Looking for a retaining wall contractor in Mercer Island, WA? Describe your project once and up to three retaining wall contractors 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. Sloped lots, terraced yards and driveways cut into hillsides keep local wall builders busy.
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
- Permit and engineer: in Washington, taller walls or walls with loads above usually need an engineered design and a permit.
- Drainage: ask how water behind the wall will be drained.
- Property line: a survey avoids building on the neighbor's land.
- Price drivers: height, length, material, access and drainage.
Useful official resources
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ICC: International Code Council
Official information and guidance.
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Call 811
Official information and guidance.
Services available in Mercer Island
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Retaining wall construction
Design and construction of a new retaining wall with drainage.
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Retaining wall repair or replacement
Assessment and repair or replacement of a leaning, bulging or cracked wall.
Frequently asked questions in Mercer Island
How much does a retaining wall cost in Mercer Island, WA?
It depends on height, length, material and access. Describe your project: contractors who serve Mercer Island reply with a quote.
How long does it take?
A small wall can take a few days; engineered walls take longer with permits.
Can a failing wall be repaired?
Sometimes; often a leaning wall must be rebuilt with proper drainage.
Which retaining wall contractors will contact me?
Up to three independent retaining wall contractors 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.