is municipal, not associational. The Montana Supreme Court upheld the 2023 housing laws in March 2026, but it vacated as an improper advisory opinion the lower court's declaration that those laws cannot displace more-restrictive covenants. That leaves the constitutional question open while the statutory text keeps preserving private covenants.⁴
• No Montana solar, EV, or landscaping mandate binds associations. The only solar statute authorizes voluntary easements, and § 70-1-522 separately protects political signs.^5,6

Details

Section 1: Overview — ADUs and modifications in Montana

Montana runs architectural review on contract, not on statute. The recorded declaration controls most of what a member builds or changes, held in check by a single distinctive statutory limit, and no statewide law overrides an association's covenants on solar devices or accessory dwelling units (ADUs). That limit is Mont. Code Ann. § 70-17-901: it bars a homeowners' association from imposing covenant restrictions more onerous than the ones in force when a member acquired the property, unless that member agrees in writing.¹ Statute identity drives the rest. The Montana Unit Ownership Act (§ 70-23-101 et seq.) governs condominiums, and it is election-based — it reaches a property only when the owners record a declaration submitting it to the Act. Planned communities get no comprehensive statute at all; they run on their covenants, the Montana Nonprofit Corporation Act, and common law, and all of it answers to § 70-17-901.^7,8

For ADUs, the first question is municipal zoning. A 2023 legislative package orders cities to allow ADUs by right, but it binds municipalities, not associations — so inside a community, the declaration still controls whether an ADU goes up.⁹ Solar devices, electric-vehicle (EV) charging, and landscaping fall the same way: the declaration governs, subject to § 70-17-901.⁵ Four federal overlays bind every Montana association no matter what state law says — the Freedom to Display the American Flag Act of 2005, the FCC's OTARD antenna rule, the Fair Housing Act's reasonable-modification duty, and ADA Title III for qualifying common areas.^10,11,12 The sections that follow lay out the framework, the compliance obligations, and the recent action in the legislature and the courts.

Section 2: The legal framework

2A. The Unit Ownership Act, planned communities, and section 70-17-901

Montana has no single HOA statute. The Montana Unit Ownership Act, Mont. Code Ann. § 70-23-101 et seq., governs condominiums, and it is both election-based and condominium-only: the Act reaches a property only when the owners execute, acknowledge, and record a declaration submitting it to the chapter under § 70-23-103.⁷ From there, the declaration and the recorded bylaws supply the association's architectural authority, its use restrictions, and its amendment procedures.

Planned communities sit outside the Act. A planned-community association answers to its recorded declaration of covenants, to the Montana Nonprofit Corporation Act (§ 35-2-113 et seq.) if it incorporated as a nonprofit, and to common law.⁸ Either way, the declaration is the primary source of any power the association has to review a modification and approve or deny it.

One statutory limit cuts across everything: § 70-17-901, which SB 300 enacted in 2019.¹³ It says an association may not enter into, amend, or enforce a covenant, condition, or restriction in a way that "imposes more onerous restrictions on the types of use of a member's real property than those restrictions that existed when the member acquired the member's interest in the real property," unless that member agrees in writing at the time of adoption.¹ A member who claims the benefit can require the association to record an exception with the county clerk and recorder, and the member pays the recording fee. The statute keys on "types of use" — residential, agricultural, or commercial use; the ability to rent for any length of time; and the ability to otherwise develop the property lawfully — and its protection runs from the date the member acquired the property, so a successor who bought after the restriction went in gets nothing from it.¹ Section 70-23-507 carries the same limit into the condominium world, directing that "[a]n association of unit owners shall abide by the provisions of 70-17-901."¹⁴ One 2023 bill, HB 683, would have made covenants expire after five years unless a board reviewed them and voted to renew; it died in the House on the general-bill transmittal deadline, and it is not law.² So a Montana court reviewing an architectural decision starts with the declaration's text and the authority the association draws from it, then measures any new or more-onerous restriction against § 70-17-901.

2B. Solar, signs, and other categories

Montana aims no solar-access mandate at associations. Its only solar-specific statute, § 70-17-301, lets property owners create voluntary written solar easements; it does not bar covenant restrictions on solar energy devices, and it grants no solar right against an association.⁵ So the declaration governs solar installations, checked only by the § 70-17-901 limit on new, more-onerous restrictions.

