Irontown Modular · Authorized Dealer

Modular ADU Homes in Oregon

Make room for family or a rental home. My Cozy Outdoors is your authorized Irontown Modular dealer and direct point of contact. Irontown is the seller of record, with more than 40 years building homes and commercial buildings.

Designed to the International Residential Code; set on a permanent foundation
Delivery and crane set included for 250 miles; then $12.75 per mile per truckload
Free zoning guidance with your quote
10 year limited structural warranty

Get a Quote and Zoning Guidance See the City and County Rules

What counts as an Oregon ADU?

Oregon defines an accessory dwelling unit as an interior, attached or detached residential structure used in connection with or accessory to a single-unit dwelling. Backyard cottage, guest house, mother-in-law suite, granny flat, casita, tiny home and prefab ADU are everyday names. Park models and tiny homes on wheels are different products, outside this guide.

A modular ADU is factory-built to the International Residential Code, the model behind Oregon’s statewide residential code, with engineered, stamped plan sets. A crane sets it on a permanent foundation; it becomes real property. Oregon calls it a prefabricated structure. Irontown’s plans ship as one or two modules.

Where can you put an ADU in Oregon?

Your city or county decides zoning, permits, charges, covenants and code compliance. MCO advises but takes no responsibility; confirm zoning, permits, charges and septic with your city, county or DEQ before ordering.

Start With Local Guidance
This guide is a starting point. MCO helps and advises but takes no responsibility for zoning, permits, impact fees, septic approval or code compliance. Before ordering, you must confirm your parcel, model and use with city or county planning and building offices, and septic approval with the health department. We strongly recommend contacting those offices. MCO can share the code sections it found and suggest questions.

State law sets the starting point

ORS 197A.425 requires cities over 2,500 and counties over 15,000 to allow an ADU per detached house on residentially zoned land inside urban growth boundaries. Outside those boundaries, counties may allow rural residential ADUs under 215.495 only after adopting local rules.

Inside urban growth boundaries, cities over 2,500 and counties over 15,000 must allow an ADU per detached house in detached single-unit zones, subject to reasonable siting and design.
Siting and design rules cannot require owner occupancy of either unit or additional off-street parking. Local governments may impose those requirements for vacation occupancy.
Inside urban growth boundaries, this ADU law sets no size, height, lot-size, fee cap or review time. City or county codes supply local requirements.
A county may allow one 900 sq ft ADU on a rural residential lot of two acres or more, never a vacation rental, only where it adopted that rule (215.495).
A covenant signed since 2021 that allows a house but bars an ADU inside a growth boundary is not enforceable (93.277); older covenants and rural lots differ.
Inside a growth boundary a prefabricated structure may be sited wherever a house may be, on site-built standards (197A.432); the Building Codes Division reviews the factory-built part.

ADU rules inside city limits

These rows show city codes published in September 2026. Every city here exceeds 2,500 people and is bound by state law; the rows print each city’s siting and design rules. Where codes predate the 2019 changes or stay silent, ask how the city applies today’s law.

