A county required or choosing to plan under RCW 36.70A.040 may establish a process as part of its urban growth areas, that are designated under RCW 36.70A.110, for reviewing proposals to authorize new fully contained communities located outside of the initially designated urban growth areas.

(1) A new fully contained community may be approved in a county planning under this chapter if criteria including but not limited to the following are met:

(a) New infrastructure is provided for and impact fees are established consistent with the requirements of RCW 82.02.050;

(b) Transit-oriented site planning and traffic demand management programs are implemented;

(c) Buffers are provided between the new fully contained communities and adjacent urban development;

(d) A mix of uses is provided to offer jobs, housing, and services to the residents of the new community;

(e) Affordable housing is provided within the new community for a broad range of income levels;

(f) Environmental protection has been addressed and provided for;

(g) Development regulations are established to ensure urban growth will not occur in adjacent nonurban areas;

(h) Provision is made to mitigate impacts on designated agricultural lands, forestlands, and mineral resource lands;

(i) The plan for the new fully contained community is consistent with the development regulations established for the protection of critical areas by the county pursuant to RCW 36.70A.170.

(2) New fully contained communities may be approved outside established urban growth areas only if a county reserves a portion of the twenty-year population projection and offsets the urban growth area accordingly for allocation to new fully contained communities that meet the requirements of this chapter. Any county electing to establish a new community reserve shall do so no more often than once every five years as a part of the designation or review of urban growth areas required by this chapter. The new community reserve shall be allocated on a project-by-project basis, only after specific project approval procedures have been adopted pursuant to this chapter as a development regulation. When a new community reserve is established, urban growth areas designated pursuant to this chapter shall accommodate the unreserved portion of the twenty-year population projection.

Final approval of an application for a new fully contained community shall be considered an adopted amendment to the comprehensive plan prepared pursuant to RCW 36.70A.070 designating the new fully contained community as an urban growth area.