Mercer Island, WA Building Permits: Review Times, Process and Costs
Mercer Island, WA building permit timeline: Initial plan review takes approximately 3 days. Contact the building department for current processing times.
Building permit review in Mercer Island, WA takes approximately 3 days for initial plan review. This page covers review timelines, required permits, costs, and how to speed up the process.
Mercer Island Plan Review Timeline
The latest official review timelines for building permits in Mercer Island, WA, can be found on the city’s Community and Planning Department (CPD) website, not the above link, but the most relevant page is as follows:
- First Review – Major Building Permits (Type 3): 4 weeks
- First Review – Non-Major Building Permits (Type 1): 2 weeks
- First Review – Site Development Permits (Type 1): 2 weeks
- Second and Subsequent Reviews: 2 weeks
- Prepare Approved Permit for Issuance: 1 week
- Revisions: 2–3 weeks
Additional timing details:
- Intake Screenings: 2 weeks (once all documents provided)
- Routing: 1 week (once deemed complete)
- Public Notice: Some permits require a 30-day public comment period; plan review can occur concurrently but permit cannot be issued until comment period ends
- Other permits: Fire (3 weeks), Mechanical/Electrical/Plumbing (2 weeks), Side Sewer/Fuel Tank/Field Inspection (3 days), Tree Permits (2 weeks, if not related to building projects)
These times are targets and may vary depending on workload, completeness of application, and other factors.
If you specifically needed the time for "plan check process" as indicated, the above data refers to the review and processing of submitted plans.
Note: The link you provided (letstalk.mercergov.org/community-development-projects) does not contain review timeline information; this data was sourced from the CPD’s official "Review Timelines" page.
Last verified: June 2025 | Source: Mercer Island Building Department
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What Building Permits Do You Need in Mercer Island?
Mercer Island requires permits for most construction activity. The type of permit depends on your project scope.
Commercial Permits
- New commercial construction: full plan review with the longest timeline
- Tenant improvements and interior buildouts: plan review for structural, electrical, plumbing, and mechanical changes
- Change of use: required when converting building use (for example, retail to restaurant)
- Shell and core: separate from tenant improvement permits
Residential Permits
- New home construction: full plan review including structural, mechanical, electrical, and plumbing
- Additions and remodels: required when modifying structure or adding square footage
- Decks, pools, fences: separate permits with typically faster review
Trade Permits
Individual trade permits are typically required for electrical, plumbing, mechanical (HVAC), and fire sprinkler work.
How the Mercer Island Permit Review Process Works
Step 1: Application Submission
Submit your permit application through the Mercer Island building department. Applications are reviewed for completeness before being assigned to a plan reviewer.
Step 2: Plan Review
The city reviews your submitted plans for building code compliance, structural integrity, fire safety, energy code, and ADA accessibility. Commercial projects are reviewed by multiple departments at the same time.
Step 3: Corrections and Resubmittal
If the city issues correction comments, you will need to revise your plans and resubmit. Each correction cycle adds another review period. Most commercial projects go through 2 to 3 correction cycles.
Step 4: Permit Issuance
Once all review departments approve your plans, the building permit is issued. Schedule inspections as work progresses.
Note: These timelines reflect general review periods. Large or complex projects may take longer. Request a quote from Permit Place for a project-specific estimate, or get an instant due diligence report from PermitNow.io.
Mercer Island Building Permit Costs
Permit fees in Mercer Island vary based on project type and valuation.
Commercial
- Tenant improvements: $500 to $5,000+
- New commercial construction: $2,000 to $25,000+ (based on valuation)
- Plan review fee: typically 50-65% of the building permit fee
Residential
- Small projects (decks, pools, fences): $50 to $300
- Home additions and remodels: $200 to $2,000+
- New home construction: $1,000 to $10,000+ (based on valuation)
For a detailed permit cost breakdown specific to your project, get a free due diligence report from PermitNow.io.
Trade Permits
- Electrical: $50 to $500
- Plumbing: $50 to $500
- Mechanical: $50 to $500
Fee ranges are estimates. Actual fees depend on project valuation and scope. Contact the Mercer Island building department or Permit Place for exact costs.
Mercer Island Building Department
Mercer Island Building Department
- Website: letstalk.mercergov.org/community-development-projects
- City Website: letstalk.mercergov.org
Frequently Asked Questions About Mercer Island Building Permits
How long does it take to get a building permit in Mercer Island?
Plan review in Mercer Island, WA takes approximately 3 days for the initial review cycle. Projects that receive correction comments will need additional review cycles, each adding time to the total. Most commercial projects go through at least two review cycles before approval.
What is the difference between residential and commercial permit review in Mercer Island?
Commercial projects in Mercer Island require review by multiple departments (building, fire, public works, and sometimes health), which adds time. Residential projects typically involve fewer review disciplines and can be processed faster. Tenant improvements fall between the two depending on scope.
Can I speed up the permit process in Mercer Island?
The most effective way to speed up the permit process in Mercer Island is to submit complete, code-compliant plans on the first attempt. This reduces correction cycles, which are the primary cause of delays. Permit Place helps ensure your application is complete before submission.
Do I need a permit for a tenant improvement in Mercer Island?
Yes. Most interior buildouts in Mercer Island that involve structural changes, electrical work, plumbing, or HVAC modifications require a building permit. Simple cosmetic changes (paint, flooring, non-structural work) typically do not require a permit.
How much does a building permit cost in Mercer Island?
Permit fees in Mercer Island are calculated based on project valuation and type. Commercial projects typically pay $500 to $25,000+ in total permit and plan review fees. The exact cost depends on project scope, square footage, and any additional trade permits required.
Can a permit expediter help with my Mercer Island project?
Yes. Permit Place expedites building permits in Mercer Island and 600+ other jurisdictions. We handle everything from application preparation through plan review, corrections, and permit issuance. Our clients typically get permits faster because we submit complete applications that reduce correction cycles.
What building permits do I need in Mercer Island, WA?
Most construction in Mercer Island requires a building permit. This includes new construction, tenant improvements, change of use, additions, and major renovations. Separate trade permits for electrical, plumbing, mechanical, and fire protection are also typically required. For a project-specific permit requirements report, use PermitNow.io.
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