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Boone County, MO Accessory Structures: Garage Conversions (2026)

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

Garage conversion rules in Boone County, MO, sometimes called garage-to-ADU or accessory living unit conversions, govern permits, ceiling height, egress, and parking replacement.

Key Facts

General rule
no dwelling use in accessory buildings
Only exception
permitted accessory dwelling unit
ADU size cap
75% of house or 1,500 sq ft
Section
Zoning Ordinance § 7.1.5.4

Summary

Boone County zoning bans converting a garage or other accessory building into living space, with the only exception being an approved accessory dwelling unit.

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

Accessory buildings may not be used for dwelling purposes except as provided in 7.1.3 and 7.4.1 above.

View official code

Official source re-checked September 7, 2026: the cited page had not changed since it was quoted.

Full Breakdown

Section 7.1.5.4 of the Boone County Zoning Ordinance bars using accessory buildings for dwelling purposes except as provided in Section 7.1.3, the accessory-dwelling-unit standards. That means converting a detached garage, workshop, or other accessory structure into a bedroom, apartment, or full living unit is prohibited unless the project is permitted and built to the county's ADU rules: minimum 10-foot separation from the main house, unit capped at 75% of the primary home's square footage or 1,500 square feet, added off-street parking for larger units, and compliance with the Building Code, Zoning Regulations, and county health code.

Violations & Fines

Finishing a garage into an apartment or bedroom without approval as an accessory dwelling unit under Section 7.1.3 is a zoning violation subject to enforcement.

Frequently Asked Questions

Can I convert my garage into a bedroom in Boone County?
Not as a standalone conversion. Section 7.1.5.4 bars dwelling use of accessory buildings unless the space is permitted as an accessory dwelling unit under Section 7.1.3.
What if I just want extra living space, not a rental unit?
It still counts as dwelling use of an accessory building and must meet the Section 7.1.3 accessory-dwelling standards, including separate ownership and size limits.

Sources & Official References

Other rules in Boone County

Animal Ordinances: Chickens & LivestockSome RestrictionsADU RulesSome RestrictionsShed & Carport RulesSome RestrictionsNoise Ordinances: Aircraft NoiseSome RestrictionsNoise Ordinances: Decibel LimitsSome RestrictionsParking Rules: Driveway RulesSome RestrictionsParking Rules: Abandoned VehiclesSome RestrictionsFence Regulations: Retaining WallsSome Restrictions

All Boone County rules

Compare Boone County to another location·View the Missouri accessory structures overview

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Garage Conversions in Cities Across Boone County

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