Washington County, MN Accessory Structures: Shed & Carport Rules (2026)
Shed permit rules in Washington County, MN, also referred to as storage shed, backyard shed, or accessory building regulations, set size limits, setbacks, and when a building permit is required.
Key Facts
- Permit
- Building permit required for nearly all accessory structures
- Under 1 acre (overlay)
- 720 sq ft cap
- 5.01-20 acres (overlay)
- 2,500 sq ft cap
- Over 20.01 acres (overlay)
- Unlimited if agricultural
- Bonus shed allowance
- One 120 sq ft shed exempt from count
- Size table applies
- Shoreland & St. Croix Overlay Districts only
Summary
Washington County requires a building permit for nearly every accessory building, and caps shed size by lot acreage inside its Shoreland and St. Croix River Overlay Districts. A parcel under 1 acre is capped at 720 square feet of accessory structures; the limit rises with acreage to unlimited square footage past 20 acres for agricultural buildings.
1.2 Accessory Structures (1) Required Permits. A building permit is required for all accessory structures except agricultural buildings on a farm as defined in Minnesota Statute 16B.61. A Certificate of Compliance is required for all agricultural buildings and accessory structures in the Shoreland Management Overlay District and the St. Croix River Management Overlay District. ... (3) The following standards apply within the Shoreland Management Overlay District and the St. Croix River Management Overlay District: ... (B) The permitted sizes of accessory structures are as follows: Parcels less than 1 acre 720 sq. ft.; 1 acre – 2.49 acres 1,000 sq. ft.; 2.5 – 5 acres 2,000 sq. ft.; 5.01 acres – 20 acres 2,500 sq. ft.; 20.01+ acres *unlimited (*provided they are agricultural structures).
Full Breakdown
Chapter Two Section 1.2(1) of the Washington County Development Code requires a building permit for all accessory structures except agricultural buildings on a farm as defined in Minnesota Statute 16B.61, and requires a Certificate of Compliance for agricultural buildings and accessory structures located in the Shoreland Management Overlay District or the St. Croix River Management Overlay District. Inside those two overlay districts, Section 1.2(3)(B) caps total accessory structure square footage by lot size: parcels under 1 acre are limited to 720 square feet, 1 to 2.49 acres to 1,000 square feet, 2.5 to 5 acres to 2,000 square feet, 5.01 to 20 acres to 2,500 square feet, and parcels over 20.01 acres carry no size limit provided the structures are agricultural.
Section 1.2(3)(A) also limits the count of accessory structures on smaller overlay parcels: one on lots under 2.5 acres, two on lots between 2.5 and 20 acres, plus an added allowance for one shed of 120 square feet or less regardless of that count limit. Accessory structures cannot be built closer to the road right-of-way than the principal structure under Section 1.2(2)(C) unless the local unit of government approves the location and all setbacks are met. Outside the overlay districts, the Section 1.2(1) permit requirement still applies, but the acreage-based size table does not.
Violations & Fines
Building or expanding an accessory structure without the required permit, or exceeding the overlay district's size table, is a Development Code violation. Chapter One Section 15.1 makes any violation a misdemeanor carrying a fine, imprisonment, or both, plus the cost of prosecution, and the Zoning Administrator can withhold the Certificate of Compliance needed to legalize the structure.
Frequently Asked Questions
Do I need a permit for a small storage shed?
How big can my shed be on a 3-acre lot?
Does the size table apply everywhere in the county?
Can I build a shed before my house?
Sources & Official References
Other rules in Washington County
Compare Washington County to another location·View the Minnesota accessory structures overview
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