ADU Permit Guide for San Antonio, Texas — Step-by-Step Process (2026)

Before you contact the city about ADU permits, gather these documents to verify your property qualifies. San Antonio treats ADUs as accessory dwelling units under the Unified Development Code, requiring the same foundation as any residential construction project.

• Required Documentation:
• Property deed or title report showing clear ownership
• Current property tax statement from Bexar County
• Existing home's certificate of occupancy (if available)
• Property survey (required within 5 years for setback verification)

Property Qualification Checklist: Your property must contain a legal primary dwelling that's been occupied as a residence. Mobile homes, RVs, and unpermitted structures don't qualify as primary dwellings. The lot must be zoned for residential use in R-20, R-4, or R-6 districts. Mixed-use and commercial zones require separate variance processes.

Use the city's GIS portal /search to verify your zoning designation. Enter your address and look for "Zoning" in the property details. If your property shows "PUD" (Planned Unit Development), you'll need additional HOA approval before applying.

Disqualifying Factors: Properties in historic districts face additional design review requirements that add 30-45 days to the process. Lots under 5,000 square feet in R-20 zones rarely have sufficient setback space for ADUs. Properties with existing code violations must resolve all issues before ADU permit submission.

Floodplain properties require additional engineering studies and FEMA compliance documentation, adding $3,000-$5,000 in costs and 6-8 weeks to the timeline. Check your flood zone status using the FEMA map portal before proceeding.

Homeowners Association Requirements: HOAs can prohibit ADUs even when city zoning allows them. Request written confirmation from your HOA that ADUs are permitted in your subdivision. This approval letter becomes part of your permit application package.

The city requires proof that your primary dwelling has active utility connections and valid certificates of occupancy. Properties with septic systems need soil percolation tests to confirm capacity for additional wastewater load before permit approval.

San Antonio requires 5-foot minimum setbacks from side property lines and 20-foot setbacks from rear property lines for ADUs in most residential zones. These setback requirements eliminate many smaller lots from ADU consideration before you spend money on design.

• Zoning-Specific Requirements:
• R-20 zones: Maximum 30% lot coverage, 25-foot height limit
• R-4 zones: Maximum 40% lot coverage, 35-foot height limit
• R-6 zones: Maximum 45% lot coverage, 35-foot height limit

Calculate your available building area using the city's setback requirements. Measure from your property lines inward: 5 feet from sides, 20 feet from rear, and 25 feet from front property line. The remaining area determines your maximum ADU footprint.

Utility Capacity Verification: Contact SAWS (San Antonio Water System) at 210-704-7297 to verify water and sewer capacity for additional dwelling units. This conversation costs nothing but prevents expensive utility upgrade requirements discovered during plan review. Ask specifically about water pressure and sewer line capacity at your address.

SAWS requires separate utility meters for ADUs, costing $750-$1,200 for new connections. Properties with older service lines may need complete replacement, adding $3,000-$8,000 to your project cost.

Pre-Application Meetings: The Development Services Department offers pre-application consultations for $150. Schedule these meetings online through the city's portal or call 210-207-1111. Bring your property survey, proposed ADU location sketch, and utility capacity confirmation.

During pre-application meetings, staff reviews zoning compliance, identifies potential issues, and confirms required permit types. This 30-minute investment prevents costly design mistakes and gives you realistic timeline expectations.

Tree Preservation Requirements: San Antonio's tree preservation ordinance protects heritage trees over 24-inch diameter. If your proposed ADU location affects protected trees, add 4-6 weeks for arborist reports and alternative design reviews. The city maintains a qualified arborist list for required tree assessments.

Properties in the Edwards Aquifer recharge zone face additional impervious cover limits and stormwater management requirements. Check the SAWS aquifer map to determine if these regulations affect your project scope and budget.

San Antonio requires full architectural plans for ADU permits, not simple sketches or conceptual drawings. Your plan set must include site plan, floor plan, elevations, foundation plan, electrical plan, plumbing plan, and structural calculations sealed by a Texas-licensed engineer.

• Required Plan Components:
• Site Plan: Property boundaries, setbacks, existing structures, proposed ADU location, utility connections, parking spaces, and drainage patterns
• Floor Plan: Room layouts, dimensions, door/window locations, fixture placement, and emergency egress routes
• Elevations: All four exterior walls showing materials, heights, roof lines, and architectural details
• Foundation Plan: Footing details, slab specifications, and soil bearing calculations

All plans require wet signature stamps from Texas-licensed architects or engineers. Plan stamping costs $800-$1,500 depending on project complexity and professional relationships.

