Mainline Extensions


Mainline Extensions
Guidelines, Checklists, and Information

A property owner or developer seeking to install new public sewer facilities to serve their properties must fund, design, construct, and provide appropriate land-rights for the proposed public sewer facilities in compliance with District Code and Standard Specifications. 

Below are guidelines to assist the Applicant and Engineer in the mainline review process. For more details, please see Part III. Public Sewer Collection Systems of Central San’s Standard Specs.

Note: ​

  • Central San is prohibited from using existing ratepayer funds to install infrastructure to serve new customers (Reference: Health and Safety Code §5471 and §6520.5). 
  • Public and private sewers have the same design criteria. 


Applicant Guide to Sewer Main Extension

Compliance Checklists 

Design Concept
Plan Preparation
Permitting for Construction


Owner's Improvement Agreement
Project Security Bond Form
Variance Request Form


Plan Set Tables
Public Cost Estimate
Cut Sheet