All cities and counties in Washington are required to adopt critical areas regulations by the Growth Management Act (GMA) (RCW 36.70A.060). As defined by the GMA,"Critical areas" include the following areas and ecosystems: (a) Wetlands; (b) areas with a critical recharging effect on aquifers used for potable water; (c) fish and wildlife habitat conservation areas; (d) frequently flooded areas; and (e) geologically hazardous areas. [RCW 36.70A.030(5)]
Counties and cities are required to include the best available science in developing policies and development regulations to protect the functions and values of critical areas (RCW 36.70A.172). All jurisdictions are required to review, evaluate, and, if necessary, revise their critical areas ordinances according to an update schedule.
Department of Commerce: Critical Areas - This state department compiled resources to assist with critical areas planning.
Department of Commerce: Critical Areas Handbook - A booklet which states critical area statutes and rules for State of Washington local governments.
MRSC: Critical Areas Planning - This local government technical assistance organization compiled resources for critical areas planning.