A Seattle residential site plan shows the complete property from above, including the lot boundaries, existing structures, proposed construction, dimensions, setbacks, driveways, alleys, paved areas, trees and other relevant site conditions.

The drawing helps the Seattle Department of Construction and Inspections understand exactly where the proposed project will be located and how it relates to the rest of the property.

Send us your property address, survey or previous plan if available, photographs, project dimensions and a sketch showing the intended location. We can organise that information into a clean residential site plan for your permit package.

Why Seattle Permit Applications Need a Site Plan

Seattle SDCI describes a site plan as an accurate drawing or map showing the size and shape of a property and the location of natural and constructed features.

SDCI’s current permit-process guidance instructs applicants to include a site plan meeting the requirements of Tip 103 for a preliminary or simple site plan, depending on the permit type.

The site plan may help reviewers assess:

• Property boundaries and lot dimensions
• Placement of existing buildings
• Location and size of proposed construction
• Distances to property lines
• Building separation
• Lot coverage
• Driveway and alley access
• Parking and paved areas
• Known easements
• Trees and tree-protection requirements
• Environmentally critical areas
• Grading and drainage conditions

A clear site plan does not guarantee permit approval, but it gives the reviewer a measurable drawing from which to evaluate the proposal.

Official source: Seattle SDCI Tip 103 — Site Plan Guidelines and Requirements .

What Should a Seattle Site Plan Include?

The exact requirements depend on the permit and property conditions. A residential Seattle site plan commonly includes the following information.

Property identification

• Property address
• Legal description
• King County Assessor parcel number when required
• Project title and description
• Preparation or revision date

Property boundaries and lot dimensions

The complete legal property should be shown, including:

• Front property line
• Side property lines
• Rear property line
• Angled or curved boundary sections
• Available boundary dimensions
• Street and alley frontages

Do not assume that a fence, hedge, curb or edge of lawn follows the legal boundary.

Existing buildings and improvements

Relevant existing features may include:

• Main dwelling
• Attached or detached garage
• Shed or accessory structure
• Deck, porch or patio
• Swimming pool
• Retaining wall or rockery
• Driveway and parking area
• Walkways and sidewalks
• Fences and gates
• Roof overhangs

Proposed construction

The proposed project should be clearly labelled and visually different from existing improvements.

The drawing may need to show:

• Complete proposed footprint
• Overall length and width
• Connection to the existing house
• Stairs and landings
• Deck or porch areas
• Roof overhangs
• Supporting posts
• New paving or driveway areas
• Structures proposed for removal

Setback and separation dimensions

The plan should show measurable distances from the proposed project to:

• Front property line
• Both side property lines
• Rear property line
• Existing house
• Other accessory structures
• Known easements
• Street or alley where relevant

Access and paved areas

• Driveways
• Parking areas
• Alleys
• Vehicle access
• Sidewalks
• Walkways
• Existing and proposed paving

Orientation and scale

• North arrow
• Written drawing scale
• Graphic scale bar when useful
• Street names
• Clear existing and proposed legend

Additional Seattle site information

Depending on the property and permit, SDCI may also request:

• Tree locations and tree-protection areas
• Contour lines or ground elevations
• Environmentally critical area information
• Drainage patterns and stormwater features
• Utility information
• Public right-of-way features
• Lot-coverage calculations
• Impervious-area calculations
• Retaining walls and slope information

Some of these items require information from a licensed surveyor, engineer, arborist or another qualified professional.

Common Seattle Projects That May Need a Site Plan

House Additions and Remodels

A Seattle addition site plan commonly shows the entire existing house, the proposed expansion, lot boundaries, setback dimensions, existing accessory structures and changes to paved or landscaped areas.

SDCI states that an addition or remodel requires a construction addition or alteration permit. Smaller projects may qualify for a Subject-to-Field-Inspection permit.

The combined footprint of structures, covered areas and decks at least 36 inches above the ground may also affect the applicable lot-coverage calculation.

Official source: Seattle SDCI — House Additions and Remodels .