Energy Code Compliance: ADUs must meet current International Energy Conservation Code (IECC) standards. Your plans must include insulation specifications, window U-values, HVAC efficiency ratings, and air sealing details. Energy code violations are the most common plan review rejection reason.

Include a completed Manual J heating/cooling load calculation with your HVAC plans. This engineering analysis costs $300-$500 but prevents oversized equipment installations that fail inspection.

Structural Engineering Requirements: Texas requires sealed structural calculations for all new dwelling construction. Foundation design must account for local clay soil conditions and provide proper drainage around the structure. Structural engineering typically costs $1,200-$2,500 for ADU projects.

Pre-Approved Plan Options: San Antonio doesn't offer pre-approved ADU plans, but several local architects sell standardized designs for $2,000-$4,000. These plans still require site-specific modifications for your property's unique conditions, setbacks, and utility connections.

Popular local firms offering ADU plan sets include Clayton Korte, Redbud Design, and ADU Austin (which serves San Antonio). Pre-designed plans reduce design time from 6-8 weeks to 2-3 weeks but still require professional customization.

Plan Review Standards: City reviewers check plans for code compliance, not aesthetic preferences. Focus your design energy on meeting setback requirements, providing required parking, and showing clear emergency egress paths. Decorative elements don't affect approval timelines but code violations create costly delays.

Submit plans showing exact dimensions for all setbacks, room sizes, and ceiling heights. Plans lacking specific measurements get rejected immediately, adding 2-3 weeks to your timeline for resubmission.

San Antonio accepts permit applications through the ProjectDox online portal Monday through Friday, 8:00 AM to 5:00 PM. Create your account at least one week before submission to resolve any login issues without delaying your application.

• Complete Document Checklist:
• Completed building permit application (Form BPA-1)
• Property survey (dated within 5 years)
• Complete architectural plan set (minimum 6 sheets)
• Structural calculations with engineer's seal
• Energy compliance documentation (Form EC-1)
• HOA approval letter (if applicable)
• Contractor license verification
• Permit fee payment ($3,000-$8,000 depending on square footage)

Permit Fee Structure: Base permit fees start at $3,000 for ADUs under 600 square feet and scale upward based on construction value. Calculate fees using $225 per square foot for construction value, then apply the city's fee schedule. Additional fees include plan review ($450), electrical review ($275), and plumbing review ($225).

Submit applications before 3:00 PM for same-day processing into the review queue. Late submissions get processed the following business day, potentially adding one week to your timeline during busy periods.

Application Form Completion: Form BPA-1 requires specific contractor information, including license numbers and insurance certificates. Unlicensed contractors cannot pull permits for ADU construction in San Antonio. Verify your contractor's license status through the Texas Department of Licensing{:target="_blank"} before submission.

List the project as "New Accessory Dwelling Unit" in the construction type field. Selecting "Addition" or "Remodel" routes your application to wrong reviewers and delays processing by 1-2 weeks.

Common Submission Mistakes: Incomplete plan sets account for 40% of application rejections. Verify that all required sheets contain professional seals, legible dimensions, and current code references before uploading. Missing structural calculations automatically trigger rejection without review.

Upload all documents as PDF files smaller than 10MB each. Oversized files corrupt during upload and appear blank to reviewers. Split large plan sets into multiple files labeled clearly: "Sheet 1-3," "Sheet 4-6," etc.

Payment Processing: The city accepts credit cards, checks, and electronic transfers for permit fees. Credit card payments process immediately, while checks require 3-5 business days for clearance. Payment delays pause the review process until funds clear completely.

Keep payment confirmation numbers for tracking purposes. Application numbers are assigned within 24 hours of successful payment processing and fee clearance.

After submission, your ADU permit enters a multi-department review process lasting 4-8 months depending on application completeness and seasonal volume. Winter submissions typically process faster than spring applications due to lower seasonal demand.

1. Review Department Sequence:
2. Planning Department: Zoning compliance, setbacks, lot coverage (2-3 weeks)
3. Building Department: Structural plans, foundation design, code compliance (3-4 weeks)
4. Fire Department: Emergency access, fire separation requirements (1-2 weeks)
5. Public Works: Drainage, utility connections, right-of-way impacts (2-3 weeks)
6. Health Department: Septic systems only (1-2 weeks if applicable)

Each department reviews independently, but rejections from any department pause the entire process until corrections are submitted and approved.

