Before You Apply: Research and Planning
Applying for a building permit without adequate preparation is one of the most common and costly mistakes homeowners and contractors make. Plan check fees are non-refundable in most cities even if your project is redesigned or abandoned after submission. Corrections that require resubmitting plans add weeks or months to your timeline. The investment in thorough preparation before submitting your first set of plans pays for itself many times over. Here is what you need to know before you submit a permit application: **Confirm your zoning.** Look up your property's zone designation using your city's GIS zoning map. Know your zone before you design anything — setbacks, height limits, and lot coverage maximums must be reflected in your plans. In Los Angeles, use ZIMAS (zimas.lacity.org) for parcel-level zoning data. In Austin, use the interactive zoning map at austintexas.gov/page/zoning. In Denver, use Denver's Community Planning and Development GIS portal at gis.denvergov.org. **Check for applicable overlays.** Historic preservation overlay zones, hillside areas, coastal zones, and specific plan areas impose additional requirements beyond the base zone. An application submitted without addressing overlay requirements will be flagged during plan check. Discovering an overlay after submitting plans typically requires plan revisions. **Determine whether a permit is required.** Use your city's building department resources to confirm that your specific project requires a permit. See PropertyZoned's 'Do I Need a Building Permit?' guide and the Permit Checklist tool at propertyzoned.com/tools/permit-checklist for a city-specific breakdown of what requires permits and what is exempt. **Calculate setbacks and coverage.** Before engaging an architect, do the preliminary math: what are the required setbacks in your zone? What is the maximum lot coverage? What are the height limits? These parameters define the envelope within which your project must fit. Starting a design without knowing these constraints wastes design fees and time. **Review state law preemptions.** In California, ADU projects benefit from state law preemptions (ministerial approval, 4-foot setbacks, waived impact fees for under 750 sqft) that override local restrictions. In Colorado, HB 24-1175 requires ministerial ADU approval. In Washington, HB 1337 governs ADU permitting. Knowing which state laws apply to your project can unlock rights that exceed what local rules would otherwise provide.
Gathering Required Documents
Every building permit application requires a specific set of documents. The exact requirements vary by city and project type, but the following documents are commonly required for most residential permit applications: **Site plan:** A scaled drawing of your property showing: the lot boundaries (with dimensions), all existing structures, the proposed new structure or addition (with dimensions), setback distances from property lines to existing and proposed structures, driveway and parking areas, and any utility easements. Most building departments require site plans at 1:20 or 1:40 scale. **Floor plans:** Scaled drawings showing the layout of all habitable spaces — room dimensions, door and window locations, bathroom and kitchen layouts, and identification of room uses. For ADUs, floor plans must show both the primary dwelling and the ADU to establish the relationship between them. **Elevations:** Drawings showing the exterior faces of the building from all four sides — indicating height, window sizes, door locations, material finishes, and the relationship to grade. Elevations are required for any new construction or addition. **Foundation plan:** For new construction or structural additions, a foundation plan showing the foundation type (slab, raised, basement), dimensions, and structural specifications. In California, foundations must comply with CBC Chapter 19. In Texas, a geotechnical investigation may be required on expansive soils. **Structural calculations and plans:** For projects involving structural systems — new beams, point loads, retaining walls over 4 feet — structural engineering calculations stamped by a licensed structural engineer are required. Residential additions under certain size thresholds can use prescriptive compliance (following code tables) rather than engineered calculations, which reduces cost. **Title 24 (energy compliance) — California only:** California requires an energy compliance calculation showing that the project meets the California Energy Code (Title 24 Part 6). For residential projects in California, this typically means a HERS (Home Energy Rating System) documentation package showing insulation, window performance, and HVAC system specifications meet the 2022 standards. **Proof of ownership or contractor license:** Many cities require proof that the permit applicant is the property owner or a licensed contractor authorized to pull the permit. Owner-builder permits are available for homeowners who will do their own work, but some cities impose restrictions on owner-builder permits for certain project types.
Submitting Your Application: Online Portals and In-Person
Most major US cities now offer online permit application portals that allow you to submit plans electronically, pay fees by credit card, and track review status without visiting a permit counter. Online submission has become the standard in most California cities and is increasingly available elsewhere. **Los Angeles (LADBS):** The primary portal for residential permit applications is LADBS Services at ladbsservices2.lacity.org. The portal accepts electronic plan submittals (PDF format required), online fee payment, and inspection scheduling. For ADUs, LADBS offers the ADU Express program specifically designed for streamlined review. LADBS's main customer service number is (213) 482-0000. Address: Multiple district offices throughout the city — check the LADBS website for the office serving your district. **Austin (DSD):** Austin's primary portal is Austin Build + Connect (Austin B+C) at abc.austintexas.gov. All residential permit applications in Austin are submitted electronically through Austin B+C. The portal allows plan upload in PDF format, fee payment, review status tracking, and inspection scheduling. DSD's main phone: (512) 978-4000. Austin's ADU permits — including the significant water/wastewater and transportation impact fees ($3,000-$15,000 range) — are processed through this system. **Denver (CPD):** Denver's Community Planning and Development (CPD) processes permits through the Accela Citizen Access portal at denvergov.org/permits. Electronic submittals accepted. Impact of Colorado HB 24-1175 (2024): Denver must process ministerial ADU permits without discretionary review — this has streamlined the ADU pathway specifically. CPD main line: available through denvergov.org/cpd. **Phoenix (PDD):** Phoenix Development Services Department accepts electronic permit applications through its ProjectDox electronic plan review system at phoenix.gov/pdd. Phoenix is generally noted for faster permit processing times than California cities. **Seattle (SDCI):** Seattle Department of Construction and Inspections (SDCI) processes residential permits through the Seattle Services Portal at seattle.gov/sdci/permits. Seattle's ADU permit fees typically run $4,000-$12,000 with additional school impact fees. Washington HB 1337 (2023) requires ministerial ADU approval in Seattle. For all cities: check your building department's website for the current list of accepted file formats, plan organization requirements, and digital signature requirements. Submitting plans that do not meet format requirements can result in immediate rejection and delay.
The Plan Check Review Process
After you submit your application and plans, the plan check review phase begins. This is the period during which building department plan examiners review your submitted documents for compliance with applicable codes, standards, and local requirements. Plan check is often the longest waiting period in the permit process. **Plan check timelines by city:** - Los Angeles ADU Express: 2-4 weeks for standard ADUs (ministerial approval required within 60 days per California Government Code 65852.2(a)(3)) - Austin standard residential: 2-4 months (longer than California due to Austin DSD review queues) - Denver ADU (post-HB 24-1175): ministerial approval required; target 4-6 weeks - Phoenix residential: 2-4 weeks (Phoenix is generally faster than CA or TX) - Seattle residential ADU: 4-8 weeks (Washington HB 1337 ministerial approval required) - New York City residential: 3-6 months (longest of major US cities) During plan check, examiners verify compliance with: the zoning code (setbacks, height, coverage), the building code (structural, fire, egress, mechanical), the energy code (California Title 24 or applicable state code), and any overlay district or special area requirements that apply to your property. **First-round corrections.** It is very common to receive a plan check correction list on the first review cycle. This is not a denial — it is a request for revisions or additional information. Most residential projects receive at least one correction cycle. Review the correction list carefully, address each item, and resubmit revised plans. Partially addressing corrections and assuming the examiner will approve the rest is a common mistake that triggers additional correction cycles. **Over-the-counter (OTC) permits.** For simple, clearly-defined project types, some cities issue permits over the counter (or in an expedited online equivalent) without a full plan check cycle. Los Angeles offers OTC permits for: small residential solar systems through SolarAPP+, standard water heater replacements, like-for-like HVAC replacements, and some simple electrical and plumbing work. Portland offers 'express permits' for pre-approved projects. Austin's online portal speeds up processing for simple project types.
