Permit Required? Required
Typical Fee Range $1,500–$5,000 Total includes building, zoning review, and all mechanical, electrical, and plumbing trade permits.
Fee Method Valuation-based
Apply Online Apply at City of San Antonio Development Services Department →

What's Required in San Antonio

  • Required for all habitable secondary units with kitchen/bath facilities.
  • Maximum size is generally 1,100 sq ft or 50% of the main house square footage.
  • Owner must reside on the property (in either unit).
  • Must follow International Residential Code (IRC) for all habitable spaces.
  • Separate utility meters may be required depending on SAWS/CPS policies.
  • Zoning review ensures the ADU meets setback and density requirements.

How Much Does an ADU Permit Cost in San Antonio?

Budget $1,500–$5,000 for the San Antonio permit itself (valuation-based), issued by the City of San Antonio Development Services Department — but treat that as the entry fee, not the total. ADUs are full dwelling units, so the permit stack usually includes building, electrical, plumbing, and mechanical trade permits, plus plan review. One local note: total includes building, zoning review, and all mechanical, electrical, and plumbing trade permits. Get an itemized fee estimate from the department before finalizing your budget; the spread between a simple conversion and a new detached build is wide.

ADU Size Limits and Zoning Rules in San Antonio

Before drawing plans, check the two gates that sink most ADU projects: size and zoning. Size ceilings vary by lot and ADU type (attached, detached, or conversion), so confirm your specific configuration. Other recorded conditions: owner must reside on the property (in either unit). Setbacks, height limits, and utility connections layer on top of those rules. The City of San Antonio Development Services Department can confirm what your specific lot allows — worth doing before you pay for architectural drawings rather than after.

How to Get a ADU Permit in San Antonio

1

Step 1: Zoning Review

Consult a DSD Planner to verify ADU allowance on your lot.

2

Step 2: Full Plan Design

Hire a professional for full IRC-compliant architectural and MEP plans.

3

Step 3: BuildSA Submission

Apply for 'Residential New Construction' for the ADU unit.

4

Step 4: Permit Payment

Pay building and impact fees (estimated $1,500+ total).

5

Step 5: Full Inspections

Schedule the same inspection sequence as a new home (Slab, Frame, Trades, Final).

Frequently Asked Questions

Yes, provided you meet size and owner-occupancy requirements.
Permit fees generally range from $1,500 to $5,000, not including construction.
Up to 1,100 sq ft or 50% of the primary dwelling's size.