ADU rules in Marion County, OR — also called accessory dwelling unit regulations or granny flat ordinances — cover setbacks, owner-occupancy, parking, and permit requirements.
Oregon law requires Marion County and its cities to allow at least one accessory dwelling unit (ADU) for each detached single-family home in urban-growth-boundary residential zones, subject only to reasonable siting and design rules. Owner-occupancy and extra off-street parking cannot be required.
Under House Bill 2001 (2019), codified at ORS 197.312(5), a county with a population greater than 15,000, like Marion County (about 347,000), must allow one ADU per detached single-family dwelling on land zoned for such dwellings within an urban growth boundary. An ADU can be an interior, attached, or detached unit. Salem, Keizer, and Woodburn implement this in their development codes. Critically, local regulations relating to siting and design cannot include owner-occupancy requirements or a demand for additional off-street parking. In the unincorporated rural county, ADU siting also follows the Marion County Rural Zoning Code, including the 100-foot accessory-building setback near farm or forest land. Confirm zone and UGB status with the Marion County or your city planning office.
Building an ADU without the required land-use and building permits is a code violation enforced by the county or city planning and building department, with stop-work orders, permit-after-the-fact requirements, or removal. Standards vary by jurisdiction.
Other ordinances people look up for this city. Green dot = verified primary-source excerpt.
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Marion County has no ordinance banning backyard composting, and no permit is needed for a home compost pile. It must not become a nuisance, attract rodents o...
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Marion County has no ordinance banning or specifically regulating residential artificial turf. Installation on private property is generally allowed. Check d...
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Marion County does not require any particular plants and does not ban native or xeric landscaping. Ornamental landscape grasses that are not a fire or traffi...
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Oregon law lets you collect rain and snowmelt from a rooftop or other artificial impervious surface without a water right. Marion County has no ordinance ban...
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Marion County itself sets no residential watering schedule. In Salem, the Public Works Director may curtail water use whenever a supply shortage or emergency...
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All of Marion County outside city limits is a weed control district. Landowners must destroy designated noxious weeds and stop them from seeding. Inside the ...
See how Marion County's adu rules rules stack up against other locations.
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