City	Detached ADU	What the local rule says
Portland	Allowed	Capped at 800 sq ft or 75 percent of the house’s living area (33.205.040.C.1). No owner occupancy. All system development charges waived with a 10 year no short term rental covenant. Phone 503-823-7300.
Salem	Allowed with conditions	Capped at 900 sq ft or 75 percent of the main building’s gross area (SRC 700.007). No short term rental of either unit; system development charges exempt. Phone 503-588-6213.
Eugene	Allowed with conditions	Capped at 800 sq ft or 10 percent of the lot, measured at the exterior walls; 600 in three neighborhoods (EC 9.2751(17)). Ask how the Morada 800 is measured. Phone 541-682-5086.
Bend	Allowed	Capped at 800 sq ft for the first ADU and 500 for a second (BDC 3.6.200(B)). Transportation charge $1,112 plus park $5,309; ask about water and sewer. Phone 541-388-5580.
Redmond	Allowed	Capped at 900 sq ft of gross floor area with a 300 sq ft minimum (Sec. 8.325); building permit only. Ask the city for its system development charges. Phone 541-923-7721.
Medford	Allowed	Capped at 900 sq ft or 75 percent of the house’s habitable floor area (MMC 10.821). Charges cut in half through June 30, 2027 with a no short term rental covenant. Phone 541-774-2380.
Grants Pass	Allowed	Up to two ADUs, each capped at 1,000 sq ft (22.720); the Rabbit 1000 sits 2 sq ft over, so ask how the office measures floor area. Phone 541-450-6060.
Klamath Falls	Allowed	Capped at 50 percent of the house’s gross floor area, garage excluded, with no fixed ceiling (CDO 12.050). The two-story Rabbit 1000 must clear 28 ft; ask. Phone 541-883-4950.
Hood River	Allowed with conditions	Capped at 800 sq ft measured at the exterior walls (HRMC 17.23.010); no short term rental. The Morada 800 measures about 819 sq ft at the walls, so ask. Phone 541-387-5210.
Pendleton	Allowed with conditions	A small dwelling under 900 sq ft, no taller than the house, with its own water and sewer meters (UDC 3.05.2). Ask whether the parking rule still applies. Phone 541-966-0204.
Baker City	Allowed	Up to two ADUs; footprint capped at 1,000 sq ft single story or 700 two story, never larger than the house’s (BCDC 2.2.200.A); 25 ft tall. Phone 541-524-2043.
Ontario	Allowed with conditions	Capped at 900 sq ft gross, smaller than the house (OMC 10A-03-74.1). Ask how factory-built ADUs are filed and what transportation charges apply. Phone 541-881-3224.

ADU rules on unincorporated land

Inside urban growth boundaries, state law binds counties over 15,000: all here except Wallowa, Harney and Lake. Rural residential ADUs require county adoption; farm and forest lots have none. These unincorporated rows identify the planning office to call.

