State law defines critical areas as wetlands, frequently flooded areas, fish and wildlife habitat, geologically hazardous areas (steep slopes, erosion and landslide hazards) and critical aquifer recharge areas (RCW 36.70A). The regulations seek to protect the functions and values of these environmentally and geological features to provide for a healthy environment, public benefit, public safety and provide for reasonable use of these areas to property owners.
The City adopted a Critical Areas Ordinance in 2004, codified as Chapter 16.15 of the Mountlake Terrace Municipal Code (MTMC). The purpose of the critical areas regulations is to protect the functions and values of those areas at the local level. The City updated its Critical Areas regulation in 2018.