Chapter 20.520 NOISE IMPACT OVERLAY DISTRICT This chapter is included in your selections. Sections: 20.520.010 Purpose. 20.520.020 Establishment of Boundaries. 20.520.030 Applicability. 20.520.040 Approval Process. 20.520.050 Performance Standards. 20.520.060 Disclosure Statement Required. 20.520.070 Review and Modification.