Who can draw ADU plans, in brief
There is no single answer, because an ADU permit set is several drawings and the law reaches each one separately. In Los Angeles, an unlicensed person may prepare the architectural plans for a two-story single-family dwelling, and only the structural drawings carry a licensed signature, where engineering details appear [1]. In Arizona, a nonregistrant may design a detached single-family dwelling (A.R.S. 32-144(A)) [2]. Texas's Architects Act exemptions in Occupations Code 1051.606(a)(4) are written for private commercial and smaller multifamily buildings [4, 5].
The site plan is a layer of its own. Some departments say a residential site plan need not be drawn or sealed by a licensed professional [6, 7], with Scranton, Pennsylvania as an illustrative example [8], and a few require a sealed survey [9]. Innowave Studio draws ADU site plans; the general version of the question, for commercial sites, is answered in who prepares a site plan and do I need an architect for a site plan.
The layers of an ADU plan set
| Layer | What the jurisdiction's rule says |
|---|---|
| Site plan | Metro Nashville does not require residential site plans to be done by a licensed professional, but they must be an accurately dimensioned scale drawing [6]; Wendell, North Carolina says the site plan for a residential structure does not have to be professionally drawn [7] |
| Site plan (an illustrative example) | Scranton, Pennsylvania: most residential plot plans need no professional seal or stamp if you know where your property line is [8] |
| Survey | Cobb County, Georgia: before a building permit, the permittee or landowner files a current plan and survey sealed by a registered land surveyor (Development Standards s.103.19.1) [9]; Pasadena's ADU standard plans program: a property line survey for new construction within 5 ft of a property line [10] |
| Survey or site plan | Houston, for a residential addition: a survey by a Texas registered surveyor or a complete site plan with dimensions [11] |
| Architectural plans | Los Angeles: an unlicensed person may prepare them for a two-story single-family dwelling [1]; Arizona: a nonregistrant may design a detached single-family dwelling (A.R.S. 32-144(A)) [2] |
| Structural drawings | Los Angeles: a licensed signature where engineering details appear [1]; Dublin, California: a licensed professional when the building is one story with a basement or more than one story (Policy BDP 17) [12]; Milpitas, California: its exemptions apply to plans designed to the conventional framing of Chapter 23 of the 2025 California Building Code [13] |
| Final plan set | Los Angeles County's one- and two-family dwelling plan review list (v2.0, 1-1-2023) asks for final plans "stamped and signed by the California registered architect or engineer when appropriate" [14] |
The table shows why "do I need an architect" has a layered answer. One set can hold an unsealed site plan and structural drawings a licensee signs: Nashville accepts the first [6], and Los Angeles asks for the second where engineering details appear [1]. In Cobb County, a current plan and survey sealed by a registered land surveyor comes before the building permit [9].
California: the city policies
California's building departments publish their own lines between what anyone may draw and what a licensee signs:
- Los Angeles. The Department of Building and Safety's policy on stamped plans lets an unlicensed person prepare the architectural plans for a two-story single-family dwelling; the structural drawings need a licensed signature where engineering details appear [1].
- Dublin. Policy BDP 17 calls for a licensed professional on the structural plans when the building is one story with a basement, or more than one story [12].
- Milpitas. Its handout on plans that must be designed by an architect or engineer applies its exemptions to plans designed to the conventional framing of Chapter 23 of the 2025 California Building Code [13].
- Los Angeles County. Final plans are "stamped and signed by the California registered architect or engineer when appropriate" [14].
California's statewide rule is not stated here: the rows above are city and county policies, each holding in its own jurisdiction. The state's ADU site rules are in California ADU site fit, and its wider site plan rules on the California site plan page.
Arizona: the statute and the Board's marking rule
Arizona sets the line in statute and in a Board rule:
| Rule | What it provides |
|---|---|
| A.R.S. 32-144(A) | A nonregistrant may design a detached single-family dwelling [2] |
| A.R.S. 32-144(A)(4) | A nonregistrant may design "a one or two story building or structure" of up to 3,000 sq ft, not for more than 20 persons continuously, with spans of 20 ft or less unless engineered trusses are used [2] |
| A.A.C. R4-30-304(A) | A registrant's seal and signature go on each drawing sheet, the specification cover, reports and letters (Supp. 24-1) [3] |
| A.A.C. R4-30-304(D) | A registrant seals before submitting to "any regulatory or review body," "unless the document is marked 'preliminary,' 'draft,' or 'not for construction'" [3] |
The marking rule is the basis on which an unsealed preliminary plan reaches an Arizona review body: it carries one of the three words [3].
Texas: the Occupations Code line
Texas draws its architect line in the Occupations Code. Section 1051.606(a)(4) exempts from the Architects Act a private commercial building of not more than 2 stories or 20,000 sq ft, the exemption at 1051.606(a)(4)(D), and a multifamily building of not more than 2 stories and 16 units per building [4, 5]. The rule for a one-family dwelling or an ADU in Texas was not read in our research. The state's commercial seal lines are on the Texas site plan page.
