ADU Pass
Northern Mariana Islands
The Northern Mariana Islands' housing stock faces pressure from limited land and tropical weather conditions. Accessory dwelling units offer property owners a way to expand capacity on existing residential lots. ADU Pass helps CNMI residents navigate the permitting requirements for secondary structures.
Map
State ADU details
State financing programs
CNMI's primary housing finance vehicle is the Northern Marianas Housing Corporation (NMHC), a CNMI public corporation established under 2 CMC ch. 4 (admin code Title 100). NMHC is the CNMI's HUD HOME Investment Partnerships passthrough and operates loan programs that can finance ADU-equivalent construction on residential parcels. Specifically, NMHC offers a Rehabilitation Loan ($1,000–$40,000, 0–3% fixed, up to 20-year term) for home rehab including unit creation; and a New Construction or Home Purchase Loan (up to $57,000, 2–5% fixed, 30-year term). For Article XII land tenure (i.e., parcels held under homestead permit rather than fee simple), NMHC offers ACCOMMODATION MORTGAGES executed jointly with the CNMI Department of Public Lands, with the loan retained until the homestead permit holder obtains a deed — this mechanism allows financing on land that cannot yet be conventionally collateralized. NMHC also administers CDBG-DR funding for typhoon-recovery rebuilds (post-Yutu 2018, post-Mawar/Bolaven cycle) which has produced ADU-adjacent reconstruction work.
State insurance regimes
CNMI's insurance regulator is the Office of the Insurance Commissioner within the CNMI Department of Commerce. The Insurance Commissioner is a NAIC member state regulator and licenses admitted carriers writing Disability, General Casualty, Marine, Property, Surety, and Vehicle insurance lines. CNMI is acutely typhoon-exposed (Super Typhoon Yutu Oct 2018 caused catastrophic damage on Saipan and Tinian; Super Typhoon Mangkhut Sep 2018 hit Rota; multiple subsequent storms have stressed the residential insurance market). There is NO commonwealth-run FAIR Plan, NO wind pool, NO state-of-last-resort property insurer. Property insurance is written entirely by admitted carriers and surplus-lines markets; capacity has tightened materially after each major storm. CNMI participates in FEMA NFIP for flood; coastal-flood and storm-surge exposure is significant on all inhabited islands. ADUs are covered as 'other structures' on the parcel's homeowner policy or via dwelling-fire endorsement when rented; underwriting reflects the territory-wide typhoon premium.
Known state issues (3)
- other (since 1976-01-09) — ADU economics in CNMI bifurcate sharply by Marianas-descent status. For Marianas-descent owners on fee-simple or homestead-permit land, conventional ADU pro-formas work (subject to NMHC financing). For non-Marianas-descent investors, the 55-year leasehold cap and the inability to obtain freehold collateralization fundamentally change the underwriting math; most mainland ADU pro-forma templates do not translate.
- other (since 2018-10-25) — ADU project pro-formas in CNMI must include a typhoon-construction premium (hurricane clips, impact-rated openings, reinforced roof structure) and an insurance line item that may be 2–4× comparable CONUS exposure. Building-code compliance is effectively an insurability prerequisite, not just a permit requirement.
- policy-review (since 2013-07-15) — ADU practitioners working across islands must verify each island's permitting framework independently. The Saipan Zoning Office cannot speak for Tinian or Rota permitting.
Federal (United States) — ADU-relevant rules and programs
Federal ADU law
The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.
Federal financing programs
Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.
Federal tax credits
There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.
Federal housing programs
HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.