Low Impact Development

The County’s stormwater regulations are a key to promoting clean water entering our water bodies including Puget Sound. A primary component of the county’s stormwater regulations is the requirement for the use of low impact development best management practices (LID BMPs), where feasible.

LID BMPs are distributed stormwater management practices, integrated into a project design, that emphasize pre-disturbance hydrologic processes of filtration, storage, evaporation, infiltration and transpiration. LID BMPs include, but are not limited to, bioretention/rain gardens, permeable pavements, roof downspout controls, dispersion, soil quality and depth, minimal excavation foundations, vegetated roofs, and water re-use.

For more information on LID BMPs and feasibility see Assistance Bulletins #22 and #108

Rain Garden Illustration2

On September 27, 2018, Snohomish County Planning and Development Services (PDS) hosted a Low Impact Development (LID) workshop for builders and developers. The goal of the workshop was to improve the knowledge and capability of the development community in Snohomish County to effectively implement LID principles and best management practices (BMPs). The Training was also designed to help the development community understand PDS’s project review and electronic submittal process that went live September 1, 2018.


Nearly 60 members of the development community in Snohomish County came together for hands-on site assessment training from PDS, Herrera, and Associated Earth Sciences. A full list of participants is provided.


For more information about Low Impact Development, please see our Resources document.