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Thurston County, Washington

Community Planning and Economic Development

Low Impact Development (LID) Code Amendment

The Low Impact Development (LID) Code Amendment or Development Code Docket Item A-7 is a proposal that would amend development regulations related to land use and stormwater strategies within Title 20 - Zoning, Thurston County Code. This is a limited-focus review of some portions of the LID codes adopted in 2016. The proposal will correct inconsistencies and existing regulations that are not practical to meet or implement. 


Scope of the Project

The Board of County Commissioners affirmed that the purpose of the LID update is to address existing implementation challenges in the LID regulations that relate to:

  • Small lots under 2.5 acres;
  • Lots needing long access driveways; and
  • Internal code inconsistency with the Ken Lake Special Overlay District.
Staff proposes the following amendment to address the Board identified challenges:
  • Include terminology in the Zoning code from Thurston County’s Drainage Design and Erosion Control Manual that provides flexibility to property owners with irregularly shaped lots, flag lots, or lots needing long access driveways within current stormwater guidelines.
  • Clarify “ineffective impervious surfaces” as an area not counted towards the total for hard surface calculations. The amendment provides additional flexibility for landowners of large rural lots to meet hard surface requirements when they need a long access driveway.
  • Allows hard surface credits to apply to lots 2.5 acres or smaller. This amendment provides additional flexibility for landowners of small lots to meet hard surface requirements.
  • Adds an omitted reference to hard surface coverage for the Ken Lake Special Overlay District. The proposed staff-initiated change will address internal code inconsistency and ensure consistent LID regulations.


Notice of Adoption:

  • April 20, 2022 -  The Board of County Commissioners adopted the Low Impact Development (LID) ordinance at their regularly scheduled meeting on April 19, 2022 at 3pm. Select the "Adopted Ordinance No. 16151" below to view the adopted ordinance. If you have questions, contact


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Adopted Ordinance: 

A-7 - Adopted Ordinance No. 16151 - LID