Plan Check Comments: Reviewers provide written comments listing specific code violations and required corrections. Comments reference exact code sections and describe necessary plan changes. Typical comment periods last 2-3 weeks from review completion.

• Common plan check comments include:
• "Show 5-foot minimum setback dimensions on site plan"
• "Provide structural calculations for beam spans over 8 feet"
• "Add emergency egress window details to bedroom elevations"
• "Include HVAC load calculations per IECC requirements"

Correction and Resubmission Process: You have 180 days to respond to plan check comments before applications expire. Most corrections require architectural revisions costing $500-$1,500 depending on complexity. Simple dimensional changes cost less than structural redesigns.

Submit corrections through the same ProjectDox portal using your original application number. Clearly mark revised plan areas with revision clouds and date stamps. Reviewers only examine changed areas during resubmission reviews.

Review Timeline Management: Track your application status using the ProjectDox portal's status updates. Applications showing "Under Review" are actively being examined. "Pending Corrections" status means you've received comments requiring responses.

Second round reviews typically take 1-2 weeks since reviewers focus only on corrected items. Third round reviews indicate significant plan problems and may require professional design assistance to resolve properly.

Expedited Review Options: San Antonio offers expedited review services for additional fees ranging from $1,000-$3,000. Expedited applications receive priority processing but don't bypass code compliance requirements. This service reduces timeline by 4-6 weeks during busy seasons.

Contact the Development Services Department at 210-207-1111 to request expedited review during initial submission. Expedited status cannot be added to applications already in standard review queues.

After permit approval, you have 180 days to begin construction and 24 months to complete the project. Extensions require additional fees and updated code compliance if building codes change during construction delays.

1. Required Inspection Sequence:
2. Foundation/Footing: Before concrete pour (24-48 hour notice)
3. Framing: After structural completion, before insulation (48-72 hour notice)
4. Electrical Rough-in: Before wall closure, after electrical installation
5. Plumbing Rough-in: Before wall closure, after supply/waste lines
6. Mechanical Rough-in: After HVAC installation, before insulation
7. Insulation: Before drywall installation
8. Final: After all finish work completion

Schedule inspections through the city's automated system at 210-207-0900 or online portal. Inspections scheduled before 2:00 PM typically occur the next business day. Late requests may wait 2-3 days during busy periods.

Inspection Preparation: Inspectors arrive between 8:00 AM and 4:00 PM within the scheduled timeframe. Ensure construction areas are accessible, well-lit, and clear of debris. Contractors or property owners must be present during inspections for immediate question responses.

Keep permit cards visible at job sites and have approved plans available for inspector reference. Missing documentation can result in inspection delays or failures requiring rescheduling.

Failed Inspection Process: Failed inspections receive written correction notices listing specific violations and required fixes. Common failures include improper electrical connections, missing structural hardware, and inadequate insulation installation.

Contractors have unlimited attempts to pass inspections, but each failure adds 1-2 days to project timelines for correction and rescheduling. Repeated failures in the same category may trigger additional plan review requirements.

Final Inspection Requirements: Final inspections verify that construction matches approved plans and all systems function properly. Inspectors check smoke detectors, electrical panels, plumbing fixtures, HVAC operation, and emergency egress compliance.

Address any punch list items before scheduling final inspection. Incomplete finish work, missing fixtures, or non-functional systems automatically fail final inspection and delay certificate of occupancy issuance.

Inspection Record Keeping: Maintain all inspection records and correction notices for certificate of occupancy processing. Green tagged inspections indicate approval; red tags require corrections and reinspection before proceeding to subsequent phases.

Take photos documenting correction completion before reinspection requests. Visual evidence helps inspectors verify compliance and can expedite approval processes for minor correction items.

After passing final inspection, request your certificate of occupancy through the same ProjectDox portal used for permit applications. Certificate processing takes 5-10 business days and costs $150 as part of the original permit fees.

Certificate of Occupancy Requirements: The city verifies that construction matches approved plans, all inspections passed, and utility connections are active. SAWS must confirm water and sewer service activation before certificate issuance.

Submit a completed Form CO-1 with final inspection approval documentation. Include utility activation confirmations from SAWS, CPS Energy for electrical service, and applicable internet/cable providers for communication services.

