Building permits, zoning and septic rules in Marion County, Oregon

Unincorporated Marion County requires a building permit to construct, enlarge, alter, move or replace a home or related structure; Oregon’s statewide building code supplies the construction standards^1,16. Listed minor repairs may be exempt, but separate electrical, plumbing or mechanical permits can still apply¹. Qualifying non-dwelling agricultural, forestry and equine buildings need county approval for structural-code exemption¹². Oregon’s owner-builder exemption covers only ceiling heights, room sizes and temperature maintenance: the owner must intend to occupy the home, build entirely personally or with unpaid friends and relatives, and not have used the exemption in the preceding 5 years⁸. A building permit remains required, and an exempt noncompliant structure requires filing the permit with the county clerk for deed recording⁸. Qualifying work on family-owned residential or farm property can separately qualify for contractor-licensing relief⁹.

Marion County Building Inspection handles building permits for unincorporated land at 5155 Silverton Road NE, Salem, OR 97305; call 503-588-5147 or email Building@co.marion.or.us². Inside cities, start the building-permit application at city hall¹⁷. St. Paul issues its building permits, with Marion County performing plan review and inspections; onsite septic permits remain with Marion County Building Inspection except DEQ-reserved systems^5,7. The county’s inspection list for a new single-family home is general and varies with design and materials, and the structural final inspection comes after all work is complete and before occupancy; septic work must be approved before the plumbing or structural final¹⁸. New dwellings and townhouses need a certificate of occupancy or a temporary certificate, and the contractor-information form must be submitted before issuance⁸.

Marion County Planning administers zoning on all unincorporated land: Title 17 applies outside urban growth boundaries and Title 16 within them^3,6. Site plans are reviewed by either Marion County Planning or the city jurisdiction⁴. Keizer, Gervais, Aurora and St. Paul set their own zoning^19,20,21,22. Septic remains with Marion County Building Inspection in Keizer, Aurora and St. Paul, except DEQ-reserved systems; Gervais’s listed septic responsibilities differ, so confirm the application route before filing^5,7.

New AR subdivisions and partitions generally require 2-acre lots; the calculated EFU minimum for a new farm parcel cannot be below 80 acres^13,23. AR houses generally need 20-foot front and rear setbacks and 10-foot side setbacks, with a 35-foot height cap²³. New EFU structures other than farm-exempt buildings need 20 feet front, rear and side, and EFU dwellings have a 35-foot height cap; non-farm dwellings also need 200 feet from abutting farm or timber parcels unless the alternative-site criteria are met¹³.

In unincorporated Marion County’s RS zone, single-family lots generally need 6,000 square feet; qualifying subdivisions approved after the ordinance’s effective date inside the Salem/Keizer urban growth boundary can use 4,000 square feet²⁴. RL requires 4,000 square feet for detached homes and 6,000 for duplexes; RM requires at least 6,000 square feet for multiple-family dwellings and other uses, with additional density and planned-development provisions^25,26.

RS front yards inside the Salem/Keizer boundary are generally 12 feet, or 20 feet for street-facing garages; other urban growth boundaries require 20 feet, and arterial or collector streets can require greater setbacks²⁴. RL generally requires a 12-foot front yard and 5-foot side and rear yards, with larger setbacks for street-facing garages, arterial or collector streets, and specified taller buildings adjoining RS land²⁵. Ordinary structures in RS, RL and RM have a 35-foot height limit, with specified exceptions^24,25,26. Urban subdivision and partition approval also requires compliance with street, utility, drainage and plat requirements²⁷.

Marion County Building Inspection administers onsite septic permits as Oregon DEQ’s contract agent; DEQ supplies the statewide siting, design and installation rules^5,28. Where municipal sewer is unavailable, Oregon requires an onsite septic system, and the lot must have room for an initial and a replacement system²⁸. Community-sewer properties are outside the onsite program, and systems over 2,500 gallons per day go to DEQ⁵. Marion County requires a field visit when an existing system is more than 5 years old or lacks an installation record⁵. The published fee schedule lists $1,029.25 for a first-lot single-family site evaluation and $1,224 for a standard installation permit, including DEQ surcharges²⁹. Only 7.7% of Marion County soils lack severe limitations for conventional drain fields, making site evaluation an early purchase decision³⁰.

Unincorporated Marion County allows one RV space on rural property with a dwelling for no more than 120 days per calendar year, subject to RV standards^10,31. A vacant AR, SA, FT or TC lot can have one RV space under the same cap only if it meets non-resource-dwelling standards¹¹. Wheeled tiny houses generally cannot be permanent dwellings or ADUs^14,15. Campgrounds are a different use: a private FT-zone campground limits any camper to 30 days in a consecutive six-month period and cannot provide individual utility hookups³², and licensed recreation parks are inspected by Marion County Environmental Health³³.

Eligible ADUs outside city limits but within urban growth boundaries need a county building permit, without a land-use application, and only one ADU is allowed per parcel¹⁵. A non-wheeled tiny house must meet all ADU standards¹⁵. An urban manufactured-home ADU must meet ADU standards, be Energy Star certified and bear a HUD certification label¹⁵; rural ADUs are limited to AR land over 2 acres under the zone’s additional conditions¹⁵. Oregon also requires owner consent and approved water, sewage and utility standards for manufactured-dwelling occupancy³⁴. When replacing a lawfully established manufactured dwelling in rural AR, the old dwelling must be removed or demolished within 90 days after occupying the replacement²³.

1. Ask Marion County Planning or the applicable city zoning office to identify the parcel's zone and confirm the dwelling, setbacks and access⁴.
2. Determine whether community sewer is available; otherwise begin Marion County's septic evaluation and septic-permit process^5,35.
3. If the landowner will personally construct, alter or abandon a well, obtain the state landowner permit before work begins³⁶.
4. Obtain a county driveway access permit for covered work in the public right-of-way³⁷.
5. Submit the building-permit application directly to Marion County Public Works for unincorporated land, or start at city hall for property inside a city¹⁷.
6. Schedule building inspections; requirements vary by project design, materials and complexity¹⁸.
7. Receive the certificate of occupancy before occupying a new dwelling or townhouse⁸.

Marion County Planning publishes a fee schedule: administrative review is $770, a conditional use $1450, a variance $1565 and a floodplain or greenway permit $1130³⁸. Ask Marion County Planning to confirm the parcel’s zone, allowed dwelling, setbacks and lot-creation history before assuming acreage makes unincorporated land buildable^3,39. Floodplain or floodway development usually needs a floodplain development permit; a new dwelling or manufactured home generally must use an available site outside the floodplain⁴⁰. A landowner personally constructing, altering or abandoning a well needs a state landowner permit before work³⁶. Covered driveway work in the public right-of-way requires a county access permit with a $50 fee; local fire districts may impose additional driveway requirements^18,37. The effective property-tax rate is about 0.9%, with a median annual bill of about $3,382³⁰.