Unincorporated Martin County, Minnesota requires a building permit before constructing, moving in, replacing or adding onto a structure1. County zoning also applies outside incorporated municipal limits, while projects inside a city go to that city's clerk21. Martin County Planning and Zoning administers septic permits and inspections34.
At a glance
- Building permit
- Required before covered structural work outside city limits1
- Zoning
- County zoning applies outside incorporated municipal limits2
- Septic permit
- Required; administered by Martin County Planning and Zoning34
- RV living
- Long-term occupancy rule not confirmed; ask Planning and Zoning5
- Tiny home
- County occupancy and minimum-size rules not confirmed; zoning review still applies5
- Owner-builder
- State licensing exemption may apply, but permits are not waived6
- Well permit
- County-specific requirement not confirmed; ask Planning and Zoning who has jurisdiction5
Who to call
Planning & zoning
Martin County Planning and Zoning
County land-use administration, building permits and zoning outside incorporated cities
Martin County Courthouse 201 Lake Avenue Room 104 Fairmont, MN 56031
Septic permits
Martin County Planning and Zoning
County subsurface sewage treatment system permits and inspections
Martin County Courthouse 201 Lake Avenue Room 104 Fairmont, MN 56031
Contact details are copied from each office’s official page and were checked against it on September 27, 2026.
Do you need a building permit in Martin County, Minnesota?
Yes. Before constructing, moving in, replacing or adding onto a structure outside incorporated city limits, Martin County requires a building permit1. For property inside an incorporated city, Martin County directs the applicant to the local city clerk1. Minnesota's State Building Code is the statewide standard for structures it governs, with limited statutory treatment for agricultural buildings and local enforcement rules7. The county-specific code edition, inspection process and certificate-of-occupancy requirement could not be confirmed, so ask Martin County Planning and Zoning what plan review and inspections apply before work begins. Minnesota's owner-builder provision can exempt a qualifying owner from residential contractor licensing when building or improving property to occupy or retain as a rental, but the exemption does not waive permits, inspections or occupancy approval6.
Who handles Martin County building permits, and how do you reach them?
Martin County Planning and Zoning coordinates county land-use administration and maintains the county's subsurface sewage treatment program8. The office is in Room 104 of the Martin County Courthouse, 201 Lake Avenue, Fairmont, MN 56031, and its phone number is 507-238-32428. Start there for a rural building permit, zoning review, septic coordination and the correct application materials. The county permit notice covers work outside incorporated city limits; for a site inside a city, contact that city's clerk instead1. Martin County's building, zoning and septic fee amounts could not be confirmed from the reviewed material, so request the current fee schedule before budgeting. For a new driveway, identify whether the frontage is a county, township, city or state road because Minnesota makes additional highway access subject to regulation and a permit from the responsible road authority9.
Does Martin County have zoning?
Martin County zoning applies to land outside the incorporated limits of municipalities2. That means a rural parcel needs county review even though a mailing address may use the name of a nearby city. Property within an incorporated municipality is governed through the applicable city process rather than the county's unincorporated-area permit notice1. The reviewed county material does not establish numeric setbacks, a minimum lot size, a minimum dwelling size, a lot-coverage limit or a building-height limit. Ask Martin County Planning and Zoning to identify the parcel's district and provide the current dimensional standards before relying on a survey or positioning a house. Minnesota law also allows municipal subdivision ordinances to address lot size, improvements, utilities, floodplains, shorelands and soils, and in some circumstances to extend into nearby unincorporated territory10. A parcel split therefore needs its own jurisdiction check rather than an assumption based only on the county zoning map.
How do septic permits work in Martin County?
Martin County Planning and Zoning permits and inspects septic-system installations, and both county and state rules apply34. Upgrades or replacements must use licensed septic-system designers, inspectors and installers3. Most Minnesota subsurface sewage treatment systems receive construction permits from a county, city or township, while systems designed for flows greater than 10,000 gallons per day require Minnesota Pollution Control Agency permitting1112. Soil feasibility is a major early check in Martin County: only 7.3% of mapped soils are rated without severe limitations for a conventional septic drain field13. That countywide soil statistic does not decide an individual parcel, but it supports arranging site and soil evaluation before finalizing a house location. Off-grid sanitation is not automatically unregulated; Minnesota imposes disposal conditions on primitive dwellings using toilet-waste devices, and local ordinances control first14.
Can you live in an RV or tiny home in Martin County?
