Looking for a drainage contractor in Black Diamond, WA? Describe your project once and up to five drainage contractors who work in Black Diamond and King County get back to you with a quote. It's free and there is no obligation.
Black Diamond is home to about 6,787 people (2024 Census Bureau estimate), a growing community (+44.6% since 2020). With 1,029 people per sq mi, it is a semi-rural area. Heavy rains, clay soils and flat lots are common causes of soggy yards here.
Black Diamond at a glance
- Population (Census Bureau estimate, 2024)
- 6,787 (+44.6% since 2020)
- Rank in Washington
- 112th of 281 cities and towns
- Land area
- 6.6 sq mi
- Population density
- 1,029 people per sq mi (semi-rural)
- Type
- City (Black Diamond city)
- Main county
- King County
What to check before hiring in Black Diamond
- Call 811: utilities must be marked before digging.
- Outlet: ask where the water will go; local rules limit discharges toward neighbors and streets.
- Permits: in Washington, large grading jobs may need a permit from the city or county.
- Price drivers: length of drain, depth, outlet, and lawn or hardscape restoration.
Useful official resources
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Call 811
Official information and guidance.
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EPA: green infrastructure for homeowners
Official information and guidance.
Services available in Black Diamond
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French drain or yard drain
French drain, catch basins or channel drains to move water away from the problem area.
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Grading and regrading
Regrading the soil so that water flows away from the house.
Frequently asked questions in Black Diamond
How much does yard drainage cost in Black Diamond, WA?
It depends on the length of drain, the depth and the outlet. Describe the problem: contractors who serve Black Diamond reply with a quote.
How long does it take?
Most residential drains take one to three days.
Will a drain fix a wet basement?
It can help when water comes from the yard; inside problems may need waterproofing too.
Which drainage contractors will contact me?
Up to five independent drainage contractors who serve Black Diamond 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.