Garage Site Plans

A Seattle garage site plan may need to show:

• Garage length and width
• Distance to property lines
• Distance to the existing house
• Driveway or alley access
• Garage-door orientation
• New paving
• Known easements

SDCI says most new and remodelled garages require a Subject-to-Field-Inspection permit when the garage is no more than 750 square feet, is single-story without a roof deck, has beams spanning no more than 14 feet and is not on property containing an environmentally critical area.

Projects outside those limits may require a different permit path or additional documentation.

Official source: Seattle SDCI — Garages .

Deck Site Plans

A Seattle deck plan should clearly identify:

• Deck footprint
• Deck height above grade
• Connection to the house
• Stairs and landings
• Distance to property lines
• Relationship to existing structures

SDCI requires a construction permit when a deck is more than 18 inches above the ground or is a roof deck.

In Seattle’s neighborhood residential zones, decks more than 36 inches above the ground count toward lot coverage. Decks more than 18 inches above the ground also have placement limitations near front, side and rear property lines.

Official source: Seattle SDCI — Decks .

Fence Site Plans

A fence drawing may show the complete proposed alignment, gates, fence height, streets, alleys, driveways, property boundaries and any retaining-wall relationship.

Seattle generally does not require a construction permit for a fence no more than 8 feet high when it does not contain masonry or concrete elements over 6 feet.

A construction permit is required when the fence is located in a flood-prone area. Taller fences requiring a permit need scaled plans, including a site plan and section or detail drawings.

Official source: Seattle SDCI — Fences .

Shed Site Plans

A shed may be small, but zoning restrictions concerning its height, location, lot coverage and distance from property lines can still apply.

Seattle may exempt a small shed from a construction permit when it satisfies all listed SDCI exemption criteria, including a roof footprint of no more than 120 square feet. Larger or nonqualifying sheds require a permit, and many are processed through the Subject-to-Field-Inspection route.

Even a permit-exempt shed must comply with applicable land-use and placement requirements.

Read our related guide: Plot Plan for a Shed Permit in Seattle .

Official source: Seattle SDCI — Sheds .

Retaining Walls and Rockeries

A retaining-wall site plan may need to show the wall location, complete length, wall height, property-line distance, adjoining structures, slope conditions and related grading.

SDCI says a construction permit is not required when all three of the following conditions are met:

• The wall or rockery is no more than 4 feet high, measured from the bottom of the footing to the top of the wall
• The property does not contain an environmentally critical area
• The work will not damage adjoining properties or structures

A permit is required when the project does not satisfy all three conditions.

Official source: Seattle SDCI — Retaining Walls and Rockeries .

Paving, Driveways and Grading

A paving or driveway site plan may show:

• Existing and proposed paved areas
• Driveway width
• Parking spaces
• Street and sidewalk relationship
• Garage or carport access
• Drainage direction
• Ground-disturbance area
• Property boundaries

SDCI states that a grading permit is required when 750 square feet or more of paving is added or replaced.

Additional review may apply when the work changes grade, affects drainage, disturbs a steep slope or is located in an environmentally critical area.

Official sources: Seattle SDCI — Paving and Seattle SDCI — Grading Permits .

Environmentally Critical Areas

Seattle properties can be affected by steep slopes, landslide-prone areas, wetlands, shoreline areas, flood-prone areas and other environmentally critical areas.

A basic drafted site plan may not be sufficient when these conditions apply.

SDCI may require additional documents such as:

• A topographic survey
• An environmentally critical area site plan
• A geotechnical report
• Drainage information
• Tree-protection information
• An exemption or other land-use approval

SDCI currently requires a Pre-Application Site Visit for many land-use and new-construction applications, grading applications, projects with more than 750 square feet of ground disturbance on non-ECA sites, shoreline or wetland projects, and certain work on properties with mapped steep slopes.

The resulting report may identify drainage patterns, trees, existing structures, street curbs, environmentally critical areas and potential property-line impacts.

Official source: Seattle SDCI — How to Get a Permit .

Site Plan vs Survey in Seattle

A drafted site plan and a licensed survey are not the same.