Address Assignment Process: New ADUs require separate addresses for postal delivery and emergency services. Submit address assignment requests through the Development Services Department concurrent with certificate of occupancy applications.

Address assignment takes 2-3 weeks and coordinates with Bexar County Appraisal District for property tax assessment updates. New addresses become official when certificates of occupancy are issued.

Utility Connection Timeline: SAWS typically activates water and sewer service within 3-5 business days after final plumbing inspection approval. Electrical service activation through CPS Energy requires 1-2 business days after electrical final inspection.

Schedule utility activations before requesting certificate of occupancy to prevent processing delays. Inactive utilities automatically delay certificate approval until service confirmations are received.

Legal Rental Status: You cannot legally rent your ADU until receiving the certificate of occupancy. Renting before certificate issuance violates city codes and can result in $500-$2,000 daily fines until compliance is achieved.

Insurance companies require certificate of occupancy documentation before covering rental activities. Contact your insurance provider during the certificate application process to coordinate coverage activation timing.

County Recording Requirements: Bexar County Appraisal District automatically updates property records when certificates of occupancy are issued. New ADU assessments typically appear on tax bills within 6-12 months following completion.

ADU additions may increase property values by $40,000-$80,000 depending on size and finishes. Budget for increased property taxes starting the year following certificate of occupancy issuance.

The completed ADU becomes part of your property's permanent legal description and appears on future title reports and property surveys.

Understanding common rejection reasons helps you avoid expensive delays and redesign costs during the permit process. These issues account for 75% of application rejections in San Antonio's Development Services Department.

Setback Violations (35% of rejections): Many applications show ADUs too close to property lines or existing structures. San Antonio requires 5-foot minimum side setbacks and 20-foot rear setbacks in most zones. Measure carefully from actual property lines, not fence lines, which often don't match legal boundaries.

Order a current property survey before design begins. Surveys older than 5 years may not reflect current property line positions due to fence adjustments or boundary disputes. New surveys cost $800-$1,200 but prevent costly design revisions.

Incomplete or Unsealed Plans (25% of rejections): Plans lacking professional engineer or architect seals get rejected immediately. Texas requires sealed structural calculations and architectural plans for all new dwelling construction, including ADUs.

Verify that all plan sheets contain current professional seals with legible license numbers and signatures. Expired licenses or missing seals trigger automatic rejections adding 2-3 weeks to resubmission timelines.

Utility Capacity Issues (15% of rejections): Properties with inadequate water pressure or sewer capacity cannot support additional dwelling units. Older neighborhoods may have undersized utility infrastructure requiring expensive upgrades before ADU approval.

Contact SAWS early in the design process to verify utility capacity at your specific address. Capacity upgrades can cost $5,000-$15,000 and take 6-12 weeks to complete, significantly impacting project budgets and timelines.

Parking Requirements (10% of rejections): San Antonio requires one parking space per ADU bedroom in addition to existing primary dwelling parking requirements. Properties lacking adequate parking space must modify designs to reduce bedroom counts.

Each parking space requires 9x18 feet of accessible area connected to public streets or alleys. Include parking space dimensions and access routes on site plans to demonstrate compliance with city requirements.

Historic District Restrictions (8% of rejections): Properties in designated historic districts face additional design review requirements and architectural style restrictions. Historic review adds 30-45 days to permit timelines and may require design modifications.

Check historic district boundaries using the city's GIS system /search before beginning design work. Historic properties often require specific materials, roof lines, and window styles matching neighborhood character.

Tree Preservation Conflicts (7% of rejections): San Antonio's tree preservation ordinance protects heritage trees over 24-inch diameter measured 4.5 feet above ground. ADU locations affecting protected trees require arborist reports and alternative design solutions.

Identify large trees on your property and measure diameters before selecting ADU locations. Tree removal permits cost $500-$1,500 and require city approval before construction begins. Protected tree removal may be prohibited entirely, requiring design relocations.

Prevention Strategies: Schedule pre-application meetings with Development Services staff to identify potential issues before investing in architectural plans. These $150 consultations provide specific guidance for your property's unique conditions and constraints.

Use the city's online zoning verification tools /tools/codes/san-antonio to confirm current zoning requirements and setback standards for your property. Zoning requirements change periodically, and outdated information leads to plan rejections and redesign costs.