(1) The role of urban areas in the act. The act requires counties and cities to direct new growth to urban areas to allow for more efficient and predictable provision of adequate public facilities, to promote an orderly transition of governance for urban areas, to reduce development pressure on rural and resource lands, and to encourage redevelopment of existing urban areas.

(2) How the urban density requirements in the act are interrelated. The act involves a consideration of density in three contexts:

(a) Allowed densities: The density, expressed in dwelling units per acre, allowed under a county's or city's development regulations when considering the combined effects of all applicable development regulations.

(b) Assumed densities: The density at which future development is expected to occur as specified in the land capacity analysis or the future land use element. Assumed densities are also referred to in RCW 36.70A.110 as densities sufficient to permit the urban growth that is projected to occur.

(c) Achieved density: The density at which new development occurred in the period preceding the analysis required in either RCW 36.70A.130(3) or 36.70A.215.

(3) Determining the appropriate range of urban densities. Within urban growth areas, counties and cities must permit urban densities and provide sufficient land capacity suitable for development. The requirements of RCW 36.70A.110 and 36.70A.115 apply to the densities assumed in the comprehensive plan and the densities allowed in the implementing development regulations.

(a) Comprehensive plans. Under RCW 36.70A.070(1) and in RCW 36.70A.110(2), the act requires that the land use element identify areas and assumed densities sufficient to accommodate the 20-year population allocation. The land use element should clearly identify the densities, or range of densities, assumed for each land use designation as shown on the future land use map. When reviewing the urban growth area, the assumed densities in the land capacity analysis must be urban densities.

(b) Development regulations. Counties and cities must provide sufficient capacity of land suitable for development.

(i) Development regulations must allow development at the densities assumed in the comprehensive plan.

(ii) Counties and cities need not force redevelopment in urban areas not currently developed at urban densities, but the development regulations must allow, and should not discourage redevelopment at urban densities. If development patterns are not occurring at urban densities, counties and cities should review development regulations for potential barriers or disincentives to development at urban densities. Counties and cities should revise regulations to remove any identified barriers and disincentives to urban densities, and may include incentives.

(4) Factors to consider for establishing urban densities. The act does not establish a uniform standard for minimum urban density. Counties and cities may establish a specified minimum density in countywide or multicounty planning policies. Counties and cities should consider the following factors when determining an appropriate range of urban densities:

(a) An urban density is a density for which cost-effective urban services can be provided. Higher densities generally lower the per capita cost to provide urban governmental services.

(b) Densities should be higher in areas with a high local transit level of service. Generally, a minimum of seven to eight dwelling units per acre is necessary to support local urban transit service. Higher densities are preferred around high capacity transit stations.

(c) The areas and densities within an urban growth area must be sufficient to accommodate the portion of the 20-year population that is allocated to the urban area. Urban densities should allow accommodation of the population allocated within the area that can be provided with adequate public facilities during the planning period.

(d) Counties and cities should establish significantly higher densities within regional growth centers designated in RCW 47.80.030; in growth and transportation efficiency centers designated under RCW 70.94.528; and around high capacity transit stations in accordance with RCW 47.80.026. Cities may also designate new or existing downtown centers, neighborhood centers, or identified transit corridors as focus areas for infill and redevelopment at higher densities.

(e) Densities should allow counties and cities to accommodate new growth predominantly in existing urban areas and reduce reliance on either continued expansion of the urban growth area, or directing significant amounts of new growth to rural areas.

(f) The densities chosen should accommodate a variety of housing types and sizes to meet the needs of all economic segments of the community. The amount and type of housing accommodated at each density and in each land use designation should be consistent with the need for various housing types identified in the housing element of the comprehensive plan.

(g) Counties and cities may designate some urban areas at less than urban densities to protect a network of critical areas, to avoid further development in frequently flooded areas, or to prevent further development in geologically hazardous areas. Counties or cities should show that the critical areas are present in the area so designated and that area designated is limited to the area necessary to achieve these purposes.

(5) Addressing development patterns that occurred prior to the act.

(a) Prior to the passage of the act, many areas within the state developed at densities that are neither urban nor rural. Inside the urban growth area, local comprehensive plans should allow appropriate redevelopment of these areas. Newly developed areas inside the urban growth area should be developed at urban densities.

(b) Local capital facilities plans should include plans to provide existing urban areas with adequate public facilities during the planning period so that available infrastructure does not serve as a limiting factor to redevelopment at urban densities.