Bolthole Index

Marion County, Oregon

Zoning, building permits and septic rules in Jefferson, Oregon

The City of Jefferson, in Marion County, Oregon, adopts its own zoning through its Title 12 Development Code1, and its city planner is the contact for building permits and zoning2. Single-family lots in residential districts need at least 6,000 square feet3. Septic permits for Marion County are issued by Marion County Building Inspection as a state DEQ contract agent4; we could not confirm how that applies inside city limits.

At a glance

Zoning
City of Jefferson Title 12 Development Code, standards by district (R-1, R-2, R-3, MU)1
Building permits
Handled through the city planner; the city's own building code text was not confirmed2
Minimum lot size
6,000 sq ft for single-family and duplex lots in residential districts3
Front setback
15 ft, with 20 ft in front of any garage5
Septic
Marion County Building Inspection issues septic permits as a DEQ contract agent4
RV living
Code addresses RV parks; rules for an RV on a private lot not confirmed6
Wells
State landowner well permit required before work begins7

Who to call

Building permits

City of Jefferson Planning (building permits and zoning)

Building permits and zoning inside Jefferson city limits

541.327.2768

planner@jeffersonoregon.org

150 N. 2nd St. / PO Box 83, Jefferson, OR 97352

Septic permits

Marion County Building Inspection - Onsite Sewage Disposal Program

Septic site evaluations, installation permits, alterations and repairs in Marion County as DEQ's contract agent

503-588-5147

Contact details are copied from each office’s official page and were checked against it on October 14, 2026.

Off-grid gear

Going off-grid in Jefferson means bringing your own water and power. The kit we’d start with:

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Does Jefferson, Oregon have zoning, and what does it mean for lot size and setbacks?

Yes. The City of Jefferson sets residential standards by district under its Title 12 Development Code1. The residential districts named in the code are R-1, R-2 and R-3, plus a mixed-use district8.

Inside the residential districts, a single-family dwelling or a duplex needs a lot of at least 6,000 square feet, a three-family dwelling needs 10,000, and a four-family dwelling needs 12,0003. The minimum front yard is 15 feet, with 20 feet kept clear in front of any garage5.

We did not review Jefferson's agricultural district or its full district map, so confirm the district and standards for a specific lot with the city planner2.

Do you need a building permit in Jefferson, and who issues it?

The City of Jefferson's contact page lists a city planning contact for building permits and zoning, so start there for any project inside city limits2. We could not confirm the text of the city's building code or its permit fees, so ask the planner what a given project needs before you start work.

Marion County's own building-permit rules describe unincorporated land; see the Marion County page for what applies outside Jefferson's limits9.

How do septic permits work in Jefferson?

Septic permits across Marion County come from Marion County Building Inspection, which acts as a contract agent of the Oregon Department of Environmental Quality4. Properties served by a community sewer system are excepted from that process4.

If a lot is inside a city limit, applicants need a written statement from the municipality with sewer authority along with the septic application10. Where local rules set no distance, a construction-installation permit looks to whether the nearest sewer connection point is within 300 feet10.

We could not confirm whether a given lot in Jefferson is on city sewer; ask the city and Marion County Building Inspection11.

Can you live in an RV or tiny home in Jefferson?

Jefferson's code addresses RV parks, which must provide at least 700 square feet for each RV space6. Rules for living in an RV outside a park were not found, so call the city planner before parking an RV on a lot you plan to occupy2.

We could not confirm Jefferson's rule for tiny homes. Marion County's prohibition on wheeled tiny houses as permanent dwellings applies to unincorporated land, not city limits12.

What stays with Marion County and the state?

Septic permits for Jefferson addresses go through Marion County Building Inspection4. Water-supply wells fall under a state landowner permit, which requires a $10,000 bond and a $550 fee before work starts7.

The county's rules for unincorporated land, including its zoning codes, do not apply inside Jefferson13. Land outside city limits is covered on the Marion County page.

Watch-outs

  • We could not confirm Jefferson's building code, permit fees or inspection process; ask the city planner before you buy or build2.
  • Jefferson's agricultural district and full zoning map were not reviewed, so confirm a lot's district with the city before relying on the 6,000-square-foot residential minimum3.
  • Whether a particular lot can use a septic system or must connect to city sewer was not confirmed; a written statement from the sewer authority is needed inside city limits10.

