City guide

Building a backyard home in McKinney

McKinney publishes its own ADU guide — a city that wants you to succeed.

What McKinney allows

Eligibility

Single-family residential zoning with room to meet regulations. Planned Development (PD) zones may not allow an ADU — address-specific check required.

ADU size

Main home under 1,200 sq ft → ADU up to 75% of its area. Main home 1,200 sq ft or more → up to 50%.

Height & setbacks

ADU cannot exceed the main house height; setbacks match the main home's zoning district.

Parking

4+ existing spaces → none added; fewer → add 1; Historic Overlay District → 3 total.

Utilities

The ADU shares the main home's meters — no separate electric account.

The catch most people miss

PD zoning. A large share of newer McKinney neighborhoods sit in Planned Developments with their own rules — the city's general ADU rules may not apply to your address. This is exactly what our report checks first.

What it costs

The unit price you see advertised — the number on an online listing for the structure itself — is only part of the real cost: site work, utilities, permits, and delivery/crane are the rest. Check your property for a rule-based upper bound, then request help and we'll connect you with independent local professionals who can price the real number for your address.

Rules verified 2026-07-12 from Building an ADU in McKinney (official city guide). General guidance, not a determination for a specific property — zoning overlays, planned developments, and HOA/deed restrictions are address-specific.