Wastewater Facilities

The Sanitation Districts operate 11 water reclamation plants (WRPs) and one ocean discharge facility (Joint Water Pollution Control Plant), which treat approximately 510 million gallons per day (mgd), 165 mgd of which are available for reuse. The capacities at these facilities range from 0.2 mgd (La Cañada WRP) to 400 mgd (Joint Water Pollution Control Plant); the San Jose Creek WRP is the largest of the water reclamation plants with a capacity of 100 mgd. Click here to view a map of the Wastewater Treatment Facilities.


Seventeen of the Sanitation Districts that provide sewerage services in the metropolitan Los Angeles area are also signatory to a Joint Outfall Agreement that provides a regional, interconnected system of facilities known as the Joint Outfall System (JOS). The service area of the JOS encompasses 73 cities and unincorporated territory, and includes some areas within the city of Los Angeles.

This system provides sewage treatment, reuse, and disposal for residential, commercial, and industrial users and includes the following treatment plants:

In addition, the system includes trunk sewers and pumping plants that convey sewage from member cities' local sewers to the Sanitation Districts' treatment plants. Sanitation District No. 2 acts as the agent for the other signatory Sanitation Districts in administering the Joint Outfall Agreement.


The Santa Clarita Valley Sanitation District operates the Saugus and Valencia WRPs.

Sanitation Districts Nos. 14 and 20 serve the Antelope Valley and operate the Lancaster and Palmdale WRPs, respectively.


  • Sanitation Districts Nos. 4, 9, and 27 are served by contracts with the city of Los Angeles.
  • Sanitation District No. 34, located in La Cresenta, has not yet constructed sewerage systems. This Sanitation District is currently inactive and sewerage service in this area is provided by individual private disposal systems.

Click here to view the treatment process at the WRPs.


The Sanitation Districts have received numerous wastewater awards.  Click here to read more.