County (unincorporated)	Detached ADU	What the local rule says
Clackamas County Oak Grove, Damascus, Boring, Eagle Creek, Welches, Rhododendron, Government Camp, Mulino, Beavercreek	Allowed with conditions	Capped at 900 sq ft inside a growth boundary, 500 in R-2.5 (ZDO 839.01); rural lots of two acres or more, 900 sq ft (839.04). No owner occupancy. Phone 503-742-4500.
Washington County Aloha, Bethany, Cedar Mill, Raleigh Hills, Garden Home, Cooper Mountain, Rock Creek, Scholls, Gales Creek, Cherry Grove	Allowed with conditions	Capped at 800 sq ft and no taller than the house inside the growth boundary (CDC 430-2); rural lots of two acres or more, 900 sq ft (430-3). Phone 503-846-3470.
Marion County Four Corners, Hayesville, Brooks, Mehama, Marion, Butteville, Elkhorn	Allowed with conditions	Capped at 900 sq ft or 75 percent of the house’s footprint in growth areas (MCC 16.26.100); rural AR lots of two acres or more, 900 sq ft (17.128.020(K)). Phone 503-588-5038.
Lane County Pleasant Hill, Marcola, Elmira, Walterville, Blue River, Dexter, Goshen, Deadwood, Mapleton	Allowed with conditions	Rural lots of two acres or more, capped at 900 sq ft usable floor area by Type I review (LC 16.290(8)); 800 sq ft in the Eugene growth area. Phone 541-682-3577.
Deschutes County Tumalo, Terrebonne, Sunriver, Deschutes River Woods, Three Rivers, Alfalfa, Brothers	Allowed with conditions	Capped at 900 sq ft usable floor area on lots of two acres or more, five in the unsewered south (DCC 18.116.355); not in Tumalo, Terrebonne or Sunriver. Phone 541-388-6560.
Jefferson County Crooked River Ranch, Camp Sherman, Warm Springs	Ask first	A 2025 rural ADU rule (900 sq ft on two acres or more) could not be read; growth-area lots allow one ADU (Section 304). Phone 541-475-4462.
Crook County Powell Butte, Juniper Canyon, Post, Paulina	Allowed with conditions	Capped at 900 sq ft usable floor area on R-5, R-10 and PBR-20 lots of five acres or more, by site plan review (CCC 18.124.140(2)). Phone 541-447-3211.
Jackson County White City, Applegate, Ruch, Sams Valley, Wimer, Trail, Prospect, Lake Creek	Allowed with conditions	Capped at 900 sq ft; rural lots need two acres (LDO 6.4(H)); White City 800 sq ft and 50 percent. Rural units may not be vacation rentals. Phone 541-774-6907.
Josephine County Merlin, Murphy, Williams, Wilderville, Selma, Kerby, O’Brien, Wolf Creek	Ask first	The current rural ADU rule (Code 19.61, amended 2025) could not be read; the older Detached Living Space permit allows 900 sq ft with no oven. Phone 541-474-5421.
Klamath County Keno, Rocky Point, Fort Klamath, Crescent, Gilchrist, Bly, Sprague River, Beatty	Ask first	Inside growth boundaries capped at 800 sq ft and 50 percent of the house (LDC Article 89), with a parking space still printed; rural lots have no ADU rule. Phone 541-883-5121.
Douglas County Green, Melrose, Dixonville, Glide, Tenmile, Camas Valley, Days Creek, Tiller, Umpqua	Allowed with conditions	Capped at 900 sq ft usable floor area on rural lots of two acres or more (LUDO 1.090), 900 or 75 percent of the house in growth areas. Phone 541-440-4289.
Coos County Bunker Hill, Charleston, Barview, Allegany, Greenacres, Hauser, Remote, Sitkum	Allowed with conditions	Capped at 900 sq ft on RR lots of two acres or more, by Type I review (CCZLDO 4.3.210(27)); 800 sq ft or 75 percent in growth areas. Phone 541-396-7770.
Lincoln County Otis, Rose Lodge, Neotsu, Gleneden Beach, Lincoln Beach, Seal Rock, Tidewater, Logsden, Otter Rock	Allowed with conditions	Only inside a growth boundary: city standards, or 800 sq ft or 75 percent of the house (LCC 1.1540). Rural lots outside a growth boundary have no ADU rule. Phone 541-265-4192.
Tillamook County Neskowin, Pacific City, Cloverdale, Hebo, Netarts, Oceanside, Cape Meares, Barview, Neahkahnie	Allowed with conditions	Capped at 900 sq ft on RR lots of two acres or more (TCLUO 3.010(5)), 24 ft on ocean or bay frontage; 800 or 75 percent in communities (5.110). Phone 503-842-3408.
Clatsop County Arch Cape, Svensen, Knappa, Westport, Jewell, Olney, Miles Crossing, Surf Pines	Allowed with conditions	Capped at 900 sq ft gross habitable floor area on lots of two acres or more, no lot minimum in sewered communities (LAWDUC 3.0180(2)); Type I review. Phone 503-325-8611.
Hood River County Odell, Parkdale, Mount Hood, Dee, Pine Grove, Oak Grove	Ask first	No rural ADU rule yet; a draft under 215.495 has been in work since October 2025. Parkdale lots may add one of 900 sq ft usable floor area (12.80). Phone 541-387-6840.
Umatilla County Mission, Rieth, Cayuse, Meacham, Tollgate, Holdman	Ask first	No rural ADU ordinance; RR lots carry one dwelling (UCDC 152.131), and the growth-area code prints no ADU rule, so ask how the county applies the state law. Phone 541-278-6252.
Union County Perry, Hilgard, Medical Springs, Starkey, Telocaset	Allowed with conditions	Capped at 900 sq ft by footprint on lots of two acres or more, after a Planning Commission hearing (UCZPSO 6.03); ask how a two-story unit is measured. Phone 541-963-1014.
Wallowa County Wallowa Lake, Imnaha, Flora, Troy, Minam	Allowed with conditions	Capped at 900 sq ft on R-1 parcels of five acres or more (LDO 17.025(04)), sharing the house’s septic system; no short term rental; administrative review. Phone 541-426-4543, extension 1170.
Baker County Keating, Sparta, Durkee, Pine Valley, Eagle Valley, Sumpter Valley, Bourne	Ask first	The county code prints no ADU (BCZO 510) and no rural ADU ordinance was found; rural lots take one house. Ask how it applies the state law inside growth boundaries. Phone 541-523-8219.
Malheur County Cairo, Arock, Jamieson, Ironside, Juntura, Brogan, Harper	Allowed with conditions	Capped at 900 sq ft usable floor area on R-1 lots of two acres or more (MCC 6-3C-2(E)), sharing the house’s well; no vacation or commercial rental. Phone 541-473-5185.
Harney County Crane, Diamond, Frenchglen, Fields, Riley, Drewsey, Princeton	Ask first	The county has no ADU rule (HCZO 3.090): R-1 lots take one house or one two-family building. With fewer than 15,000 people it is outside the state ADU law. Phone 541-573-6655.
Lake County Christmas Valley, Silver Lake, Summer Lake, Fort Rock, New Pine Creek, Plush, Adel	Ask first	The zoning code (Title 18) could not be read and no ADU rule was found; the county is outside the state ADU law. Ask what the Second Dwelling permit covers. Phone 541-947-6036.