Sources

  1. Chapter 12.20 Residential (R) District Standards - City of Jefferson, OR (Jefferson), quoted and re-checked
  2. City of Jefferson Planning (building permits and zoning) (jeffersonoregon.org)
  3. Chapter 12.20 Residential (R) District Standards - City of Jefferson, OR (Jefferson), quoted and re-checked
  4. Onsite Sewage Disposal Program (Septic) — Background, quoted and re-checked
  5. Chapter 12.20 Residential (R) District Standards - City of Jefferson, OR (Jefferson), quoted and re-checked
  6. Chapter 12.60 Manufactured and Mobilehomes - City of Jefferson, OR (Jefferson), quoted and re-checked
  7. Landowner Constructed Wells, quoted and re-checked
  8. Chapter 12.60 Manufactured and Mobilehomes - City of Jefferson, OR (Jefferson), quoted and re-checked
  9. Building Inspection, quoted and re-checked
  10. Onsite Wastewater (Septic) Rules Update, quoted and re-checked
  11. Marion County Building Inspection - Onsite Sewage Disposal Program (co.marion.or.us)
  12. co.marion.or.us, quoted and re-checked
  13. Zone Codes, Comprehensive Plan and Other Regulations, quoted and re-checked

Written October 14, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

Answers from the rulebook for Jefferson

Jefferson’s own rules

  • Local zoningPresent (with conditions)

    Land inside Jefferson city limits; the city's Title 12 Development Code sets residential district standards

    • Standards are by district (R-1, R-2, R-3, MU, etc.)
    “residential uses shall be in conformance with the provisions outlined in this chapter.”
  • Zoning districtsPartial

    Zoning districts inside Jefferson city (R-1, R-2, R-3, MU named in code)

    • Full district list and map not reviewed
    “manufactured/mobilehome parks and expansions thereof are permitted in the r-1, r-2 and r-3 districts”
  • Minimum lot sizeSpecified

    Residential districts inside Jefferson city (single-family and duplex lots)

    • Three-family 10,000 sq ft; four-family 12,000 sq ft; larger multifamily by per-unit formula
    • Ord. 731, 5/23/2024 amended section
    • Agricultural district not reviewed

    minimum lot area single-family: >= 6000 sq ft · minimum average lot width single-family: >= 60 ft (70 ft at building line on cul-de-sac bulb) · minimum lot depth: >= 80 ft

    “a. single-family dwellings: 6,000 square feet; b. duplex dwellings: 6,000 square feet; c. three-family dwellings: 10,000 square feet; d. four-family dwellings: 12,000 square feet;”
  • SetbacksSpecified

    Residential zone inside Jefferson city

    • Corner lots have two front yards
    • 20 ft in front of any garage
    • Side: any point of a building over 15 ft high must be set back at least one-third of its height

    front yard: >= 15 ft (20 ft in front of garage) · rear yard dwelling: >= 20 ft (5 ft for accessory building) · side yard: >= 5 ft (one-third height above 15 ft)

    “the minimum front yard setback in a residential zone shall be 15 feet from the property line provided that a minimum of 20 feet shall be maintained in front of any garage”
  • Living in an RVLimited

    Recreation vehicles inside Jefferson city; code addresses RV parks

    • RV parks built to state standards
    • 700 sq ft minimum per space
    • Rules for RVs outside parks not found

    stay limit for RV not occupied as dwelling or not connected: <= 60 days per 90 days

    “the space provided for each rv shall be not less than 700 square feet”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Jefferson or Marion County directly.

  • Building permit — Building permits inside Jefferson city
  • Owner-builder exemption — Owner-builder exemption inside Jefferson city
  • Building code adopted — Building code inside Jefferson city
  • Inspections — Building inspection inside Jefferson city
  • Certificate of occupancy — Certificate of occupancy inside Jefferson city
19 more unanswered
  • Minimum dwelling size
  • Lot coverage
  • Building height
  • Camping on your land
  • Tiny homes
  • Accessory dwellings
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Off-grid sanitation
  • Well permit
  • Mandatory utility hookup
  • Agricultural exemption
  • Subdividing land
  • Driveway access
  • Building in a floodplain
  • Short-term rentals
  • Permit fees
  • Permit process

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Unanswered questions are usually a sign that Jefferson publishes no rule on the point, not that none exists. Marion County’s page lists the county offices to call.

← All of Marion County: county rules, score and offices