Chapter 20.420 HIGHER DENSITY RESIDENTIAL DISTRICTS Amended This chapter is included in your selections. Sections: 20.420.010 Purpose. 20.420.020 Zoning Districts. 20.420.025 Higher-Density Residential Zone Function and Location Criteria. 20.420.030 Uses. Amended 20.420.040 Minimum and Maximum Densities. 20.420.050 Development Standards. 20.420.060 Commercial Development Restrictions.