Civil Engineering & Site Design
Site Layout & Site Plans
Buildings, parking, fire access, and utilities fitted within your lot's limits, so planning and building review start from a layout that works.
What is a site plan?
A site layout plan, usually called a site plan, is a scaled drawing of a property that shows property lines, existing and proposed buildings, setbacks, driveways, parking, fire access, utilities and drainage, prepared for planning and building permit applications.
Planners check it against zoning; building and fire departments review grades, access roads, and hydrants. A site plan locates things; it does not detail earthwork. Grading plans then set exact elevations, drainage, and erosion control from the approved layout, often under a separate grading permit.
Deliverables
What's included in a site plan
Scope is set for each project and written into the proposal. A permit-ready site plan typically shows:
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Building placement
Footprints and dimensions, with distances to property lines, easements, required setbacks, and other structures.
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Access & circulation
Driveways, drive aisles, turning paths, and fire apparatus access roads and turnarounds where required.
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Parking & accessibility
Stalls and aisles with required counts, accessible spaces, and the accessible route to entrances.
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Utility connections
Proposed water, sewer or septic, storm drain, power, and telecom routes to existing connection points.
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Grading & drainage
Pad and finished-floor elevations, drainage direction, and room for stormwater treatment areas.
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Survey base
Property lines, easements, existing structures, and contours carried from boundary and topographic surveys.
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Site data table
Lot area, building area, lot coverage, impervious area, and parking provided versus required.
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PDF & CAD files
PDF sheets set up to the agency's checklist, plus CAD files for the design team.
When do you need a site plan?
Start it early, so buildings, parking, and access fit the lot before detailed design begins.
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Commercial and industrial buildings
Planning review checks setbacks, parking, truck circulation, fire access, and stormwater areas.
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Apartments and multifamily housing
A housing project's optional preliminary application, which can lock in the rules in effect when it is filed, must include a site plan (Gov. Code §65941.1).
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Custom homes, additions, and ADUs
House and ADU permits need a site plan showing structures and lot-line distances (CRC §R106.2); tight lots start with a boundary survey.
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Metal buildings and shops
Placing a steel building means setbacks, truck access, pad grades, and room for footings.
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Testing a parcel before you buy
A concept layout shows how much building, parking, and access a parcel can hold.
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Rural sites on septic
The layout reserves room and setbacks for the tank and leach field. See septic system design.
Process
How a site plan comes together
Five steps from the first zoning check to an approved layout.
Confirm rules and checklist
We review zoning, setbacks, parking ratios, fire access, and overlays such as flood or fire hazard zones, and get the agency's submittal checklist.
Assemble the base map
Property lines, easements, existing structures, and contours come from boundary and topographic surveys, or from record data where the agency accepts it.
Test layout options
Alternative layouts place buildings, driveways, parking, and utilities within those limits; you and your architect pick a direction before detailing starts.
Detail and coordinate
The chosen layout is dimensioned and coordinated with grading, utilities, fire access, and stormwater treatment sizing.
Submit and respond
We submit the plan, answer review comments, and revise sheets as needed. The approved layout then feeds grading, improvement plans, and construction staking.
California rules
California requirements for site plans
Zoning, fire access, accessibility, and stormwater rules decide what fits on a site.
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Gov. Code §65850
Zoning sets the layout limits
Cities and counties set building location, height, lot coverage, yards, setbacks and off-street parking by zoning ordinance (Gov. Code §65850). State law overrides some limits: required side and rear setbacks for a new ADU are capped at 4 feet (§66314), and parking minimums are generally barred within a half mile of a major transit stop (§65863.2).
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Cal. Fire Code §503
Fire apparatus access is designed in
A fire apparatus access road, at least 20 feet wide with 13 feet 6 inches of vertical clearance, must reach within 150 feet of every part of a building's first-story exterior walls. Dead ends over 150 feet need an approved turning area. The fire code official sets turning radius and grade, and may extend the 150 feet for fully sprinklered buildings (§503.1.1).
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Cal. Building Code Ch. 11B
Accessible routes and parking
For public buildings, public accommodations, commercial buildings and public housing, Chapter 11B requires at least one accessible route from accessible parking, passenger loading zones, public streets and sidewalks, and transit stops to the entrance they serve (§11B-206.2.1). Accessible parking goes on the shortest accessible route to an accessible entrance (§11B-208.3.1). Chapter 11A applies to covered multifamily housing.
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Order WQ 2013-0001-DWQ
Stormwater design starts at layout
In cities and counties under the statewide Small MS4 permit, still in effect as of September 2026, most projects creating or replacing 5,000 square feet or more of impervious surface must use Low Impact Development: site design, source control, runoff reduction and treatment. Treatment areas belong on the first layout. Phase I areas and Central Coast agencies follow regional requirements.
Requirements vary by city and county. Each agency sets its own application checklist (Gov. Code §65940), and some hold a separate site plan or design review before building plan check. Driveway approaches need a city, county, or Caltrans encroachment permit.
Sources & references
- 2025 California Building Code, Chapter 1: Administration (§107.2.6 Site plan) (ICC Digital Codes, free public viewer)
- 2025 California Fire Code, Chapter 5: Fire Service Features (§503 Fire apparatus access roads) (ICC Digital Codes, free public viewer)
- Government Code §65850, zoning regulations (California Legislative Information)
- 2025 California Building Code, Chapter 11B: Accessibility to Public Buildings, Public Accommodations, Commercial Buildings and Public Housing (California Building Standards Commission)
- Phase II Small MS4 General Permit, Order WQ 2013-0001-DWQ (conformed) (State Water Resources Control Board)
Last reviewed .
Site plan FAQs
Is a plot plan the same as a site plan?
A plot plan and a site plan are usually the same drawing for a house permit; the California Residential Code titles its requirement "Site Plan or Plot Plan" (§R106.2). Some agencies reserve "site plan" or "civil site plan" for commercial, multifamily, or multi-building sites, where parking, circulation, utilities, and drainage need more detail.
What needs to be on a site plan for a building permit?
A site plan for a California building permit shows, at minimum, the size and location of new and existing structures and their distances from lot lines (California Residential Code §R106.2 for houses). For buildings under the California Building Code, it must also be drawn to scale and show established street grades, proposed finished grades, and any flood hazard areas (§107.2.6). Planning checklists usually add easements, setbacks, parking, driveways, fire access, utilities, and a site data table, and each city and county sets its own list.
Do I need a survey for a site plan?
A site plan needs a boundary survey in some cases, depending on the code and the agency. Under the California Building Code, the site plan must be drawn in accordance with an accurate boundary line survey (§107.2.6). The California Residential Code's site plan section for houses and most ADUs (§R106.2) has no survey requirement, so the agency decides whether an existing survey, recorded map, or owner measurements will do. Work close to property lines often calls for boundary and topographic surveys.
Who can prepare a site plan in California?
A site plan in California can be prepared by different people, depending on the project and the agency. Civil engineering plans must be prepared by or under the responsible charge of a licensed civil engineer and signed and sealed (Bus. & Prof. Code §6735); architects' practice includes site planning (§5500.1); and some agencies accept owner-drawn plot plans for small residential work. Locating property lines in the field is boundary surveying, limited to licensed land surveyors and civil engineers licensed before 1982 (§8731).
What affects the cost and schedule of a site plan?
The cost and schedule of a site plan depend on project type and size, whether current boundary and topographic survey data exist, zoning and overlay constraints, fire access and accessibility requirements, the number of layout options studied, and how many agency review rounds it takes. Share the address, what you plan to build, and your agency's checklist; the proposal then sets scope and timing.