Montana protects political signs. Section 70-1-522 makes covenant restrictions on signs that advocate for or against a candidate for public office unenforceable, though an association may still set reasonable rules on size, placement, and timing.⁶ We treat that category at the framework level here. On EV charging and landscaping, Montana has no HOA-specific statute; the declaration governs both, subject to § 70-17-901 and the federal overlays. The practical effect is simple: outside the § 70-17-901 limit and the federal overlays, the declaration controls what a member may build, install, or change.

2C. ADUs and federal overlays

The 2023 ADU package works at the municipal level. Senate Bill 528, which Sen. Greg Hertz sponsored and which sits at § 76-2-345, orders every municipality to adopt regulations allowing at least one ADU by right on a lot that already holds a single-family dwelling. An ADU "may not be more than 75% of the gross floor area of the single-family dwelling or 1,000 square feet, whichever is less," and a municipality may not tack on owner-occupancy, matching-design, or extra-parking conditions.⁹ Senate Bill 245, sponsored by Sen. Daniel Zolnikov and codified at § 76-2-304(4), makes larger urban municipalities allow multiple-unit and mixed-use development in commercial zones.¹⁵ Here is the pivot: § 76-2-345 bars a municipality from requiring a restrictive covenant about an ADU, but the same subsection says it "may not be construed to prohibit restrictive covenants concerning accessory dwelling units entered into between private parties."⁹ That sets up a two-layer analysis. The state mandate clears the municipal zoning barrier, but inside an association the declaration still decides whether a member may build an ADU, subject to § 70-17-901. It is what separates Montana from HOA-preemption states like California (Civ. Code § 4751) and Colorado (HB 24-1152), where the ADU right reaches straight into private covenants. The package drew more than two years of litigation; as of this writing it is in effect, and the Montana Supreme Court upheld it in March 2026 (see Section 4).⁴

Four federal overlays bind every Montana association, whatever the declaration or a state statute says. The Freedom to Display the American Flag Act of 2005 (Pub. L. No. 109-243) protects display of the U.S. flag.¹⁰ The FCC's OTARD rule, 47 C.F.R. § 1.4000, bars restrictions that impair the installation, maintenance, or use of covered antennas and satellite dishes within an owner's exclusive-use area.¹¹ The Fair Housing Act, 42 U.S.C. § 3604(f)(3)(A), requires an association to permit reasonable modifications for residents with disabilities, generally at the resident's expense.¹² And ADA Title III reaches common-area facilities that qualify as public accommodations.

Section 3: Compliance obligations created by the framework

A. Architectural review process obligations

The association's authority to review a modification and approve or deny it comes from the declaration — in both planned communities and condominiums — and, for condominiums, from the recorded bylaws adopted under the Unit Ownership Act (§ 70-23-101 et seq.).⁷ No new or amended restriction may run more onerous than what applied when a member acquired the property, unless that member agrees in writing (§ 70-17-901, in both settings).¹ No general Montana HOA statute separately requires written decisions or retained records; those obligations flow from the declaration and from sound governance practice.

B. Modifications the association must permit

Montana imposes no state-level solar, EV, or landscaping mandate on associations; the declaration governs all three. The must-permit obligations that actually bind are federal: display of the U.S. flag under the Freedom to Display the American Flag Act of 2005; covered antennas and dishes under OTARD, 47 C.F.R. § 1.4000; reasonable disability modifications under the Fair Housing Act, 42 U.S.C. § 3604(f)(3)(A); and accessible common-area facilities that qualify as public accommodations under ADA Title III.^10,11,12 Separately, the § 70-17-901 limit constrains new restrictions aimed at existing owners.¹

C. ADU obligations and limits on HOA authority

No Montana statute forces an association to permit an ADU against its own covenants. SB 528 (§ 76-2-345) and SB 245 (§ 76-2-304) bind municipalities, not associations, and § 76-2-345 expressly preserves private ADU covenants.⁹ Inside a community, the declaration governs ADUs, subject to the § 70-17-901 limit on imposing new, more-onerous restrictions on an existing owner.¹

