Low Impact Development, or "LID," is a stormwater and land use management strategy that strives to mimic
pre-disturbance hydrological processes of infiltration, filtrations, storage, evaporation and transpiration
by emphasizing conservation and use of on-site natural features, site planning, and distributed stormwater
management practices that are integrated into a project design. LID strategies can be applied to new development,
urban retrofits, infrastructure improvements and revitalization projects to protect aquatic resources.
The new municipal National Pollutant Discharge Elimination System (NPDES) permits in Western Washington require
use of Low Impact Development, where feasible. The Phase II Western Washington permit also requires the elimination of the 1-acre exemption, and for
jurisdictions covered under this permit to remove impediments and to implement Low Impact Development in their land use and development codes,
regulations and ordinances. Permits for Eastern Washington require allowing the use of Low Impact Development.
Western Washington Phase II and Phase I jurisdictions include 83 cities and 9 counties. Eastern Washington Phase II
jurisdictions include 18 cities and 6 counties.
The deadline for Western Washington Phase II jurisdictions to implement the new LID requirements is based their Growth Management
Act Comprehensive Plan Update timelines or December 31, 2016, whichever is later. Phase I jurisdictions are required
to implement the new LID requirements by June 30, 2015.
Industry Fact Sheets
Low Impact Development Series Articles, Building Insight
Low Impact Development Resources
BIAW has assembled a variety of resources-articles, reports, links and references-to LID material available
from other resources, as well as information and tools specifically developed by the Department of Ecology and partner
Top LID Websites
This site will continue to add links to a variety of resources regarding Low Impact Development, including manuals,
guidance documents, articles regarding LID techniques, and Educational and Technical Training opportunities.