Buying a Duplex or Multifamily Property in Billings

Last reviewed October 5, 2026. State law and rent figures are linked to their sources below.

Is buying a duplex or small multifamily property in Billings a good investment in 2026?

A duplex or small multifamily property in Billings can work as an investment, but only when the legal unit count, verified rents, financing and building condition all hold up on that specific property. Montana law now requires Billings to allow duplexes wherever single-family homes are allowed, and starting October 1, 2026, state law caps how much parking a city can require for new homes. Those changes widen what is possible. They do not make any individual deal pencil.

Billings MLS data shows 58 sales of 2 to 4 unit properties in Billings in the 12 months ending October 1, 2026, at a median $419,950. I have worked with investors on several Billings purchases of four units or fewer, and the questions in this guide are the ones those deals turned on.

Key takeaways

• Montana Code Annotated 76-2-304(3), passed as Senate Bill 323 in 2023, requires cities of at least 5,000 residents to allow a duplex as a permitted use wherever a single-family home is permitted. The Montana Supreme Court upheld it in March 2026.
• House Bill 492 (2025) takes effect October 1, 2026. It caps required off-street parking at one space per home, or half a space for homes under 1,200 square feet, with no parking minimums for existing buildings.
• FHA loans on 2 to 4 units require the buyer to live in one of the units. Investors who will not live there use conventional investment loans or DSCR loans.
• A listing labeled "duplex" or "fourplex" does not prove the legal unit count. Confirm it through permits, the assessor's record and zoning before you count rent from every unit.
• Older multifamily buildings need inspections beyond a standard home inspection: sewer scope, electrical service, fire separation between units and shared systems.

What do Montana's zoning changes mean for duplex buyers in Billings?

Montana's duplex law means Billings cannot zone duplexes out of areas that allow single-family homes. Montana Code Annotated 76-2-304(3) requires cities of at least 5,000 residents to allow duplex housing as a permitted use wherever single-family residences are permitted, under rules no more restrictive than those for single-family homes. The law was challenged in court, and the Montana Supreme Court upheld it on March 18, 2026, along with the state's accessory dwelling unit law.

Parking rules change next. House Bill 492, signed in May 2025 and effective October 1, 2026, caps required off-street parking at one space per home and half a space per home under 1,200 square feet. Existing buildings have no parking minimum under the law. On tight lots, parking requirements were often what made a second unit impossible.

The city side of this is covered in my post on Billings zoning changes in 2026, including accessory dwelling units and Planned Development lots, which follow their own rules. Before you rely on any of this for a specific property, confirm the parcel's zoning district with the City of Billings zoning office. A permitted use still needs building permits and code compliance.

How do I confirm a property's legal unit count?

Check four records before you count rent from every unit: the Yellowstone County assessor's record, the City of Billings permit history, the parcel's zoning district and any certificate of occupancy. A basement apartment or converted garage that was never permitted may produce rent today and still cause problems with financing, insurance and resale.

On a multifamily purchase, the first documents I ask the seller for are the rent roll, the current leases and the repair and maintenance records. The rent roll and leases show whether the income on the listing is real and when each lease ends. The maintenance records show what the building has actually cost to keep running, which is often where the listing numbers and the real numbers part ways.

What rents can you underwrite on a Billings duplex or fourplex?

Underwrite each unit against rents for the same bedroom count, condition, parking and utility setup, not against a citywide average. As a reference point, HUD's FY2026 Fair Market Rents for the Billings, MT metro area are $1,132 a month for a one-bedroom, $1,432 for a two-bedroom and $1,983 for a three-bedroom, according to HUD's Fair Market Rent data. Fair Market Rents are a benchmark set for housing assistance programs. They are not a quote for any specific unit.

What changes a unit's rent in practice:

• Bedroom and bathroom count
• Level of renovation
• Off-street parking
• In-unit or shared laundry
• Whether the owner or the tenant pays water, sewer, gas and electricity

Owner-paid utilities are an operating expense that comes straight out of net income, so confirm which utilities are separately metered before you build a rent roll. My Billings rental market guide covers current rent trends and vacancy in more detail.

How does financing work for a duplex or small multifamily in Billings?

Financing depends on two things: how many units the property has and whether you will live in one of them. Properties with 2 to 4 units can use residential loans. Five or more units move into commercial lending.

Down payment, reserve and rental-income rules vary by lender and program, so get the terms in writing from your lender before you set a purchase price. The CFPB's homebuying resources explain how lenders evaluate income and reserves.

A note on pricing: citywide medians do not value a duplex. The Billings median sale price was $385,000 for residential sales from October 2025 through September 2026, according to Billings MLS data in my Billings housing market report, but a 2 to 4 unit property should be valued against recent 2 to 4 unit sales, its actual leases and its verified expenses.