Seattle may require a current survey or Washington-licensed professional when:

• Property boundaries are uncertain
• The project is close to a property line
• Accurate ground elevations are required
• The site contains certain environmentally critical areas
• There is a boundary disagreement
• SDCI specifically requests certified information

Read Seattle Plot Plan vs Survey for a fuller comparison.

How Our Seattle Site Plan Service Works

1. Place your order. Select the site-plan option that fits the requested level of detail.
2. Provide the property address. Available mapping, aerial and property information can be reviewed.
3. Upload your documents. Send an existing survey, plat, previous site plan or permit comments when available.
4. Describe the project. Provide the proposed project type, dimensions and location.
5. Send photographs and a sketch. Mark where the project will be placed.
6. Review the completed drawing. Check the project dimensions, labels and proposed location.
7. Request reasonable edits. Site-plan revisions can be made when a reviewer requests drawing corrections.

The usefulness and accuracy of a remotely prepared plan depend on the quality of the surveys, property records, dimensions, photographs and project information supplied.

Common Seattle Site Plan Problems

• Incorrect or missing property address
• No legal description or parcel information when requested
• Incomplete property boundaries
• Missing lot dimensions
• No north arrow
• No drawing scale
• Existing house or accessory structures omitted
• Proposed work not clearly labelled
• Project dimensions missing
• Distances to property lines missing
• Distance between buildings not shown
• Street, alley or driveway information omitted
• Tree information missing where relevant
• Known easements ignored
• Slope, drainage or ECA conditions omitted
• The site plan does not match the other permit documents
• A blurry screenshot submitted instead of a clear PDF

A complete drawing cannot eliminate every review comment, but it can reduce corrections caused by missing or unclear site information.

Frequently Asked Questions

Do I need a site plan for a Seattle residential permit?

Many Seattle construction and land-use applications require a site plan meeting SDCI Tip 103. The exact plan type and detail depend on the project.

Can you prepare a Seattle addition site plan?

Yes. We can show the existing house, proposed addition, property boundaries, available setbacks, accessory structures, driveways and other relevant site details.

Can you prepare a garage site plan?

Yes. A garage plan can show the garage footprint, driveway or alley access, property-line distances, separation from the house and other relevant improvements.

Can you prepare a deck site plan?

Yes. A deck plan can show its footprint, stairs, connection to the house, dimensions and distances to the property lines. Structural deck plans or engineering are separate when required.

Do all fences need a Seattle permit?

No. Seattle generally exempts fences no more than 8 feet high when they do not contain masonry or concrete elements over 6 feet. Flood-prone locations and taller fences can require permits.

Can I use an old survey or site plan?

An existing survey, recorded plat or previous approved plan can be useful source information. It should be checked against the current property and proposed work.

Are your Seattle plans stamped?

No. USA Site Plans provides residential drafting services. Licensed surveying, architectural seals, structural engineering, geotechnical reports, drainage design and stamped ECA plans must be obtained separately when required.

Can a Seattle site plan be prepared online?

Many straightforward residential plans can be prepared remotely using an existing survey or plat, property records, aerial imagery, photographs and measurements supplied by the customer.

Will the site plan guarantee Seattle permit approval?

No. SDCI controls approval and may request corrections, a licensed survey, engineering, drainage information, tree documentation or other supporting materials.

Official Seattle Sources

• Seattle SDCI Tip 103 — Site Plan Guidelines and Requirements
• Seattle SDCI — How to Get a Permit
• Seattle SDCI — House Additions and Remodels
• Seattle SDCI — Garages
• Seattle SDCI — Decks
• Seattle SDCI — Fences
• Seattle SDCI — Sheds
• Seattle SDCI — Retaining Walls and Rockeries
• Seattle SDCI — Paving

Disclaimer: This article provides general educational information and is not legal, surveying, engineering, architectural, geotechnical, zoning or permitting advice. Seattle requirements vary according to the property, project, zoning, environmentally critical areas and current regulations. SDCI notes that some guidance documents may not reflect every recent regulatory change, so requirements should be confirmed for the specific application. A drafted site plan does not establish legal property boundaries or replace licensed professional documentation when required.