D. Enforcement, dispute resolution, and appeal obligations

Any pre-suit procedure comes from the declaration or, for condominiums, from the Unit Ownership Act. A member who asserts the § 70-17-901 protection can require the association to record an exception with the county clerk and recorder.¹ Montana runs no dedicated HOA regulator and no community-association-manager licensing program, so members and the courts do the enforcing. Disputes start in the Montana District Courts, and appeals go straight to the Montana Supreme Court — the state has no intermediate appellate court.⁴

Section 4: Recent legislative and judicial activity

A. Recent bills

The headline item is still the 2023 ADU package, which lawmakers passed into a severe housing shortage — by one measure, Montana's median home sales price climbed about 90 percent between 2018 and 2023, from $266,473 to $505,419.¹⁶ SB 528, at § 76-2-345, makes municipalities allow one ADU by right on a single-family lot and bars anti-ADU conditions, while it expressly preserves private ADU covenants; SB 245, at § 76-2-304, opened larger urban commercial zones to multiple-unit and mixed-use development.^9,15 Neither one reaches private covenants. The Legislature has also stayed busy on covenant enforcement and duration. HB 325 (2025), sponsored by Rep. Steve Fitzpatrick, amended § 70-17-210 to define who may bring a covenant-enforcement action and to codify covenant abandonment — including a rule that a governing body that "has not met for a period of 15 years is prohibited from taking an enforcement action" against a member whose use is substantially similar to others in the development.¹⁷ Two runs at § 70-17-901 itself came up short: HB 683 (2023), which proposed a five-year covenant expiration, died on the transmittal deadline, and SB 431 (2025), which would have amended § 70-17-901, never passed. The statute stands as adopted in 2019.^2,3

B. Recent appellate rulings

Montana's one headline ruling this cycle settled the 2023 housing laws at the statewide level — and pointedly left the covenant question for another day.

C. Active legislative debates

Covenant duration and enforcement stay live. After HB 325 (2025) codified abandonment rules, and after two failed runs at § 70-17-901 (HB 683 in 2023, SB 431 in 2025), expect more proposals on covenant renewal, enforcement standing, and the durability of architectural restrictions when the Legislature returns in 2027.

Section 5: National positioning and related coverage

Montana belongs to the contract-first states, where the recorded declaration governs modifications, but two features set it apart. First, § 70-17-901 caps how far an association can tighten use restrictions on existing owners without their written consent — a limit most contract-first states simply do not have. Second, the 2023 ADU package preempts municipal zoning while it preserves private covenants, so unlike California (Civ. Code § 4751) and Colorado (HB 24-1152), the Montana ADU right runs only against local government and never reaches into association covenants. For a multi-state operator, the takeaway is concrete: in Montana an association can still restrict ADUs and solar through the declaration, but it cannot impose new, more-onerous restrictions on existing owners without their agreement — and any litigation travels from the District Court straight to the Montana Supreme Court, with no intermediate appellate stop.

HOA Weekly refreshes its Montana ADUs and modifications coverage every quarter as the Legislature and the Montana Supreme Court act, including any further word on the 2023 housing laws and the covenant-duration proposals. The federal frameworks — the Freedom to Display the American Flag Act, OTARD, the Fair Housing Act, and ADA Title III — bind Montana associations no matter what the state framework says.

Recommendations

1. Treat every ADU request as a two-step review. First confirm that municipal zoning allows the ADU — in most cities it now must, by right under § 76-2-345 — then apply the declaration, which independently controls whether the unit belongs inside the community. Do not assume the state mandate overrides the covenants. Threshold that changes this: a future Montana Supreme Court decision that squarely holds the housing laws displace covenants, or a legislative amendment that makes the ADU right binding on associations, would flip this posture.
2. Audit the declaration's amendment and enforcement history against § 70-17-901 before you adopt any new architectural restriction. If a proposed rule runs more onerous than what applied when a current owner acquired, get that owner's written agreement at adoption and record the exception; otherwise it will not hold against that owner. Benchmark: any board action that narrows an existing use — rental limits, ADU bans, new design mandates — should trigger a § 70-17-901 check.
3. Do not deny modifications that fall under the federal overlays. You must permit U.S. flag display, OTARD antennas and dishes in exclusive-use areas, and FHA reasonable modifications, whatever the declaration says — and under OTARD the association carries the burden of proving any restriction valid. Route these requests to counsel instead of running them through a standard architectural denial.
4. Track the 2027 session and § 70-17-210. After HB 325 codified covenant abandonment — including the 15-year non-meeting bar — associations with dormant boards run a real enforcement risk; hold regular meetings, enforce consistently, and document both. Trigger: any new bill that amends § 70-17-901 or § 70-17-210, or a covenant-displacement ruling, warrants a coverage update.

