Cities and towns (requirements may differ)
*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.
Summary of Requirements For Gravity Systems*
Lassen County uses the California Uniform Plumbing Code with the following modifications:
Trench Sidewall-to-Sidewall Separation: 4'
Minimum Spacing Between Lines: 6 ft
Minimum Total Trench Length: 100 ft
Maximum Trench Length each: 100 ft
Bottom Width: 18" to 36"
Trench Depth: 3 ft minimum
Minimum of 2" of gravel over drain lateral, and 12" under.
Drain Line and Trench Bottom must be level.
All Drain Lines should be of equal length.
Drain rock should be 1 1/2" to 3", covered with straw, untreated building paper or filter fabric.
For general requirements and good practices see the FAQ page for Gravity System Requirements:
For UPC specifics:
For Lassen County Individual Sewage Disposal System Handout 2005 version (copy obtained July 2013) - includes setback table and diagram:
For Lassen County Chapter 12 Septic Regulations (copy obtained July 2005):
Links to Lassen County Website
For County home page:
For County Building Code: