Looking for a civil engineer in Mercer Island, WA? Describe your project once and up to five licensed civil engineers who work in Mercer Island and King County get back to you with a quote. It's free and there is no obligation.
Mercer Island is home to about 25,302 people (2024 Census Bureau estimate), a shrinking community (−1.8% since 2020). With 3,964 people per sq mi, it is a densely built-up area. New homes, commercial buildings and subdivisions here go through site plan review, where a sealed civil plan is often required.
Mercer Island at a glance
- Population (Census Bureau estimate, 2024)
- 25,302 (−1.8% since 2020)
- Rank in Washington
- 45th of 281 cities and towns
- Land area
- 6.4 sq mi
- Population density
- 3,964 people per sq mi (densely built-up)
- Type
- City (Mercer Island city)
- Main county
- King County
What to check before hiring in Mercer Island
- License: in Washington, site, grading and drainage plans are sealed by a Professional Engineer licensed by the state board.
- Survey: have a boundary and topographic survey ready, or ask the engineer to coordinate one.
- Local rules: stormwater standards differ between cities and counties; the engineer designs to the rules where the site is.
- Price drivers: site size, slope, utilities, stormwater requirements and review rounds.
Useful official resources
-
NCEES: state licensing boards
Find your state board to check an engineer's license.
-
EPA: construction stormwater
Federal stormwater rules for construction sites.
Services available in Mercer Island
-
Site plan, grading and utilities
Civil site plan with grading, utilities and access, sealed by a licensed engineer for the permit.
-
Stormwater and drainage design
Drainage calculations and stormwater management design required by the city, county or state.
Frequently asked questions in Mercer Island
How much does a site plan cost in Mercer Island, WA?
It depends on the site, the project and the local requirements. Describe your project: engineers who serve Mercer Island send a proposal.
How long does it take?
Design often takes a few weeks, then the review by the city or county adds time.
Can the engineer handle the permit review?
Most civil engineers respond to review comments and resubmit the plans for you.
Which licensed civil engineers will contact me?
Up to five independent licensed civil engineers who serve Mercer Island and the surrounding area, chosen for the service you need. Your details are shared only with your consent.
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2024) and Gazetteer Files (public domain), imported on 10/31/2026. Figures describe the incorporated place or county as published; they are shown for information only.