Inside urban growth boundaries the state law binds every city here and every county over 15,000. Counties with a rural ADU rule: Clackamas, Washington, Marion, Lane, Deschutes, Crook, Jackson, Douglas, Coos, Tillamook, Clatsop, Union, Wallowa and Malheur; Jefferson adopted one we could not read. Ask first in Jefferson, Josephine, Klamath, Hood River, Umatilla, Baker, Harney and Lake counties; no city is ask first. Farm and forest lots have no ADU rule.

Ask About My Lot

Choose a plan that fits the local measurements

Oregon’s urban ADU law sets no size cap; cities set their own. Bend caps the first ADU at 800 sq ft. Portland adds a 75 percent house-size limit to its 800 sq ft cap. Rural residential ADUs have a 900 sq ft usable floor area limit. Heights and stories are local too.

Plans up to 793 sq ft fit every 800 and 900 sq ft cap; under 1,000 sq ft the plans up to 989 fit and the Rabbit 1000 is 2 sq ft over, so ask how floor area is measured. Under a 75 percent rule the 793 sq ft Morada 800 needs a 1,058 sq ft house.

Plan	Size	Rooms	Footprint
Mysa 500	497 sq ft	1 bed, 1 bath	14 ft x 36 ft
Cabana 500	497 sq ft	1 bed, 1 bath	14 ft x 36 ft
Sledhaus 500	580 sq ft	1 bed, 1 bath	14 ft x 45 ft with deck
Cabana 700	718 sq ft	2 bed, 1 to 2 bath	14 ft 6 in x 49 ft 6 in (638 sq ft, 44 ft with one bath)
Torrey Flats	696 sq ft	1 bed, 1 bath	15 ft x 48 ft
Morada 800	793 sq ft	1 to 2 bed, 1 to 2 bath	39 ft x 21 ft
Morada 1000	989 sq ft	1 to 2 bed, 1 to 2 bath	43 ft x 24 ft
Rabbit 1000	1,002 sq ft	2 bed, 2 bath	34 ft 8 in x 14 ft 6 in, two story
Walker	1,165 sq ft	2 bed, 2 bath	42 ft x 27 ft

Irontown ADU plans for Oregon

These are Multi-State Designer Series starting prices for Oregon. Irontown’s ADU plans are designed to the International Residential Code. Modern, Balance and Rustic finishes are priced in your quote.

Mysa 500

497 sq ft · 1 bed, 1 bath · from $142,600

497 sq ft; one bedroom, one bath; from $142,600.

See the Mysa 500 plan

Cabana 500

497 sq ft · 1 bed, 1 bath · from $184,400

497 sq ft; one bedroom, one bath; from $184,400.

See the Cabana 500 plan

Sledhaus 500

580 sq ft · 1 bed, 1 bath · from $179,300

580 sq ft; one bedroom, included front deck; from $179,300.

See the Sledhaus 500 plan

Cabana 700

718 sq ft · 2 bed, 1 to 2 bath · from $176,200

638 or 718 sq ft; two bedrooms; from $176,200.

See the Cabana 700 plan

Torrey Flats

696 sq ft · 1 bed, 1 bath · from $193,700

696 sq ft; one bedroom, open kitchen and living room; from $193,700.

See the Torrey Flats plan

Morada 800

793 sq ft · 1 to 2 bed, 1 to 2 bath · from $242,400

793 sq ft; one or two bedrooms; from $242,400.

See the Morada 800 plan

Morada 1000

989 sq ft · 1 to 2 bed, 1 to 2 bath · from $247,700

989 sq ft; one or two bedrooms; from $247,700.

