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Seattle Site Plan – $89, 24‑Hour Delivery, Pass SDCI Review

Permit‑ready residential and ADU site plans for Seattle homeowners, contractors, and builders. You submit the address. We deliver a PDF that passes. No learning curve.

Seattle’s Department of Construction and Inspections (SDCI) enforces site plan requirements under Tip 103, Tip 103A, and Tip 103B (Environmentally Critical Areas). The most common permit delays do not come from major design flaws. They come from missing details on the site plan – omitted property line dimensions, unlabeled easements, incorrect lot coverage calculations, or a missing flood note.

We draft reviewer‑ready site plans in 24 hours. Upload your address. We pull parcel data, verify property lines, calculate lot coverage, add required notes, and deliver a PDF ready to attach to your permit application.

  • 24‑hour turnaround for most residential plans
  • Fixed pricing – $89 to $249
  • Free revisions if SDCI asks for changes
Order Your Seattle Site Plan Now – Starts at $89

Why Seattle Permits Get Delayed (And How We Prevent It)

SDCI reviews site plans against the Seattle Municipal Code (SMC), Tip 103 requirements, and – for properties with slopes, wetlands, or streams – the Environmentally Critical Areas (ECA) ordinance (SMC 25.09). Reviewers reject plans for the same small omissions again and again:

  • Property lines not clearly shown and labeled. SDCI requires property boundaries on all floor plans, roof plans, and elevation drawings.

  • Lot coverage calculation missing or incorrect. The limit varies: 35% for lots ≥5,000 sq ft; for lots under 5,000 sq ft, 1,000 sq ft + 15% of lot area (capped at 50%).

  • Easements omitted or improperly labeled. Tip 103 requires legal descriptions of the property including all easements.

  • ECA site not properly documented. Properties on steep slopes, near wetlands, or in riparian corridors need a surveyed site plan stamped by a Washington licensed surveyor with ECA boundaries and buffers shown.

  • Drainage plan missing. If your project adds 5,000 sq ft or more of new plus replaced hard surface, a licensed civil engineer must prepare drainage plans.

  • ADU size or placement exceeds code. DADUs are limited to 1,000 sq ft in neighborhood residential zones, with rear yard coverage capped at 40% for accessory structures.

  • SEPA checklist omitted. Projects above threshold may require an Environmental Checklist and SEPA review.

We include everything on the SDCI checklist before you submit – so you avoid the resubmission queue and the hidden costs of a correction cycle.

What We Include – And Why It Matters to SDCI Reviewers

You do not need to learn Tip 103 or the Seattle Municipal Code. We do. Every Seattle site plan we deliver includes:

 
 
Element Why SDCI Reviewers Check It
Property lines with dimensions Tip 103 requires property lines labeled on all drawings. SDCI will reject if they’re missing.
Lot coverage calculation Seattle enforces strict limits: 35% for lots ≥5,000 sq ft; 1,000 sq ft + 15% for smaller lots (max 50%).
Easements with legal descriptions Required under Tip 103. “Utility easement” alone is insufficient.
ECA boundaries and buffers For properties in critical areas, SMC 25.09 requires a surveyed site plan stamped by a Washington licensed surveyor.
Drainage and stormwater notes Required if hard surface exceeds 5,000 sq ft – must be prepared by a licensed civil engineer.
ADU/DADU size and rear yard coverage DADU: max 1,000 sq ft (NR zones), 650 sq ft (lowrise). Rear yard coverage: 40% max for accessory structures.
Tree protection notes Seattle enforces tree protection regulations; missing notes trigger corrections.
SEPA checklist (if applicable) May be required for projects above SEPA thresholds. We advise if needed.
North arrow and engineering scale Required on every sheet – SDCI will reject without them.
King County Assessor parcel number Mandatory for all site plans.

You do not need to understand any of this. We handle it.

What SDCI Reviewers Commonly Flag – Real Correction Examples

Here is what actual correction letters from Seattle SDCI look like – and how we prevent them:

“Please clearly show and label the property lines on the site plan, all floor plans, roof plan and elevation drawings.”

We include property lines with dimensions on every sheet. SDCI will not review a site plan submitted as a single sheet; it must be part of a complete plan set.

“Lot coverage calculation missing or does not match SMC 23.44.010.”

We calculate lot coverage against Seattle’s formula – 35% for lots ≥5,000 sq ft, or 1,000 sq ft + 15% of lot area for smaller lots – and show the math on your plan.

“Legal description of property not included. Easement not shown with instrument number.”

We add the legal description and recorded easement references from King County records, per Tip 103 requirements.

“Site contains environmentally critical area (ECA) – surveyed site plan required per SMC 25.09.”

If your property is in an ECA (steep slope, wetland, riparian corridor), we advise you upfront. A Washington licensed surveyor must stamp the plan. We coordinate this for you.

“Drainage plan missing. More than 5,000 sq ft of new plus replaced hard surface requires DWC and CSC/SOIL plans by a licensed civil engineer.”

We flag this before you order. If your project exceeds the threshold, we recommend an engineer – or help you find one.

Seattle Site Plan Pricing – Fixed, No Surprises

Packages Price
Basic Site Plan (setbacks, property lines, existing/proposed) $89
Enhanced Plan (+ FAR, flood BFE, utility easements, Seattle compliance) $149
Premium Plan (+ grading/drainage, ADU/DADU compliance, lot coverage, complex sites) $249+

✅ Revisions included free if the city asks for changes.
✅ 24‑hour turnaround for most residential plans.

Why Seattle Is Different – What You Need to Know (And What We Handle)

  1. Seattle’s permit requirements go beyond what most homeowners expect. Here are the real pain points that cause delays:

    • Tip 103 is mandatory. All site plans must meet the requirements in SDCI Tip 103 (Site Plan Guidelines and Requirements). Missing information = automatic rejection.