Pre-approved catalogs: who may submit a plan
Catalog programs set their own rule on who submits. Scotts Valley limits plan submitters to "licensed professionals" and San Ramon to "qualified professionals" [15, 16]. Arizona's ARS 9-461.19, cited from the enacted text of SB 1529, says a municipality "may not restrict who may submit" [17]. The site plan that goes with a catalog plan is covered in site plans for pre-approved ADUs.
Where the studio's site plan fits
Innowave Studio draws the site plan layer of an ADU set: the lot and its lines, the house, the ADU footprint dimensioned to each line, separation, driveway, parking and the easements of record, with a site data table. Plans are preliminary, and engineering is by your engineer of record. Where a jurisdiction requires a seal, as Cobb County does for the survey and Los Angeles does for structural drawings with engineering details, the sealed sheet comes from the licensee, and the preliminary plan is what the engineer of record builds on [9, 1]. The state ADU statutes are in ADU laws by state.
How to order an ADU site plan
- Open start a project and choose Residential: ADU (accessory dwelling unit) as the project type, with single-family and townhome as the asset class.
- Give the city or county and the state, so the plan follows that jurisdiction's checklist and its rule on who prepares what.
- Under program and stage, describe the ADU and say who is drawing the building plans and, where one is needed, who is sealing the survey or the structural sheets.
- Attach one file, the most useful you have: a survey, or a sketch with measurements. If the department has given you a checklist or reviewer comments, name them under program and stage.
The studio reads the brief, checks the jurisdiction's rules and replies by email to scope the plan. Other permit plans are on permit site plans. To order the site plan for your ADU, start a project and choose Residential: ADU (accessory dwelling unit).
Frequently asked questions
Do I need an architect to draw ADU plans?
Who has to sign the structural drawings?
Can I draw the site plan for my ADU myself?
Do I need a survey for an ADU?
Where the department says so. Cobb County, Georgia requires a current plan and survey sealed by a registered land surveyor before a building permit (Development Standards s.103.19.1) [9], and Pasadena's ADU standard plans program asks for a property line survey for new construction within 5 ft of a property line [10].
Can an unsealed plan be submitted in Arizona?
A registrant seals before submitting to a regulatory or review body unless the document is marked "preliminary," "draft" or "not for construction" (A.A.C. R4-30-304(D)) [3].
Where does the seal go on an Arizona plan set?
A registrant's seal and signature go on each drawing sheet, the specification cover, reports and letters (A.A.C. R4-30-304(A), Supp. 24-1) [3].
Sources
- 1)Information Bulletin P/BC 2023-073, Policy 4: Stamped Plans, City of Los Angeles, Department of Building and Safety. Accessed 2026-10-10.
- 2)A.R.S. 32-144, Exemptions and limitations; definition, Arizona State Legislature. Accessed 2026-10-10.
- 3)A.A.C. R4-30-304, Use of Seals (Supp. 24-1), Arizona State Board of Technical Registration. Accessed 2026-10-10.
- 4)Occupations Code 1051.606, architect exemptions (Texas Legislature; text via texas.public.law), Texas Legislature (text via texas.public.law). Accessed 2026-10-10.
- 5)When to Engage an Architect or Excepted Engineer (flow chart), City of Abilene, Texas. Accessed 2026-10-10.
- 6)Residential Permit Procedures (brochure), Metropolitan Government of Nashville and Davidson County, Codes Administration. Accessed 2026-10-10.
- 7)Building Permits, Town of Wendell, North Carolina, Planning Department. Accessed 2026-10-10.
- 8)Plot Plan Instructions, City of Scranton, Pennsylvania. Accessed 2026-10-10.
- 9)2026 Variance Application and Schedule, citing Development Standards s.103.19.1, Cobb County, Georgia. Accessed 2026-10-10.
- 10)ADU Standard Plans Program, City of Pasadena, California, Planning and Community Development Department. Accessed 2026-10-10.
- 11)Residential Permitting 101, City of Houston, Houston Permitting Center. Accessed 2026-10-10.
- 12)Policy BDP 17 (original effective date August 16, 2001), City of Dublin, California, Building and Safety. Accessed 2026-10-10.
- 13)Plans Required to be Designed by Architect or Engineer, City of Milpitas, California, Office of Building Safety. Accessed 2026-10-10.
- 14)One- and Two-Family Dwelling Plan Review List (v2.0, 1-1-2023), Los Angeles County Public Works, Building and Safety. Accessed 2026-10-10.
- 15)AB 1332: Pre-Approved ADU Program, City of Scotts Valley, California. Accessed 2026-10-10.
- 16)Accessory Dwelling Units (Permit Ready ADU), City of San Ramon, California. Accessed 2026-10-10.
- 17)Laws 2025, Chapter 259 (SB 1529): ARS 9-461.19, pre-approved plans, Arizona State Legislature. Accessed 2026-10-10.
How these sources were chosen and when the page is reviewed: how we research.