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Anoka County, MN Accessory Structures: ADU Rules (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

ADU rules in Anoka County, MN, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.

Key Facts

Max size
700 square feet of floor area
Max height
15 feet
Lot requirement
Must meet duplex-sized lot area and width
Permit needed
Building permit required, Sec. 3.2.1
Enforcing agency
Public Health and Environmental Services Dept.
Applies to
Unincorporated shoreland lots only

Summary

Anoka County's Shoreland Management Ordinance lets an unincorporated shoreland lot carry one guest cottage in addition to the main house, but only if the lot is at least duplex-sized for its lake or river classification. The cottage is capped at 700 square feet and 15 feet in height and must be screened from the water.

These county ordinances apply to unincorporated areas of Anoka County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

Unless restricted by local building codes, one guest cottage may be allowed on lots meeting or exceeding the duplex lot area and width dimensions presented in Sections 6.2.5 and 6.2.6, provided the following standards are met: A. For lots exceeding the minimum lot dimensions of duplex lots, the guest cottage must be located within an area equal to the smallest duplex-sized lot that could be created including the principal dwelling unit; B. A guest cottage must not cover more than 700 square feet of land surface and must not exceed 15 feet in height; and C. A guest cottage must be located or designed to reduce its visibility as viewed from public waters and adjacent shorelands by vegetation, topography, increased setbacks or color, assuming summer, leaf-on conditions.

Full Breakdown

The ordinance defines a guest cottage as "a structure used as a dwelling unit that may contain sleeping spaces and kitchen and bathroom facilities in addition to those provided in the primary dwelling unit on a lot" (Sec. 5). 6; a lot platted only to single-family dimensions cannot add a second dwelling this way. Where the parcel is larger than the minimum duplex lot, the cottage must sit within an area no bigger than the smallest duplex lot that could be carved out around the existing house.

The structure is capped at 700 square feet of floor area and 15 feet in height, and it must be sited or landscaped, using vegetation, topography, increased setback or color, to reduce how visible it is from public waters and neighboring shorelands under summer, leaf-on conditions. 1 and enforced by the Anoka County Public Health and Environmental Services Department. Because county zoning under Minn. Stat. Ch. 394 reaches only unincorporated territory, this rule applies solely to unincorporated shoreland parcels; Blaine, Coon Rapids, Ham Lake and the county's other cities administer their own shoreland and accessory-dwelling standards.

Violations & Fines

Building or occupying a guest cottage that exceeds 700 square feet or 15 feet in height, or that departs from an issued permit, is a misdemeanor under Sec. 2.2.1 of the Shoreland Management Ordinance, enforced by the Anoka County Public Health and Environmental Services Department. Each day a violation continues can count as a separate offense, and the County Attorney may seek an injunction to stop, correct, or remove noncompliant construction in addition to any criminal penalty.

Frequently Asked Questions

Can I build a guest cottage on my Anoka County shoreland lot?
Only if your lot is at least as large as the duplex-lot minimum for its lake or river classification under Sections 6.2.5 and 6.2.6. If it qualifies, Section 6.3.2 allows one guest cottage up to 700 square feet and 15 feet tall, sited within the smallest duplex-lot area around your existing home and screened from the water and neighboring shorelands.
Does this rule apply inside cities like Blaine or Coon Rapids?
No. Anoka County's shoreland ordinance governs only the unincorporated shoreland areas identified in Section 4.1, and Section 2.1 excludes any shoreland that already has its own local ordinance. Cities within the county, including Blaine, Coon Rapids and Ham Lake, administer their own shoreland and accessory-dwelling rules separately.
What happens if I build a guest cottage bigger than allowed?
It becomes a violation of the Shoreland Management Ordinance. Section 2.2.1 makes any noncompliant construction a misdemeanor, and the Anoka County Public Health and Environmental Services Department can pursue enforcement; the County Attorney may also seek an injunction requiring the structure be corrected or removed.

Sources & Official References

Other rules in Anoka County

All Anoka County rules

How Anoka County compares: Easiest Cities to Build an ADU·Compare Anoka County to another location·View the Minnesota accessory structures overview

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