PUD concept plan review. During PUD Concept Plan review, the PUD Concept Plan application is reviewed with respect to such issues as density, including the number, type, and location of dwelling units and other uses; impacts on surrounding areas; and the adequacy of facilities and services. The result of this review is the establishment of the basic parameters for development of the PUD project. PUD Concept Plan approval establishes the maximum development "envelope" for the project, with regard to density, lot sizes, overall scale, open space, environmental protection, and other land development and service provision issues.