Addressing Corrections and Receiving the Permit
When the plan examiner returns your plans with a correction list, your job is to systematically address each correction and resubmit. Here is how to do this efficiently: **Read the corrections carefully.** Each correction note should cite a specific code section being triggered. Understanding what code section is being cited helps you respond correctly. If a correction is unclear, call the plan examiner for clarification before resubmitting — an incorrect response to a correction triggers another correction cycle. **Respond to every comment.** A common resubmittal mistake is addressing most of the corrections but not all. Unaddressed comments will recur on the next review. Some building departments use response-to-comments sheets where you must document your response to each item. Even where these are not required, using one is good practice. **Know when to consult a professional.** Some corrections require structural engineering calculations, energy compliance documentation, or specialized knowledge. If you receive a correction that requires information you cannot provide yourself (engineering calculations, energy compliance certification), hire the appropriate professional rather than attempting to respond without expertise. An incorrect engineering response can halt your project entirely. **After approval, receive the permit.** Once the plan examiner approves your corrected plans, the permit is issued. In most cities, you receive a permit number and a physical or digital permit document. The permit (or a laminated copy) must be posted at the project site and be visible from the street while construction is underway. In California, maintaining the permit on-site is required by the California Building Code. **Permit validity.** Building permits have expiration dates — typically 12 to 24 months from the date of issuance. Work must commence within a specified period (often 90 days or 6 months) after permit issuance, and inspections must be scheduled regularly to keep the permit active. A permit that expires before construction is complete requires reapplication, which may trigger compliance with updated codes that went into effect after the original permit was issued.
Construction Inspections: What to Expect
Building inspections are the mechanism by which the building department verifies that construction matches the approved plans and complies with all applicable codes. Required inspections vary by project type, but the typical sequence for a residential addition or ADU in a California city is: **1. Foundation inspection.** Scheduled after forms and reinforcing steel are set, before concrete is poured. The inspector verifies that the foundation dimensions, depth, and reinforcing match the approved foundation plan. This is a critical inspection — concrete poured without an approved foundation inspection cannot be removed easily. **2. Framing inspection.** Scheduled after framing is complete and before any insulation, drywall, or exterior sheathing covers structural elements. The inspector verifies framing dimensions, connections, shear wall placement, hold-downs, and header sizing. Also often combined with: rough electrical, rough plumbing, and rough mechanical inspections, all of which must be complete and visible before any surfaces are closed. **3. Rough electrical inspection.** Verifies that all electrical rough-in work (boxes, conduit, wire sizing, panel connections) complies with the California Electrical Code or applicable state code. All wiring must be visible and accessible — walls must not be closed before this inspection passes. **4. Rough plumbing inspection.** Verifies pipe sizing, slope for drain lines, vent installation, and connection points. Pressure test may be required. **5. Insulation inspection.** In California, an insulation inspection verifies that insulation R-values and installation quality meet Title 24 energy code requirements. California HERS rater field verification may be required for HVAC and duct work. **6. Drywall nailing/fireblocking inspection.** Some jurisdictions require inspection of drywall nailing patterns and fireblocking before drywall finishing, to verify fire separation assemblies. **7. Final inspection.** After all construction is complete, the final inspection verifies that the as-built condition matches the approved plans, all code requirements are met, and all previously-required inspections have passed. In California, the final inspection approval (for ADUs and residential additions) triggers the right to occupy the space. **Scheduling inspections:** In Los Angeles, inspections are scheduled through the LADBS online portal (ladbsservices2.lacity.org) or by phone. In Austin, through Austin B+C (abc.austintexas.gov). Most cities now offer online inspection scheduling. Always schedule with adequate lead time — inspectors are often booked 3-7 business days out.