See the Morada 1000 plan

Rabbit 1000

1,002 sq ft · 2 bed, 2 bath · from $239,400

1,002 sq ft; two stories, two bedrooms, two baths; from $239,400.

See the Rabbit 1000 plan

Walker

1,165 sq ft · 2 bed, 2 bath · from $276,800

1,165 sq ft; two bedrooms, two baths; from $276,800.

See the Walker plan

Home price and delivery to Oregon

The Multi-State starting price includes Designer finishes, module delivery, standard crane and set on your foundation for the first 250 miles from Spanish Fork. All Oregon lies beyond that allowance. Approximate extra transportation per load: Ontario $2,500; Bend $6,200; Portland $7,200; Medford $7,900; the coast $8,200 to $9,900.

Nearest townPlanTruckloads (estimated)

Approximate road miles from the factory

Estimated delivery beyond the 250 included miles

Starting price, delivered and set, plus estimated extra miles

Estimate only. Multi-State Designer Series starting price with standard delivery and crane set. Beyond 250 miles the rate is $12.75 per mile per truckload; plans wider than about 15 ft and two-story plans usually ship as two modules, and your quote confirms the count. Foundation, site work, stitch, utilities, permits, fees, engineering, pilot cars and sales tax are not included.

Beyond 250 miles, transportation costs $12.75 per mile per truckload, plus a pilot car if the permit requires it. Single-module plans need one load; bigger plans use two modules on two trucks, stitched on the foundation. The calculator has a truckloads selector. Your written quote confirms loads, pricing, finishes, transportation and tax treatment.

Costs not in the home price

These costs come on top of the home price and are quoted by your general contractor, city and county, not MCO.

Site work, grading and site engineering
Engineered foundation
Utility trenches, connections and meter fees
Septic permits and well work
Module stitching and finishing
Steps, porches, decks and landscaping
Building permits and plan review
System development charges and applicable taxes
Minor transport and set touch-ups

Oregon calls them system development charges, not impact fees: local charges for water, sewer, stormwater, streets and parks. No state ADU exemption applies. Portland and Salem waive them for an ADU (Portland with a no short term rental covenant), Medford halves its ADU rates through June 2027, and Lane County charges none. School construction excise tax applies per sq ft at permitting; some cities add an excise tax. Ask your city or county which charges an ADU pays.

Oregon does not have a general sales or use tax, the Department of Revenue says. Applicable taxes follow the transaction; your written quote shows how tax is handled for your sale. Nightly rentals carry state and local lodging taxes where allowed. A modular ADU on a foundation is real property; the county assessor adds its value to the parcel as of the next January 1.

Living in, renting and owning your ADU

Inside urban growth boundaries, cities cannot require owner occupancy or added parking, except for vacation rentals. Renting the unit as housing is allowed; short-term rules are local. Rural ADUs cannot be vacation rentals. Covenants signed since 2021 barring an ADU inside a growth boundary are unenforceable; older ones differ, so read your declaration.

No row found an owner-occupancy requirement. Salem bars short term rentals anywhere on an ADU lot; Hood River bars them in the ADU. Marion County prints 30 day urban and 45 day rural rental minimums. Malheur County bars vacation and commercial rentals. Rural ADU counties prohibit vacation occupancy.

Plans, permits and inspections

Stamped plans go to your local building department for permitting. Your plan approval and inspection path are confirmed with Irontown during feasibility review.

Most cities use building permits; some require land use review. Rural ADUs need county land use decisions, which take longer.
Irontown supplies stamped, engineered plans for your site’s snow, wind, seismic and applicable wildfire requirements under Oregon’s statewide residential code.
Irontown Modular (KEB Homes LLC) is a registered prefabricated structure manufacturer with the Oregon Building Codes Division, which reviews and inspects the factory work.
Statewide design criteria govern; state code requires no home sprinklers. Local fire conditions may apply; wildfire hardening requires local adoption.
Without sewer, the county or DEQ reviews septic first; a household well has exempt-use limits; a water district needs a will-serve letter.

How long does an Oregon modular ADU take?

Irontown’s phases exclude local permit review. Complete simple residential plans have a 10 business day review clock, 15 in Portland, with statutory exceptions. Land use decisions take longer. Local building departments permit and inspect foundations, utilities, set and stitch.

