Click here to download Rebuilding a Home with an Existing Septic System document

Properties with an existing septic system, verified by a qualified licensed contractor* and determined to be in good working condition may use the existing septic system if the property is:

Rebuilding Like-For-Like:

• Same number of bedrooms or bedroom equivalents (same location with a possibility of floor plan modification of up to 10%)
• Fully accommodated by the existing septic system
• All setback requirements are met

Rebuilding as a New construction:

• Equivalent structure with original floor plan, using existing septic system, sized correctly for the number of bedrooms or bedroom equivalents
• Proper distance between the septic system and structures (house, retaining walls, pools, decks, and other features) must meet system components standards

Rebuilding with New/Modified floor plan:

• Proposing additional bedrooms or bedroom equivalents will require Public Health permits for a compatible septic system

* A qualified licensed contractor holds a valid California Contractors License as Class A, C 42, or C 36.

Properties with an existing septic system, verified by a qualified licensed contractor* and determined NOT to be in good working condition should contact Public Health for guidance on how to bring the septic system back into compliance.

A septic system that is NOT in good working order is considered failing. A failing septic system is one that can no longer safely treat or discharge wastewater.

Properties with an existing septic system, verified by a qualified licensed contractor* and determined to be in good working condition:

• May rebuild using the existing septic system if rebuilding with the same number of bedrooms and bedroom equivalents.
• May NOT rebuild using the existing septic system and must connect to the public sewer system if:
  • There is an expansion or modifications to the property
  • There is a subsequent failure of the septic system
  • The existing system is NOT in good working condition

If the Department of Public Works (DPW) determines the property is not capable of receiving a connection to the public sewer, the property owner may obtain a waiver from DPW to use the existing septic system. Contact DPW at AltadenaSewer@pw.lacounty.gov

A cesspool is a lined pit that receives and stores sewage directly from the house, without the use of a septic tank. If a property owner wishes to rebuild with additional bedrooms or bedroom equivalents, the cesspool must be upgraded to a septic system or connected to the public sewer if located within 200 linear ft. Approval must be obtained from Public Health if converting to a septic system.

Guidance for Properties with existing cesspools in the Eaton Fire Burn Area

Use of existing cesspools will be permitted during reconstruction if the following applies:

Functionality Verification:

• Each cesspool must show it works by obtaining a percolation test conducted by a Qualified
  Professional (QP).
• Testing must follow the procedures outlined in the County of Los Angeles Local Agency
  Management Program (LAMP) and meet the minimum percolation rate criteria specified
  in Table 3-2 of the LAMP.
• The County Department of Public Health will review and approve all test results.

No Increase in Wastewater Flow:

• Property owners may not increase wastewater flow to an existing cesspool.
• There can be no reconstruction that adds bedrooms, bathrooms, or bedroom equivalents,
  such as Accessory Dwelling Units (ADUs).
• Reconstruction plans must show the number of previously permitted bedrooms and
  bathrooms; any changes require prior approval from the Department of Public Health.

For more information, please contact:
Environmental Health, Onsite Wastewater Treatment Program
(626) 430-5380 or dlanduse@ph.lacounty.gov