Caveats

• The court vacated as nonjusticiable — it did not decide — the constitutional question of whether the 2023 housing laws can displace more-restrictive private covenants; the statutory text preserves covenants, but a future concrete dispute could still produce a merits ruling.⁴
• We verified SB 431 (2025) as not enacted from the official bill text and from the fact that § 70-17-901 keeps its 2019 title and content; confirm the precise final procedural-action line on the Legislature's bill tracker before republication.³
• We cite the MAID opinion from the full slip-opinion text; confirm it against the official Montana Supreme Court posting once a permanent courts.mt.gov link is available.
• ADU size and permit-fee details reflect § 76-2-345 as codified; individual municipalities may adopt more permissive local rules, and a separate 2025 measure (SB 532) addresses county zoning.

1. Mont. Code Ann. § 70-17-901, Homeowners' association restrictions — real property rights (official Montana Code Annotated, Montana Legislature) ↩
2. HB 683 (2023), Revise laws relating to homeowners' associations (bill text; missed general-bill transmittal deadline, died) (Montana Legislature) ↩
3. SB 431 (2025), Rights of ownership for residential property — limitations on enforcement (bill text amending § 70-17-901; not enacted) (Montana Free Press Capitol Tracker) ↩
4. M.A.I.D. v. State, 2026 MT 53, DA 25-0200 (Mont. Mar. 17, 2026), full slip opinion (Justice Beth Baker) ↩
5. Mont. Code Ann. § 70-17-301, Creation of solar easements (Montana Legislature) ↩
6. Mont. Code Ann. § 70-1-522, restrictions on political election signs unenforceable (summarized with statutory text, Homeowners Protection Bureau) ↩
7. Mont. Code Ann. § 70-23-101 et seq., Unit Ownership Act, incl. § 70-23-103 (submission by declaration required) (Montana Legislature) ↩
8. Montana Nonprofit Corporation Act, Title 35, ch. 2 (§ 35-2-113 et seq.); no omnibus HOA statute (Montana state law reference, RunHOA) ↩
9. Mont. Code Ann. § 76-2-345, Accessory dwelling units — regulations — restrictions (SB 528, 2023; sponsor Sen. G. Hertz) (Montana Legislature) ↩
10. Freedom to Display the American Flag Act of 2005, Pub. L. No. 109-243, 120 Stat. 572 (codified at 4 U.S.C. § 5 note) (govinfo.gov) ↩
11. Over-the-Air Reception Devices (OTARD) Rule, 47 C.F.R. § 1.4000 (Federal Communications Commission) ↩
12. Fair Housing Act, 42 U.S.C. § 3604(f)(3)(A), reasonable modifications (Office of the Law Revision Counsel, uscode.house.gov) ↩
13. Mont. Code Ann. § 70-17-901, history note "En. Sec. 1, Ch. 339, L. 2019" (SB 300, 2019) (Montana Legislature) ↩
14. Mont. Code Ann. § 70-23-507, Restriction on covenants by association of unit owners (Montana Legislature) ↩
15. Mont. Code Ann. § 76-2-304, Criteria and guidelines for zoning regulations (SB 245, 2023; sponsor Sen. D. Zolnikov) (Montana Legislature) ↩
16. Montana's Housing Crisis Fix Survives Constitutional Challenge (median home price data; State Court Report) ↩
17. Mont. Code Ann. § 70-17-210, Covenant enforcement and abandonment (amended by HB 325, 2025; sponsor Rep. S. Fitzpatrick) (Montana Legislature) ↩