San Francisco Administrative Code Chapter 21 Chapter 21 governs how City departments can purchase goods, general services and professional services. Resources San Francisco Administrative Code Chapter 21 Administrative Code Chapter 21 Read the full version of the law governing purchasing and contracting in San Francisco. Administrative Code Chapter 21 with Rules and Regulations Incorporated This document incorporates the Rules and Regulations accompanying Chapter 21 into a single document for easier reference. Departments Office of Contract Administration