What do 2 to 4 unit properties sell for in Billings?

Billings 2 to 4 unit properties sold for a median $419,950 over the 12 months ending October 1, 2026, at a median 98.0% of original list price and a median 40 days on market, according to Billings MLS data for 58 closed sales with a Billings address.

Source: Billings MLS, closed sales of 2 to 4 unit properties with a Billings address, October 13, 2025 through October 1, 2026, compiled by Gene Hauck. The triplex and two-houses counts are small, so treat those medians as rough.

Three things stand out in that data:

• Duplexes move; fourplexes sit. Duplexes sold in a median 20 days at 99.9% of original list price. Fourplexes took a median 175 days and sold at a median 84.6% of original list price, so fourplex buyers have had far more room to negotiate.
• Creative financing is common. 21% of these sales closed on a contract for deed or seller financing, compared with 38% on conventional loans, 16% cash, 9% through a 1031 exchange and 9% FHA.
• The stock is old. The median year built was 1965, and 45% were built before 1960, which is why the inspection list below matters.

What should you inspect in an older Billings multifamily building?

Treat the inspection on an older multifamily building as a second round of underwriting. Beyond a standard inspection, cover these items:

• Sewer line. Get a camera scope. Several units put daily load on one line that may be decades old.
• Electrical service and panels. Confirm panel age, amperage and whether each unit has its own service.
• Foundation and structure. Look for settling, cracked masonry and doors or windows out of square. Freeze-thaw cycles in Billings winters add stress over time.
• Roof. Get the age and remaining life in writing. A roof on a fourplex is a large capital expense.
• Fire separation between units. This is a life-safety and lender issue, and unpermitted conversions often lack it.
• Heating and water heaters. Know which systems are shared and who maintains them.
• Utility metering. Document which utilities are separately metered for each unit.
• Egress and handrails. Deficiencies affect safety, insurance, financing and your ability to lease.

Shared items deserve their own line in your due diligence: laundry equipment ownership, common-area lighting, exterior maintenance and whether parking meets the current code.

How does a duplex compare with other Billings investment strategies?

A duplex is one of several ways to invest in Billings. If you are deciding between strategies, my post on flip or rental in Billings walks through how to screen a property for each, and the Billings real estate investing page covers rents, financing and the areas investors look at most. Property taxes also change the math: a qualifying long-term rental gets the same tiered rates as a primary residence, as explained in my guide to Billings property taxes.

Frequently asked questions

How much does a duplex cost in Billings?

Billings duplexes sold for a median $424,700 across 30 closed sales in the 12 months ending October 1, 2026, with a median 20 days on market, according to Billings MLS data. Across all 2 to 4 unit properties, the Billings median was $419,950 on 58 sales.

Can I convert a single-family home into a duplex in Billings?

Possibly. Montana Code Annotated 76-2-304(3) requires Billings to allow duplexes as a permitted use wherever single-family homes are permitted, and the Montana Supreme Court upheld that law in March 2026. A conversion still needs City of Billings building permits and must meet building and fire codes, so confirm the parcel's zoning district and permit requirements with the city first.

How do I verify that a Billings property is a legal duplex or fourplex?

Compare the Yellowstone County assessor's record, the City of Billings permit history, the parcel's zoning district and any certificate of occupancy. If a unit was created without permits, it can cause financing, insurance and resale problems no matter what rent it collects today.

What rent can a duplex unit get in Billings?

It depends on the unit. HUD's FY2026 Fair Market Rents for the Billings, MT metro area are $1,132 a month for a one-bedroom, $1,432 for a two-bedroom and $1,983 for a three-bedroom, but actual rent depends on condition, parking, laundry and who pays utilities. Use rents from comparable units when you underwrite a specific property.

Can I use an FHA loan to buy a duplex in Billings as an investment?

Not as a pure investment. FHA loans on 2 to 4 unit properties require you to live in one of the units as your primary residence. Investors who will not live on site typically use a conventional investment loan or a DSCR loan, which usually requires a larger down payment.

What changes for Billings parking requirements on October 1, 2026?

Under House Bill 492 (2025), Montana cities that use zoning may require no more than one off-street parking space per home, or half a space for homes under 1,200 square feet, starting October 1, 2026. Existing buildings have no parking minimum under the law.

If you want to run the numbers on a specific Billings duplex or fourplex, call or text me at 406-861-4844.

Gene Hauck is a Real Estate Broker and REALTOR® with The Morales Group at Engel & Völkers Billings, 1921 1st Ave N, Billings, MT 59101. He works with buyers relocating to Billings, real estate investors and Billings-area homeowners selling their homes. Call or text 406-861-4844.

This article is general information, not legal, tax or lending advice. Confirm zoning, permits and loan terms with the City of Billings, your attorney and your lender. Equal Housing Opportunity.