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Mercer Island residential permits, approved faster.
We know how the City's Community Planning & Development team reviews residential projects, including the critical area and shoreline checks that come with island lots, so your remodel, addition or ADU gets to approval with less back and forth.
- Permit specialists who know local code and zoning
- We prepare and submit your application through the City's permit portal
- In-house permit drawings at a fraction of traditional firm costs
- Free revisions until your permit is approved
Call today: (206) 312-2992
Evergreen Permits is a private residential permit service, not part of the City of Mercer Island or any government agency.
Mercer Island's permit specialists
Evergreen Permits is a team of architectural designers and permit specialists helping Mercer Island homeowners, contractors and architects. We do one thing exceptionally well: permits. No upsells, no construction services, just permits done right.
200+
Projects completed
5.0
Star Google rating
10+
Years experience
99%
Approval success rate
What do Mercer Island homeowners worry about most when getting a permit?
We hear the same three questions on almost every project. Here are straight answers.
How long will this take?
The City targets a first review in 2 weeks for non-major building permits and 4 weeks for major ones, after about 3 weeks of intake and routing, then 2 weeks for each later review. These are estimates and can vary. We send a complete package the first time to keep you to as few rounds as possible.
See review times →Will the City send my plans back?
Mapped critical areas, shoreline rules, trees and extra reviews can all add steps, and plan review turns hourly after three rounds. We check your lot's maps first, file complete drawings, answer every comment and revise for free until you're approved.
See what the City looks at →How much are permit fees?
The City builds your fee from your project's value, then adds a 70% plan check fee and a 31% combination permit fee. By its 2026 formula, a $20,000 remodel with trade work comes to about $1,080 before other reviews. We walk you through what applies to you.
Estimate your permit fees →How does Evergreen Permits make permitting easier?
We've permitted projects on the island, including ones that needed critical area and shoreline approvals. Here is how we take the weight off your shoulders.
- We check your lot's maps first for critical areas, shoreline and trees, so surprises come before you file, not after.
- We handle the extra applications when your project needs a Critical Area Review or a shoreline exemption.
- We answer every comment and revise for free until your permit is approved.
Consult
A free call to scope your project and flag what the City will require.
We prepare
Map checks for critical areas and shoreline, plus permit-ready drawings in-house.
Submit & manage
We submit through the City's portal and respond to every review comment.
Get approved
Free revisions until your permit is issued, and support through inspections.
What can Evergreen Permits help you permit in Mercer Island?
From a kitchen remodel to a backyard cottage, we prepare the drawings, submit through the City's portal and manage every review round until you're approved.
What are the building permit requirements in Mercer Island?
What the City looks at on a residential permit, and the items that most often shape a project's scope, timeline and cost.
Critical areas
Some lots have mapped slide, seismic or erosion hazards. These can require a Critical Area Review, and a study if the work disturbs the ground.
Shoreline
Work within 200 feet of Lake Washington needs a shoreline permit or a shoreline exemption, approved before the building permit.
Tree permits
The City says a tree permit is almost always needed. Normal pruning and small trees outside critical areas can be exempt, and trees in critical areas can't be removed outside development.
Layers of review
Beyond the building review, plans can also go to planning, engineering, fire and arborist review, each with its own fee.
ADUs & middle housing
Two ADUs or two middle housing units on most residential lots. An ADU can be 220 to 1,000 sq ft and counts toward a 25% accessory building cap.
Exemptions have limits
Exempt work, like in-kind re-roofing, doesn't stay exempt in flood hazards or critical areas unless it stays within the existing building envelope.
Trade permits
We prepare the main building permit. Your trades handle their own mechanical, plumbing and electrical work, which the City bundles into a combination permit fee.
Three rounds, then hourly
The City charges hourly once plan review goes past three rounds, so a complete first submittal saves money.
Who handles building permits in Mercer Island, and how long does it take?
Who issues it
Planning & Development
City of Mercer Island Community Planning & Development, 9611 SE 36th St. Check status on MyBuildingPermit.com. Phone: (206) 275-7605.
Visit CPD →Review time
2 to 4 weeks
City target for a first review: 2 weeks for non-major building permits and 4 weeks for major ones. Later reviews target 2 weeks.
Review timelines →Watch for
Critical areas
Mapped slide, seismic and erosion areas, and lake-adjacent work, can add critical area or shoreline review.
What the City looks at →Sources: City of Mercer Island Community Planning & Development. Review times are the City's targets, and the City notes that they may vary. Figures reviewed October 2026.
Mercer Island projects we've taken to approval
Re-roof on a lakefront lot
A garage roof replacement that needed more than a roofing permit
Replacing a flat garage roof membrane sounds simple, but this property had mapped critical areas and sat within the Lake Washington shoreline area. The City required a Critical Area Review and a shoreline exemption alongside the building permit. We prepared and filed both applications, with narratives, compliance matrices and plans, and carried the project through review.
Our role: map and code research, three coordinated applications, plans and responses to the City's planning comments.
What do clients say about Evergreen Permits?
Real reviews behind our 5-star Google rating.