Phase 1 Feasibility Review (1 to 2 weeks). Site, route, budget and schedule review, plus contractor support. The $2,000 fee applies to the final contract price.
Phase 2 Pre-construction Agreement (2 to 3 months). Site visit, detailed planning, site-specific design, finish selections and stamped engineered plans for permitting.
Phase 3 Construction and Delivery (12 to 16 weeks). Irontown builds, ships and sets the modules. Permit, building or site delays can affect the schedule.

Your general contractor’s six on-site steps

Your general contractor coordinates the site work with Irontown. The contractor sets the on-site schedule; these steps have no published durations.

Prepare and coordinate. Evaluate and prepare the site, obtain permits, and coordinate delivery with Irontown.
Build foundation and utilities. Build the engineered foundation and install water, sewer, electrical and gas connections.
Receive and set modules. Prepare access and staging, inspect arriving modules, and coordinate crane placement.
Stitch and finish. Connect modules, weatherproof seams, complete finishes, and connect and test building systems.
Inspect and hand over. Complete inspections, system testing, punch list, walkthrough, and handover of documents and keys.
Support and maintain. Address warranty service and help arrange maintenance schedules when wanted.

You need a general contractor

A general contractor licensed with the Oregon Construction Contractors Board is required for on-site work and prices it separately from the home. Irontown has connections to some general contractors; contact MCO to see whether we can recommend one in your area. Irontown’s feasibility review includes contractor support.

Are you a general contractor building ADUs for clients? Email support@mycozyoutdoors.com to join the MCO contractor network.

Start with your site and a written quote

Share your project. Tell MCO your location, intended use and preferred plan.
Confirm locally. MCO advises but takes no responsibility; confirm zoning, permits, charges and septic with your city, county or DEQ before ordering.
Request your quote. MCO includes free zoning guidance, sharing code sections and suggested questions.
Begin feasibility. Review the site, delivery route, budget, schedule and contractor support with Irontown.
Complete planning. Finalize selections, arrange your contractor and permits, then coordinate construction and delivery with Irontown.

Visit the Spanish Fork factory

Visit Spanish Fork, Utah: about an hour south of Salt Lake City International Airport, with direct Portland flights. Driving takes seven hours from Ontario, eleven from Bend, twelve or more from Portland. Walk finished modules; see finish series.

Schedule a Factory Visit

Common Questions

Does my city have to allow a detached ADU?

Every city listed exceeds 2,500 people. Inside urban growth boundaries, state law requires at least one ADU per detached house on land zoned for detached single-unit dwellings, subject to reasonable local siting and design rules. That requirement does not grant a specific permit.

How big can my ADU be?

Urban limits are local: 800 and 900 sq ft caps are common, sometimes combined with a percentage of the house. Rural ADUs generally have a 900 sq ft usable floor area limit. The office’s measurement method matters.

Can I rent it out, and must I live on the property?

Urban ADUs may be rented as housing without a state-law owner-occupancy requirement. Vacation rentals follow local rules and can carry owner-occupancy conditions. Rural ADUs cannot be vacation rentals; some counties impose additional rental restrictions.

What does an ADU cost all in?

There is no single all-in price. Start with the home quote and extra transportation, then add your contractor’s site-work quote, permits, system development charges, utility costs and applicable taxes. Your location, plan and site determine those amounts.

How long does the process take?

Irontown lists 1 to 2 weeks for feasibility, 2 to 3 months for pre-construction, and 12 to 16 weeks for construction and delivery. Local permitting is additional. Your contractor sets the on-site schedule; delays can affect delivery.

Do I need a general contractor?

Yes. A general contractor licensed with the Oregon Construction Contractors Board handles and separately prices the on-site work. Contact MCO to see whether Irontown’s connections include a contractor for your area. Feasibility review includes contractor support.

Rules were read in September 2026. This summary is not legal advice or approval; rules change and local offices decide their application. MCO takes no responsibility for zoning, permits, impact fees, septic approval or code compliance. You are responsible for confirming these matters with city or county planning and building offices and the health department for septic, and obtaining required permits before ordering. MCO strongly recommends contacting those offices and can share code sections and suggested questions.