Wastewater Collection Systems

The Sanitation Districts are a partnership of 24 independent special districts that serve the wastewater and solid waste management needs of approximately 5.5 million people in Los Angeles County (County). The Sanitation Districts' service area covers approximately 824 square miles and encompasses 78 cities and unincorporated territory within the County. Within the Sanitation Districts' service area, there are approximately 9,500 miles of sewers that are owned and operated by the cities and County that are tributary to the Sanitation Districts' wastewater collection system. The Sanitation Districts own, operate, and maintain approximately 1,400 miles of sewers, ranging from 8 to 144 inches in diameter, that convey approximately 500 million gallons per day of wastewater to 11 wastewater treatment plants. Included in the Sanitation Districts' wastewater collection system are 48 active pumping plants located throughout the County. The Sanitation Districts' service area includes wastewater collection systems located within the Joint Outfall System, the Santa Clarita Valley, and the Antelope Valley.


In Los Angeles County, the sewer system consists of 17,000 miles of underground pipes that include the publicly-owned pipes noted above as well as the private pipes that connect homes and businesses to the system.  Sewer systems have been around for thousands of years and are essential in protecting public health and the environment, and maintaining clean and safe communities.  The modern development of sewer systems and treatment plants is considered one of the most effective public health improvements in history.  Click here to learn more.


The Sanitation Districts maintain a Wastewater Collection System Operation and Maintenance Program consisting of the following elements:

  • Computerized Work and Asset Management (WAM) System
    • Preventive Maintenance (PM) Schedule
    • Work Order System
    • Purchasing
    • Cost Tracking

  • Geographical Information System 

  • Sewer System Management Plan, updated February 2019 (SSMP, file size 3.31 MB)
    • The 2019 SSMP was approved on the dates listed below.  Click here to access the meeting minutes.
      • February 13, 2019 – Sanitation Districts Nos. 1, 2, 3, 4, 8, 19, and Santa Clarita Valley
      • February 20, 2019 – Sanitation District No. 29
      • February 25, 2019 – Sanitation Districts Nos. 5 and South Bay Cities
      • February 27, 2019 – Sanitation Districts Nos. 14 and 20
      • February 28, 2019 – Sanitation Districts Nos. 15, 16, 17, 18, 21, 22, and 28 
    • The SSMP includes a Sanitary Sewer Overflow Response Plan.  If you have questions, please contact Darrell Hatch via the email link or at (310) 638-1161, extension 6808.

  • Operation and Maintenance Programs
    • Line Cleaning/Checking
    • Manhole Cover Adjustments
    • Pumping Plants
    • Root Control
    • Siphon Cleaning

  • Odor and Corrosion Control Programs
    • Carbon Canisters
    • Caustic Treatment
    • Crown Spray Program
    • Ferrous Chloride Treatment
    • Mobile Odor Scrubbers
    • Odor Control Stations
    • Sulfide Circuits

  • Condition and Capacity Assessment Programs
    • Closed-Circuit Television (CCTV) Inspection
    • Flow Monitoring
    • Flow Modeling
    • Physical Inspection


The Santa Clarita Valley Sanitation District owns, operates, and maintains the wastewater conveyance system for the Santa Clarita Valley which consists of a 34-mile long, interconnected network of trunk sewers and two pumping plants. The system conveys wastewater and wastewater solids from the local sewer lines to the Saugus and Valencia Water Reclamation Plants. Local lines are sewers that, typically, convey wastewater from a user's property line to the trunk sewers.

The City of Santa Clarita owns the local sewers within its borders, and Los Angeles County owns the majority of the local sewers located in unincorporated areas. The Los Angeles County Consolidated Sewer Maintenance District operates and maintains these local sewers.


The wastewater conveyance system for the Antelope Valley consists of a network of trunk sewers and local sewers serving the Palmdale and Lancaster service area. Approximately 40 miles of interconnected trunk sewers convey wastewater generated within Palmdale to the Palmdale Water Reclamation Plant and approximately 64 miles of trunk sewers convey wastewater generated within Lancaster to the Lancaster Water Reclamation Plant. All trunk sewers convey wastewater by gravity flow and, therefore, no pumping plants are necessary.

The cities of Palmdale and Lancaster own and maintain the local sewers within their respective city limits and Los Angeles County owns the majority of the local sewers in unincorporated areas. The Los Angeles County Consolidated Sewer Maintenance District operates and maintains the local sewers within the unincorporated service areas.  

Contacts in the event of a sewage related overflow, emergency, or odor problem:

Local City & County Contacts

Sanitation Districts of Los Angeles County
24-Hour Emergency Hotline (562) 437-6520