Civil-Environmental Engineering
Shasta County

Cities and towns (requirements may differ)​

Unincorporated Communities

Summary of Specific Requirements For Gravity Systems

for Single Family Dwellings*

The following is in addition to the items listed on the FAQ page for Gravity System Requirements.


  • Vertical Separation to Water Table: 8', or 4' if parcel over 1 ac.

  • Trench Sidewall-to-Sidewall Separation: 8'

  • Trench Length:  10' to 125'

  • Bottom Width: 18" to 36"

  • Depth of Earth Coverage Over Lines: 36" max.

  • ​​​​Usable Material Below Trench Bottom: 12" min.

  • ​Minimum of 2" of gravel over drain lateral, and 12" under.

  • Maximum drop of 4" in 100' for drain lateral.

  • Trench Bottom: 150 sf min.​​


*The information on this page is a summary for quick reference only and may not represent the latest standards.  For complete and up-to-date information, see each counties official website.

Shasta County Setback Requirements

For a graphical representation of Shasta County setback requirements:


Links to Shasta County Website

For County home page:

For County's rules for

on-site sewage disposal:

(Development Standards

Manual, Chapter 5)