    • Lot coverage is strictly enforced and formula‑based. Many homeowners assume they can use their entire lot. Seattle caps coverage at 35% for most lots; smaller lots get a different formula (1,000 sq ft + 15%).

    • ECAs require a surveyed plan. If your property is in a critical area (steep slopes, wetlands, riparian corridors), you need a site plan stamped by a Washington licensed surveyor. We coordinate this for you.

    • ADU/DADU rules are not intuitive. DADU size is capped at 1,000 sq ft in neighborhood residential zones (650 sq ft in lowrise zones). Rear yard coverage for accessory structures is limited to 40%.

    • Stormwater thresholds trigger engineer requirements. Adding 5,000 sq ft or more of hard surface requires drainage plans by a licensed civil engineer. We flag this early.

    • A pre‑application site visit (PASV) may be required. New construction or ECA projects often need a PASV before permit submission. We help you understand what’s needed.

    You do not need to learn any of this. We do the research, and you get a plan that passes.

Local Permit Story – Seattle DADU Rejected Twice, Fixed in 24 Hours

Project: Detached Accessory Dwelling Unit (DADU) in a single‑family zone in North Seattle

Problem: The homeowner attempted to use a national online service. The first site plan omitted the legal description and easement references. The second plan (after the homeowner tried to fix it) still showed the DADU size exceeding the 1,000 sq ft limit for neighborhood residential zones and did not include the required rear yard coverage calculation.

Reviewer Comments (actual):

  • “Legal description of property not included. Easement not shown with instrument number.”

  • “DADU exceeds maximum gross floor area of 1,000 sq ft per SMC 23.44.”

  • “Rear yard coverage calculation missing. Accessory structures limited to 40% of rear yard area.”

  • “Flood zone reference missing – FEMA panel number required.”

What we changed:

  • Added the legal description and recorded easement book/page number from King County records

  • Reduced the DADU footprint to 1,000 sq ft (per code)

  • Added rear yard coverage calculation (40% limit for accessory structures)

  • Added FEMA panel number (Zone X, Panel 5303300175C) and flood note

  • Included required ADU notes: size, height, setbacks, parking

Outcome: The homeowner resubmitted our plan. SDCI approved it on the next review cycle. Total delay saved: 5 weeks. The homeowner avoided additional application fees and a second pre‑application site visit.

Why Homeowners Choose SitePlans.us for Seattle Permits

    • Speed – Most plans delivered in 24 hours. No waiting weeks for a local drafter.

    • Fixed pricing – $89–$249, no hourly surprises.

    • Free revisions – If SDCI asks for changes, we revise at no cost.

    • Permit‑focused drafting – We start with SDCI’s Tip 103 checklist, not a blank screen.

    • ADU/DADU‑ready – We verify size limits, rear yard coverage, and setbacks before you submit.

    • ECA‑aware – We identify critical area issues early and coordinate surveyed plans when needed.

    • No survey required for most projects – We use recorded plats, deeds, and King County GIS data.

FAQ – For People Ready to Order

Most residential plans are delivered within 24 hours. Complex projects (ECAs, large hard surface, subdivisions) may take longer – we will quote you.

We revise for free. Send us the correction letter through the Seattle Services Portal, and we update the plan at no charge.

Not for most projects. We use recorded plats, deeds, and county GIS data. If your property is in an ECA (steep slope, wetland, riparian corridor), you will need a surveyed plan stamped by a Washington licensed surveyor. We will tell you upfront and can coordinate this for you.

Yes. We have done hundreds of residential site plans for Seattle homeowners and contractors. For DADUs, we verify size limits (max 1,000 sq ft in NR zones), rear yard coverage (40% max), and required setbacks before you submit.

Yes. Every Seattle plan includes the legal description, recorded easement references, and FEMA flood panel number per Tip 103 requirements.

We will identify this upfront. SMC 25.09 requires a surveyed site plan stamped by a Washington licensed surveyor. We can coordinate this for you or advise you on next steps.

Click the button below, enter your property address, and complete checkout. We do the rest.

Order Your SeatlleSite Plan – Basic $89

Seattle Authority & Local Resources

    • Seattle Department of Construction and Inspections (SDCI) – 700 5th Ave, Seattle, WA 98104. Call (206) 684‑8850. Website: seattle.gov/sdci

    • Seattle Services Portal – Online permit application and plan review system: cosaccela.seattle.gov/Portal

    • Tip 103 – Site Plan Guidelines and Requirements – Mandatory for all site plans.

    • Tip 103B – Environmentally Critical Area Site Plan Requirements – Required for ECA properties.

    • Seattle Municipal Code (SMC) 23.44 – Lot Coverage – 35% for lots ≥5,000 sq ft; 1,000 sq ft + 15% for smaller lots.

    • SMC 23.44 – DADU Requirements – 1,000 sq ft max in NR zones, 650 sq ft in lowrise zones.

    • SMC 25.09 – Environmentally Critical Areas – Surveyed site plan required.

    • FEMA Flood Map Service Center – Official flood zone determinations: msc.fema.gov

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Ready to Submit Your Seattle Permit? Stop Researching. Start Ordering.

Give your address. We will do the technical work – property lines, legal descriptions, lot coverage, easements, ECA requirements, and flood notes. You will receive a PDF that SDCI can approve.
Order Your Seattle Site Plan – Starting Basic $89

Based on Seattle Municipal Code, SDCI Tip 103, Tip 103B, and SMC 25.09 (Environmentally Critical Areas) as of June 2026. We keep up with the rules so you do not have to.

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