“I hired Evergreen Permits to help with the permitting process for my home renovation. They handled the paperwork and guided me through the city requirements, which made the whole process much easier…”
Read full review on Google →“Sara was our main point of contact and was absolutely amazing throughout the entire process. She guided us through multiple permit applications across various projects, always staying accessible and proactive in her communication…”
Read full review on Google →“I am a general contractor and we work with Evergreen on all of our projects. They take great care of our clients, do an excellent job and have very clear communication. We recommend them to everyone!”
Read full review on Google →Why do Mercer Island homeowners choose Evergreen Permits?
We built Evergreen Permits around a simple idea: residential permitting should be easier to understand and more affordable to navigate. Here is what that looks like in practice.
Permit specialists in Mercer Island
Our team specializes in permit assistance in Mercer Island. A project coordinator manages everything for you, so you do not have to worry about a thing.
Free revisions until approval
We support you through every correction and resubmittal, and revisions are free until your permit is approved.
Permits are all we do
No construction services and no upsells. Our only job is getting your permit approved.
Drawings done in-house
Permit-ready drawings and site plans from our own team, at a fraction of the cost of traditional firms.
Simple for you
We guide you through scanning your home with a simple app, then verify every detail remotely, so there is no site visit to schedule.
A track record you can check
200+ projects, 10+ years of experience, a 99% approval success rate and a 5.0 Google rating.
Where are you in your project?
Pick the step that fits. You will leave each one with a clearer picture of what to expect.
Just exploring
Check whether you need a permit
Answer a few questions about your project and see what the City will likely require.
Do I Need a Permit?Planning a budget
Get a fee range in seconds
Enter your ZIP code and project type to see a planning range for your city permit fees.
Try the Permit Cost CalculatorReady to move
Talk to a permit specialist
It is a free consultation. You will leave with an honest picture of what permitting will involve before you commit to anything.
Book a Free ConsultationOr call (206) 312-2992
How much does a building permit cost in Mercer Island?
The City's building permit fee is based on your project's valuation. A plan check fee and a combination permit fee are added on top, and the City publishes every piece.
Get a fee estimate for your project
Our free Permit Cost Calculator gives you a planning range in seconds. Enter your ZIP code and project type.
Fee rules are as published in the City of Mercer Island 2026 Fee Schedule, revised effective August 1, 2026. Only the City sets your final fee, which depends on your valuation, scope and any additional permits. City fees are separate from professional fees for drawings and permit management. Source: City of Mercer Island 2026 Fee Schedule.
Do I need a building permit in Mercer Island?
Decks up to 30 inches above grade, fences up to 6 feet, sheds up to 200 sq ft, retaining walls up to 4 feet and in-kind re-roofing are exempt, but not in critical areas or flood hazards. Interior finish work and in-kind window replacement are exempt too, and most other work needs a permit. See the City's exemption list.
Not sure if your project needs a permit?
Answer a few questions and our free tool will tell you what to expect before you commit to anything.
Mercer Island permit questions, answered
How long does a Mercer Island building permit take?
The City publishes target timelines, and notes they are estimates that may vary. After about 2 weeks of intake screening and 1 week of routing, the first review targets 2 weeks for non-major building permits and 4 weeks for major ones. Second and later reviews target 2 weeks, and preparing the permit for issuance takes about 1 week more. Tree permits target 2 weeks. Projects that need public notice add a 30-day comment period. Complete drawings are the best way to avoid extra rounds, and we handle every correction for you.
Can I build an ADU or DADU on my Mercer Island lot?
Often, yes. On most residential lots the City allows two ADUs, or two middle housing units, and up to four middle housing units within a quarter mile of the light rail station. An ADU can be from 220 to 1,000 square feet, and ADUs count toward the lot's 25% accessory building limit. Lots with more than 100 feet of street frontage can have more than one driveway connection, and others are limited to one curb cut. A feasibility study confirms what your property can support before you pay for full drawings.
Do I need a permit to remove a tree in Mercer Island?
The City says the answer is almost always yes. Normal pruning and maintenance, cutting a small tree outside a critical area or its buffer, pruning limbs that cross your property line, and removing listed invasive or noxious weeds may be allowed without one. Outside of development, removing trees in critical areas or their buffers is not allowed, and the City requires documentation from a qualified arborist. We screen for trees as part of every project.
How do I know if my lot has critical area or shoreline rules?
The City provides a mapping portal where you can search by address or parcel number, and its review comments often cite mapped slide, seismic and erosion areas. Work within 200 feet of the Lake Washington shoreline needs a shoreline permit or a shoreline exemption, approved before the building permit. We check the maps for your lot before we draw anything, so you know early.
Why use a permit service instead of my contractor or doing it myself?
Permits are the only thing we do, so we know what the City asks for and how to answer corrections. Our team specializes in permits, a project coordinator manages everything for you, our drawings are done in-house at a fraction of traditional firm cost, and revisions are free until approval. You stay in control, and your contractor can build from the approved permit.
Do you provide the drawings, or just the paperwork?
Both. Our in-house team produces permit drawings and site plans when your project needs them, and manages the full submission and approval process, so you don't need to coordinate with a separate draftsperson.
Do you work in my Mercer Island neighborhood?
Yes, we serve every part of the island as well as surrounding cities across King County.
Ready to get your permit approved faster?
Tell us about your project and we'll tell you exactly what the City will require, what it will cost and how the review should go.