King County Post-Construction Soil Standard

ByAdmin

If you’re working on a construction or landscaping project in King County, WA, you’re likely required to comply with the Post-Construction Soil Standard. This regulation helps prevent runoff, protect water quality, and restore the soil’s ability to absorb and filter rainwater.

But to comply, you need to know how much soil (and compost) to apply and that’s where our Topsoil Calculator becomes essential.

What Is the King County Post-Construction Soil Standard?

The King County Post-Construction Soil Standard is a local requirement that ensures disturbed soils are restored to a healthy condition after construction. The goal is to:

  • Improve soil structure
  • Increase organic matter
  • Boost water infiltration and retention
  • Reduce stormwater runoff and erosion

This standard applies to residential, commercial, and municipal projects involving land disturbance or development.

Why Soil Volume Matters for Compliance

To meet the standard, you must apply soil amendments like compost at a specific depth and rate usually to achieve a minimum of:

  • 8 inches of amended soil depth, or
  • Till-in 2 inches of compost into 6 inches of native soil

But how much soil and compost is that in cubic yards? Our tool gives you the answer.

Use the Topsoil Calculator for Fast, Compliant Estimates

The Topsoil Calculator allows you to:

  • Enter the area size in feet (length × width)
  • Set the required soil depth in inches or feet
  • Get instant soil volume in cubic yards

This is especially useful when planning for:

  • Compost amendment application
  • Soil restoration in planting beds or turf areas
  • Estimating bulk bags or truckloads for delivery
  • Budgeting for materials in permitting applications

Who Needs This?

This applies to:

  • Builders & general contractors
  • Landscape architects & designers
  • Municipal projects and green infrastructure work
  • Anyone needing to meet stormwater permit conditions in King County

Pro Tip: Use with Compost Soil Improver

Once you calculate how much soil is needed, you can also determine how much compost soil improver to apply at a rate of 2–3 inches. Just set the depth accordingly in the calculator.

Final Thought

Whether you’re building a backyard patio or managing a commercial landscape, meeting the King County Post-Construction Soil Standard starts with accurate soil planning.

Use our Topsoil Calculator to instantly estimate how much soil and compost you need and stay compliant, sustainable, and efficient.

Frequently Asked Questions (FAQs)

1. What is the King County Post-Construction Soil Standard?
It’s a regulation requiring disturbed soils to be restored with compost-amended soil to improve drainage and reduce runoff.

2. How much amended soil is required for compliance?
Typically, 8 inches of amended soil or 2 inches of compost tilled into 6 inches of native soil is required.

3. How can I calculate how much soil or compost I need?
Use our Topsoil Calculator to estimate cubic yards based on area size and target depth.

4. Who needs to follow this standard?
Builders, landscapers, and homeowners in King County involved in site development or post-construction soil restoration.

5. Does the calculator work for compost coverage too?
Yes, just set your depth for compost (e.g. 2 inches), and the calculator will give you the volume in cubic yards for ordering.

Similar Posts