Detached garage and carport site plans

When a garage or carport needs a permit

Codes file the detached garage and the carport with the other accessory structures on a house lot. Maricopa County, Arizona puts sheds, garages and carports under one set of accessory structure rules, document DD-3012-01, which cites Zoning Ordinance s.1106.2 ^[1]. Whether the garage needs a permit, and so a site plan, turns on a size trigger that each jurisdiction sets for itself:

The Wake County trigger is a dimension, not an area: a narrow carport needs the permit once its length passes 12 feet, whatever its floor area ^[3]. Denver's Residential Permitting Guide, updated September 3, 2026, lists accessory structures, garages and carports among the structures that enter its zoning calculations, so a Denver carport counts toward the lot's zoning figures ^[5].

Where the garage can sit on the lot

Maricopa County's s.1106.2 sets two placement limits for an accessory building: it may not occupy more than 30% of any required yard, and it may not sit nearer than three feet to any side or rear lot line ^[1]. A garage site plan in Maricopa County therefore dimensions the building to each side and rear lot line and shows the required yard it stands in, so the reviewer can check the share it covers ^[1].

Metro Nashville asks the site plan to show the distances to the property lines and to the existing structures, with the easements labeled ^[4]. Its accessory structure permitting instructions rest on Metro Code 17.12.040 to .060 ^[6], and Nashville applies them to sheds and garages alike ^[6]. Because the house and the other existing structures are drawn, the gap between them and the new garage can be read from the plan ^[4].

What the sheet carries

Each item on a garage or carport site plan answers one of the rules above:

• the property lines with their dimensions, drawn to scale ^[7];
• the garage or carport outline with its floor area and its longest dimension, which decide whether the size triggers above apply ^{[2, 3]};
• the distance from the building to each side and rear lot line, and the required yard it occupies ^[1];
• the house and any other existing structures, and every easement, labeled ^[4];
• impervious square footage where the checklist asks for it, the most common extra item on residential checklists, especially in North Carolina, Washington and Georgia; Apex, North Carolina folds additions, alterations and accessory structures into one checklist ^[8].

A garage driveway is drawn as part of the same plan.

The survey under the plan

A detached garage goes through the building permit, so the department's rules on who may draw the site plan apply to it. Metro Nashville does not require that residential site plans be done by a licensed professional, but the plan must be an accurately dimensioned scale drawing ^[7]. Nashville also says that a homeowner's mortgage loan survey works extremely well as the base for a site plan ^[4]. Wendell, North Carolina states that the site plan for a residential structure does not have to be professionally drawn ^[9].

Georgia shows the other end. In Cobb County, before a building permit is issued, the permittee or landowner files a current plan and survey of the property sealed by a registered land surveyor (Development Standards s.103.19.1) ^[10]. There the garage plan starts from the surveyor's sealed survey of the lot ^[10]. The written rules by jurisdiction are collected in where unsealed site plans are accepted, and the difference between the drawings in site plan vs plot plan vs survey.

The studio draws the site plan, not the garage's structure, foundation or drainage. Plans are preliminary, and engineering is by your engineer of record.

When the garage becomes an ADU

California's ADU law treats a garage conversion more lightly than a new building. In California, a local agency may require no more than 4 feet of side and rear setback for an ADU, and no setback at all for an ADU created by converting existing space (Gov. Code 66314(d)(7), cited as of October 10, 2026) ^[11]. An existing garage that stands inside the side or rear setback can therefore be converted where a new ADU on the same spot could be held back from the line ^[11].

In Arizona, municipalities over 75,000 must allow one attached and one detached ADU as a permitted use, may require side or rear setbacks of no more than 5 feet, and may not allow an ADU on a public utility easement without the utility's consent (ARS 9-461.18) ^[12]. The garage site plan shows the easements, which is where that test is made ^[12]. Phoenix asks that an unpermitted structure be legalized before it becomes an ADU ^[13]. The state rules are in ADU laws by state.

Order a garage or carport site plan

Sheds and other small outbuildings are covered in shed site plans, and all residential permit types in permit site plans. What a permit site plan is, in general, is set out in site plan for a permit.

To order, open start a project, choose "Residential: detached garage or carport" as the project type, give the city or county, and attach one file: your survey, or a sketch with the garage's footprint and its distance to the lot lines. The studio reads the jurisdiction's rules and replies by email to scope the plan.