The Onsite Wastewater Treatment Program of the Environmental Health Division reviews proposed Onsite Wastewater Treatment Systems designs, work plans, required covenants, historical records, and performs site and installation inspections prior to issuing final system design approvals. System design approvals may be submitted to your local Building and Safety Department to obtain building permits for proposed projects.

Property owners must submit Conventional or Non-Conventional Onsite Wastewater Treatment System plans to any Onsite Wastewater Treatment Program field office or to the Environmental Health Division Headquarters for review. Once approved, stamped and approved plans are then provided to the applicant.

Responsibilities of the Onsite Wastewater Treatment Program include reviewing and approving plans for Conventional and Non-Conventional Onsite Wastewater Treatment Systems within unincorporated areas of Los Angeles County and designated cities that have signed the County’s LAMP MOU.

Conventional Onsite Wastewater Treatment Systems (OWTS)

Home and business property owners that want to install or replace an onsite wastewater treatment system must submit an application and the required documents listed on the application in order to go through the OWTS review process.

For more information on requirements and procedures for Conventional and Non-conventional Onsite Wastewater Treatment Systems.

A listing and delisting 303(d) of new impaired water body can be reviewed at: 2024 California Integrated Report, Appendix J

Property owners with existing Onsite Wastewater Treatment Systems must have a system evaluation completed by a qualified professional when proposing property improvements.

Non-Conventional Onsite Wastewater Treatment Systems (NOWTS)

Home and business property owners that want to install a NOWTS must submit a covenant and agreement form.

Additional Documents

Los Angeles County Department of Public Health (LACDPH) reviews and approves OWTS under the provisions of the LAMP to residents of unincorporated county areas and contracted cities. Cities must adopt the appropriate sections of the Los Angeles County Health and Safety Code (Title 11) and the Los Angeles County Plumbing Code (Title 28) before entering a Memorandum of Understanding (MOU) with the County to be covered under the LAMP’s provisions and restrictions. For more information regarding the LAMP, please visit our LAMP page. LAMP cities that have an MOU with the County include:

  • Agoura Hills
  • Bradbury
  • Duarte
  • Glendora
  • Hidden Hills
  • La Canada Flintridge
  • La Habra Heights
  • La Verne
  • Lomita
  • Lancaster
  • Palmdale
  • Palos Verdes Estates
  • Rancho Palos Verdes
  • Rolling Hills
  • Rolling Hills Estates
  • Santa Clarita

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Report a Problem

If you have questions or concerns about conventional or non-conventional onsite wastewater treatment systems, contact the Onsite Wastewater Treatment Program at (626) 430-5380. For complaints, contact the Environmental Health Call Center at (888) 700-9995 or File a Complaint Online.

Contact Us

Monday - Friday
8:00am - 5:00pm

Tel: (626) 430-5380
Fax: (626) 813-3016

County of Los Angeles Public Health
Environmental Health
Onsite Wastewater Treatment Program
5050 Commerce Drive
Baldwin Park, CA 91706