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CSS-019 Minimum Standard Site Plan Requirements for Building & Engineering Applications

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Version 06/25/2024

Site plans are required for most applications at Permit Sonoma (see Notes below). The graphic below depicts the requirements for most Permit Sonoma applications such as Building or Engineering permits.

Planning Permits/Applications: For Planning site plan requirements, visit PJR-129 Site Plan Requirements for Planning Applications.

On this page: Site Plan Example | Requirements | Notes

Site Plan Requirements large


  1. All site plans must be drawn to scale. The site plan will be the same size as the rest of the plans. The site plan shall be drawn to a recognizable architectural/engineering standard. Provide north arrow. Provide additional directions if hard to locate. Partial site plans may be submitted as long as a vicinity map for the property is provided. The vicinity map will show the full parcel including frontage streets and cross reference the area of the partial site plan. Partial site plans must show all required features as listed below. Aerial photos will not be accepted in lieu of the Standard Site Plan. Note: Planning may require a reduced size site plan.
  2. Existing Structures:Show and label all existing structures including pool/spa and retaining walls. Show and dimension all property lines. Identify existing roads, driveways, waterways, and drainage features, septic systems including expansion areas, sub drains, wells and underground utilities. Property lines and dimensions supplied by applicant are for representational purposes only and do not constitute an approval of the location by the County. While not required, it is the Owner’s responsibility to have property lines surveyed.
  3. Proposed Structures/Improvements: Identify all proposed structures including retaining walls. Dimension proposed structures to property lines, setbacks to septic systems, creeks, and other structures. Identify all proposed improvements including driveways, turnarounds, turnouts, areas to be graded, drainage features, power poles, and underground utilities.
  4. If appropriate to specific applications (Project Review, Grading, or Well & Septic) include easements, right-of-ways, building envelopes, and irrigated landscape areas.
  5. Contours (lines denoting elevation of terrain) are required for all building permits subject to a site evaluation. Contours shall be shown and labeled at maximum vertical intervals of 10 feet. See Note #4 below for areas of special concern requiring contour intervals of two feet or less. See Notes #2 and #3 below for exceptions to contour requirements and information regarding who can produce contours.
  6. Fire Safe Standards: Show compliance with Fire Safe Standards required by the Fire Prevention division.
  7. Interior Remodels: Provisions B, C, D, E and F, above, are not applicable to site plans for interior remodels or pool resurfacing. Site plans for interior remodels and pool resurfacing need to show existing buildings, driveways and identification of the building being remodeled or pool being resurfaced. Site plans must otherwise be consistent with provision A above.
  8. Trees: Identify all protected trees 6 inches diameter or larger, their protected perimeter, and whether they are to be retained or removed.


  1. A site plan is required for the following types of applications:
    • New structures
    • Additions which increase the footprint of the structure
    • "As Built" structures
    • Ag Exempt
    • Demolition
    • Encroachment
    • Grading
    • Sanitation Sewer
    • Site Review
    • Septic
    • Well
    • Request for Service
    • Change of Occupancy
    • All Planning Applications – see PJR-129 Site Plan Requirements for Planning Applications
    • Property Reports
    • Ordinance Determinations
    • Interior remodels
    • Pool/Spa
  2. Contour lines are not required on site plans for the following types of applications:
    • Demolition
    • Well
    • Request for Service
    • Property Reports
    • Ordinance Determinations
    • Grading and Septic: contours are required on grading and often on septic plans, but the contours need not be shown on the site plan for these applications
    • Interior remodels
    • Roof or Ground Mounted Solar Systems
    • Temporary Permits
  3. The Business and Professional Code governs who can produce contours and what licenses are required in the State of California. Permit Sonoma will accept contours produced from the following person(s):
    • Property owner (Business and Professions Code section 6744)
    • California licensed surveyor (Business and Professions Code section 8726)
    • California licensed civil engineer (Business and Professions Code sections 6731 and 6731.1)
    • California licensed architect (Business and Professions Code sections 6737 and 5500.1)
  4. The following may require contour intervals of two feet:
    • Installing culverts, drainage pipes, swales, or other small drainage facilities
    • Re-routing of existing or the creation of new swales, interceptor ditches, creeks or drainage pathways
    • Filling of existing swales, ditches, creeks, wetlands or depressions
    • Work within 100 feet of an existing waterway or creek (top of bank)
    • Work in a waterway, creek or drainage swale (installing drainage outlet)
    • Work within the Flood Prone Urban Area or within a 100 year flood plain
    • Construction, paving, or demolition of parking areas