Project Background

LADWP is in the process of converting the city’s drinking water supply to chloramine as the secondary treatment, replacing chlorine, to comply with Federal water quality regulations. As part of this effort, the LADWP will construct the 99th Street Water Treatment Plant in South Los Angeles to provide chloramine treatment to the groundwater supply distributed by the 99th Street Wells Pumping Station Complex. The new station will replace the existing chlorine system with a safer on-site treatment system. The 99th Street Water Treatment Plant will be a single-story, 2,300-square-foot building, constructed within the existing 99th Street Wells Pumping Station Complex property, located at 9880 Wadsworth Avenue in the Watts community.

Purpose and Benefits

Conversion to chloramine treatment is being achieved by adding ammonia to chlorine, and is the LADWP’s strategy to comply with the drinking water regulation, Stage 2 Disinfectants and Disinfection Byproduct (D/DBP) Rule. Although both chlorine and chloramine effectively kill bacteria and other microorganisms, chloramine forms less DBPs, and produces less chlorine odor. To learn more about the LADWP’s system-wide conversion to chloramines, please go to Fact Sheets & Brochures – System-wide Chloramine Expansion.

In addition, water treated with chloramine also increases the flexibility of the LADWP water operations, since water imported from the Metropolitan Water District of Southern California (MWD) is also treated with chloramine and enters the city at many locations. MWD is a regional wholesaler that delivers water to numerous public agencies throughout Southern California, including the City of Los Angeles.

Construction Schedule

Groundbreaking: Mid-September 2016
End of construction: November 2018

Environmental Documentation

California Environmental Quality Act Process:
The Mitigated Negative Declaration Report (MND) was released for public review on December 1, 2015. The document was approved and filed in May 2016.

Final MND Report

For additional information regarding the LADWP environmental reports, go to Archived Environmental Reports

Watts Area Water Quality

The 99th Street Water Treatment Plant Project, which has been in the planning stages for several years, is unrelated to the recent problem of cloudy and discolored water in Watts and Green Meadows communities. LADWP has addressed that issue by flushing all of the pipes in the area and cleaning the pump forebay. LADWP may implement additional Water Quality initiatives in the Watts and Green Meadows areas to address naturally occurring iron and manganese levels in the 99th Street groundwater. 

Water Quality

Learn more about LADWP Water Quality .

LADWP Contact Information

Brian Tan, Project Manager, (213) 367-3487 or [email protected]
Thayne Devorss, Construction Manager, (213) 367-4381 or [email protected]
Dawn Cotterell, Community Relations, (213) 367-4208 or [email protected]

Updated on August 24, 2016