Certificate of Occupancy and Common Mistakes to Avoid
The final step in the permit process is receiving the Certificate of Occupancy (CO) — the official document issued by the building department after the final inspection passes, legally authorizing the space for occupancy. The CO is the document that officially creates a legal dwelling unit. For ADUs, the CO is required for legal rental. Without a CO, occupying the space exposes you to code enforcement action. For ADUs and secondary units, the CO is particularly important. An ADU without a CO is considered an 'illegal unit' even if it was built with a permit but never had a final inspection and CO issued. This is a surprisingly common situation — homeowners build with a permit, run out of money during construction, or let the permit expire without getting a final inspection. Resolving an unpermitted or CO-lacking ADU is more complex than getting the CO properly in the first place. **Common mistakes in the permit process:** **1. Starting construction before the permit is issued.** Constructing before receiving the permit is an automatic violation in every jurisdiction. Stop-work orders are issued, work must halt, and retroactive permits with penalties must be obtained. Never start work based on a submitted application — wait for the issued permit. **2. Deviating from approved plans without approval.** Once plans are approved and a permit is issued, the approved plans are the legal document. Any material deviation from the approved plans requires a plan check revision (sometimes called a field change, revision, or as-built revision). Deviating without approval results in failed inspections that require correction and re-inspection. **3. Missing inspections.** If you close up walls before a rough-in inspection, you fail the rough-in inspection and typically must open the walls for re-inspection. This is expensive and time-consuming. Schedule and pass all required inspections before covering any work. **4. Letting the permit expire.** Monitor your permit expiration date. Most permits require an inspection every 6-12 months to remain active. If you stop construction for an extended period, check your permit status and request an extension if needed before the permit expires. **5. Assuming online research replaces the permit process.** PropertyZoned's tools and guides — including the Permit Checklist at propertyzoned.com/tools/permit-checklist — are starting points for research, not substitutes for the formal permit process. Your building department is the final authority on what permits are required and what your specific project must comply with.
Frequently Asked Questions
How long does it take to get a building permit in California?
For ADUs and residential projects, California state law requires cities to process ministerial permit applications within 60 days. In practice, LA LADBS ADU Express targets 2-4 weeks for plan check. San Francisco DBI typically takes 2-6 weeks. Sacramento CDD typically takes 3-5 weeks. For non-ADU residential projects (additions, renovations), plan check timelines run 4-12 weeks depending on complexity and the city's current workload. Having complete, code-compliant plans on your first submittal significantly reduces the number of correction cycles and total timeline.
Do I need an architect to get a building permit?
For most residential projects in California, you need licensed architectural or structural drawings — but the designer does not always need to be a licensed architect. For projects under a certain size threshold (varies by jurisdiction), a licensed building designer or contractor may prepare the plans. For any project requiring structural engineering calculations, a licensed structural engineer must stamp those calculations. For larger additions and new ADU construction, a licensed architect is typically the most efficient and safest choice. Some cities (Los Angeles, San Diego) offer pre-approved ADU standard plans that eliminate the design cost entirely for eligible projects.
What happens during a building inspection?
A building inspector visits your project site to verify that construction matches the approved plans and complies with applicable building codes. The inspector checks specific components based on the inspection type: foundation inspections verify dimensions and reinforcing before concrete is poured; framing inspections verify structural members, connections, and load paths; rough-in inspections verify electrical, plumbing, and mechanical rough work before walls are closed; final inspections verify that the completed project matches the approved plans and that all code requirements are met. You must pass each required inspection before proceeding to the next construction phase.
How much does a building permit cost?
Permit fees vary by city and project type. In Los Angeles, residential permit fees are generally valuation-based (tied to construction cost). An ADU permit runs $2,000-$8,000 total. A deck permit runs $200-$1,500. A solar permit under 15kW runs $150-$500. In Austin, an ADU permit runs $3,000-$15,000 including impact fees (Austin's water/wastewater and transportation impact fees add $3,000-$8,000 beyond the base permit fee). Denver ADU permits run $2,000-$8,000. In general, California cities are lower in permit fees than Texas cities for similar projects because California waives ADU impact fees for units under 750 sqft while Texas cities do not.
What if I need to start construction before the permit is issued?
You cannot legally start construction before a permit is issued in any major US jurisdiction. The only exception is truly emergency work to prevent immediate danger or property damage (like boarding up a window after a storm), and even that typically must be followed immediately by a permit application. Starting construction without a permit results in: a stop-work order requiring all work to halt, retroactive permit fees plus a penalty (often 2-4x the permit fee), required opening of closed walls if rough-in inspections were skipped, and potential insurance coverage issues. The safest approach is always to have the permit in hand before construction begins.