Permit Required? Required
Typical Fee Range $1,000–$3,500 Includes building, zoning, and utility capacity fees.
Fee Method Valuation-based
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What's Required in Louisville

  • Building permit required for all secondary dwelling units.
  • Must contain independent cooking, sleeping, and sanitation facilities.
  • Requires professional architectural plans including foundation.
  • Must meet lot coverage and setback rules for the zoning district.
  • Owner-occupancy of the property is a mandatory requirement.
  • Maximum size capped (usually 800 sq ft or 30% of main house).

How to Get a ADU Permit in Louisville

1

Step 1: Zoning Verification

Confirm an ADU is allowed on your lot via the Planning dept.

2

Step 2: Design Documents

Prepare detailed site plans and architectural drawings.

3

Step 3: Submit Portal

Apply for a New Accessory Structure permit online.

4

Step 4: Multi-Agency Review

Checked by Building, Zoning, and Health departments.

5

Step 5: Inspections

Full series from footings to final certificate of occupancy.

Frequently Asked Questions

Yes, provided it meets all building and safety codes for habitation.
In some cases, ADUs can share meters with the main house.
New ADU builds typically take 4-6 weeks for full review.