(1) Comprehensive plans must be internally consistent. This requirement means that differing parts of the comprehensive plan must fit together so that no one feature precludes the achievement of any other.

(2) Use of compatible assumptions. A county or city must use compatible assumptions in different aspects of the plan.

(a) A county or city should use common numeric assumptions to the fullest extent possible, particularly in the long-term growth assumptions used in developing the land use, capital facilities and other elements of the comprehensive plan.

(b) If a county or city relies on forecasts, inventories, or functional plans developed by other entities, these plans might have been developed using different time horizons or different boundaries. If these differences create inconsistent assumptions, a county or city should include an analysis in its comprehensive plan of the differences and reconcile them to create a plan that uses compatible assumptions.

(3) The development regulations must be internally consistent and be consistent with and implement the comprehensive plan.

(4) Consistency review. Each comprehensive plan should provide mechanisms for ongoing review of its implementation and adjustment of its terms whenever internal conflicts become apparent. At a minimum, any amendment to the comprehensive plan or development regulations must be reviewed for consistency. The review and update processes required in RCW 36.70A.130 (1) and (3) should include a review of the comprehensive plan and development regulations for consistency.

(5) See WAC 365-196-800 for more information on the relationship between development regulations and the comprehensive plan. See WAC 356-196-305 for more information on the relationship between countywide planning policies and the comprehensive plan. See WAC 365-196-315 (5)(a) for information on consistencies between assumptions and observed development for cities or counties subject to monitoring requirements in RCW 36.70A.215.