Martin County's rules for long-term residential RV occupancy and tiny-home occupancy could not be confirmed. Because county zoning applies outside incorporated municipal limits, ask Martin County Planning and Zoning how the proposed use and structure are classified before buying or moving anything onto a rural parcel2. Do not treat Minnesota's campground law as permission to live in one RV on private land: the statewide licensing rule applies to an area accommodating 5 or more tents or recreational camping vehicles and does not resolve local land-use approval for one parcel15. A tiny home intended as a permanent dwelling still faces the county building-permit rule when it is constructed, moved in, replaced or added onto outside city limits1. New manufactured homes installed for occupancy in Minnesota also require inspection under the federal installation standards program16. Confirm sanitation, setbacks, minimum dwelling size and temporary occupancy directly with Planning and Zoning because those county-specific answers remain unresolved.
Building a home in Martin County: the steps, in order
- Confirm whether the parcel is outside an incorporated city's limits, because that decides whether Martin County or the city clerk starts the permit process1.
- Ask Martin County Planning and Zoning for the parcel's zoning district, dimensional standards, application forms and current fees; county zoning applies outside incorporated municipalities2.
- Apply for the building permit before constructing, moving in, replacing or adding onto the structure1.
- Arrange septic design with licensed professionals and obtain the county septic permit before installation34.
- Ask the office which building inspections and final occupancy approvals apply; construction subject to a Minnesota State Building Code permit must remain accessible for required inspections17.
- Identify the road authority and secure any required driveway-access permit before building the approach9.
- If the building site, fill or a culvert lies in a floodplain, obtain the locally administered floodplain approval before development18.
What should you check before buying land in Martin County?
Confirm the jurisdiction first: county zoning and the county building-permit notice apply outside incorporated municipal limits, while a site inside a city goes through its clerk21. Investigate septic suitability early because only 7.3% of mapped soils are rated without severe limitations for a conventional drain field13. Martin County is overwhelmingly gentle ground, with 99.9% of land at a slope of 15% or less, but a site survey and floodplain check still matter1918. Average annual precipitation is 31.8 inches, and severe drought occurs in about 12.8% of years2021. The nearest city of 100,000 or more is about 106 miles from the county center, so allow for rural travel, materials and contractor scheduling22. The effective property-tax rate is about 1%, with a median annual property-tax bill of about $1,5472324. Before closing, also confirm legal road access, well permitting, utility availability, setbacks and current fees with the responsible offices because county-specific answers for those items could not be confirmed.
Watch-outs
- A Martin County mailing address does not establish permit jurisdiction; county rules apply outside incorporated city limits, while sites inside a city go to that city's clerk1.
- Only 7.3% of mapped county soils are rated without severe limitations for a conventional septic drain field, so investigate onsite wastewater feasibility before fixing the house location13.
- Martin County's long-term RV occupancy, tiny-home minimum size, setbacks and well-permit rules could not be confirmed; ask Planning and Zoning before purchase or placement2.
Sources
- Building Permit Required, quoted and re-checked
- Martin County Land Use, quoted and re-checked
- Martin County Septic Systems, quoted and re-checked
- Martin County Septic Systems, quoted and re-checked
- Martin County Land Use (2026 county census)
- Sec. 326B.805 MN Statutes (Minnesota statewide rule), quoted and re-checked
- 2025 Minnesota Statutes, section 326B.121 (Minnesota statewide rule), quoted and re-checked
- Martin County Planning and Zoning (co.martin.mn.us)
- Minnesota Statutes, section 160.18: Access to roads; approaches (Minnesota statewide rule), quoted and re-checked
- 2025 Minnesota Statutes, Section 462.358: Official Controls: Subdivision Regulation; Dedication (Minnesota statewide rule), quoted and re-checked
- SSTS design (Minnesota statewide rule), quoted and re-checked
- SSTS design (Minnesota statewide rule), quoted and re-checked
- Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
- Minnesota Administrative Rules, part 7080.2450 Maintenance (Minnesota statewide rule), quoted and re-checked
- 2025 Minnesota Statutes, Chapter 327 (Minnesota statewide rule), quoted and re-checked
- Manufactured home information (Minnesota statewide rule), quoted and re-checked
- 1300.0210 INSPECTIONS (Minnesota statewide rule), quoted and re-checked
- Floodplain Regulations (Minnesota statewide rule), quoted and re-checked
- Share of land at 15% slope or less: Bolthole Index county data
- Annual precipitation: Bolthole Index county data
- Share of years in severe drought: Bolthole Index county data
- Distance to the nearest metro area: Bolthole Index county data
- Effective property tax rate: Bolthole Index county data
- Median property tax bill: Bolthole Index county data
Written September 27, 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.