Image of reservoir

Investments to improve drinking water quality are the largest component of the LADWP’s Water System Capital Improvement Program. From fiscal years 2011/12 through 2015/16, planned water quality capital expenditures are approximately $1.4 billion, which is 40% of the total capital budget. These efforts are primarily driven by projects to safeguard the City’s surface water supplies, and a citywide conversion to chloramines to disinfect our drinking water supply.

    Aerial image of a UV disinfection facility

    The Los Angeles Department of Water and Power is currently completing the construction of a new Ultraviolet (UV) Disinfection Facility at the Los Angeles Reservoir. This second UV plant will supplement the existing Dr. Pankaj Parekh Ultraviolet Disinfection Facility currently treating water coming into the reservoir from the Eastern Sierra and the Bay Delta. The second plant will treat water leaving the reservoir and entering LA’s water distribution system. The new state-of-the-art LA Reservoir UV Disinfection Plant is an important investment in the reliability and safety of LA’s drinking water infrastructure, greatly enhancing LADWP’s mission to deliver pure, clean refreshing tap water to our customers in an efficient and publicly responsible manner.

    UV Disinfection

    The use of UV to disinfect drinking water safely and rapidly is a relatively new, but effective technology. UV light is not visible to the naked eye but it is very effective in attacking harmful organisms and disrupting the DNA in viruses, bacteria and protozoa. The technology is ideal for treating chlorine-resistant micro-organisms like Cryptosporidium and Giardia. UV treatment will provide essential disinfection while minimizing disinfection by-products, reducing the need for the required chlorine doses. It will further assist LADWP in complying with the Long Term 2 Enhanced Surface Water Treatment Rule (LT2) and is an important element in achieving system-wide regulatory compliance.

    UV Plant Specifics

    Building Space: The main UV building will be approximately 319 feet long by 95 feet wide, with a ceiling height of approximately 28 feet to 38 feet.

    Maximum Flow Rate: 650 million gallons a day (MGD)

    Inlet Configuration: The 144-inch inlet pipe will be split into two 108-inch headers to allow for simplified flow-splitting within the facility and for finer adjustment of the flow rate.

    Outlet Configuration: Outflow from the plant will exit through the two 108-inch outlet headers and enter a 144-inch trunk line. The flow will then pass through a flow control station to allow operators to tailor the flow rate to specific customer needs.

    Number of Reactors: 13 available for maximum flow with 2 backup reactors

    Number of UV Lamps per reactor: 5 UV lamps at 20kW per lamp

    Back-up Power: A combination of two 1,100 kVA uninterruptible power supplies and a 2,500kW backup diesel generator.

    Start of Construction: Late 2016

    In Service Date: January 31, 2022

    Project Cost: $123.8 Million

    Funding Source: Pass-Thru funded through water rates

    For Information and updates, go to 99th Street Wells Chloramination Station Project.


    For information and updates, go to Charing Cross and Hilgard Bypass Line.


    For information and updates, go to Elysian Reservoir Water Quality Improvement Project.


    For information and updates, go to Fairmont Sedimentation Project.


    For information and updates, go to Green Verdugo Reservoir Floating Cover Replacement Project.


    Construction Photos

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    In response to the Stage 2 Disinfectant/Disinfection Byproducts Rule, the Water System is undertaking a number of capital improvement projects to reduce the formation of disinfection byproducts. Currently at the Los Angeles Aqueduct Filtration Plant (LAAFP), the disinfection requirements are met through a combination of ozone, filtration, and chlorine treatments. The addition of an ultra violet (UV) light treatment facility at the LAAFP will help to reduce the formation of byproducts by providing pathogen disinfection while allowing for reduced use of ozone and chlorine. Low doses of UV are required to disinfect the water of Giardia lambia and cryptosporidium while not producing any known byproducts.

    The UV facility will be constructed to treat the water following the filtration process. Chlorine will continue to be used to achieve virus disinfection. The final treatment step will then be the injection of ammonia into the water to combine with the chlorine and form the chloramine residual.


    The UV facility will be housed in an approximately 13,000 square foot main building on the Van Norman Reservoir Complex at the south end of the LAAFP. Immediately adjacent to the main building’s east side will be a covered inlet channel and on the west side a similar covered outlet channel. A 144-inch diameter pipeline approximately 125 feet long will bring the water into the inlet channel of the UV building with a second similarly sized pipeline delivering the treated water back from the outlet channel into the water distribution network. In addition, pipeline will be installed to transfer treated water from the UV facility’s outlet channel to the Los Angeles Reservoir. Ancillary facilities to house the electrical transformers, etc. will be constructed in close proximity to the UV building.


    Construction is continuing on schedule to meet the March 2014 operational date. The electrical building construction is 90% complete and the electrical equipment is beginning to be installed. The metal building over the UV reactors is being erected. The first UV reactor was set into position during the last week of June. The remaining reactors will be delivered to the site during July and August. Testing of the reactors is scheduled to begin in late August as well. During the testing period, the water will continue to be disinfected using ozone and chlorine as it has been for the last 25+ years at LAAFP. During this period, the UV will be providing an additional safety factor, above and beyond what is required by the California Department of Public Health for disinfection. Only after the UV has been permitted for full-time operation, then the use of ozone and chlorine will be significantly reduced.

    LADWP Contact Information

    For additional information regarding this project, contact Mr. Stephen Ott, Planning Manager, at (213) 367-4187.

    Updated July 15, 2013

    For information and updates, go to Lower Franklin Reservoir No. 2 Floating Cover Replacement.


    Aerial image of Mission Wells facility displaying the existing pump station, the existing water tank, and the location of the new chloramination station.

    The Mission Wells Facility is located in the northeast San Fernando Valley community of Sylmar at 12331 Havana Avenue, Los Angeles, California.

    The new facility will replace the current chlorine system and will provide chloramine disinfection to the groundwater supply distributed by the Mission Wells Facility.

    The project scope includes the installation of a new chloramination station that will house an ammoniation station and on-site hypochlorite generating station, improvements to an existing drainage channel, and construction of a new access road within the Mission Wells Facility.


    The project is currently in the final design phase.

    Construction Schedule
    Spring of 2022 - Summer of 2024

    Fact Sheet

    Contact Information

    Priscilla Gonzalez, Project Manager
    (213) 367-4738 | [email protected]

    Christina Holland, Community Liaison
    (213) 367-1076 | [email protected]

    Project Background

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    LADWP is in the process of converting its water disinfection process from chlorine to chloramines. Construction of the North Hollywood Ammoniation Station (NHAS) is another step in LADWP’s effort to convert its water supply to chloramine disinfection.

    While the LADWP is in compliance with existing water quality regulations, it is necessary to comply with the more stringent regulations that will be in place in the next few years and to improve the water supply reliability by augmenting the City of Los Angeles’ water supply with chloraminated water purchased from the Metropolitan Water District (MWD). To this end, the LADWP is designing and constructing chloramination and ammoniation facilities to convert the entire water distribution system to chloramine disinfection.

    Scope of Project

    The NHAS construction project is located at the LADWP’s North Hollywood Pump Station Complex (located near Vanowen Street at Hinds Street) and two other LADWP properties. Work will be performed within LADWP’s property limits with minimal impact on the community. The project is divided as follows:

    Phase 1 – Construction of the 2,800 square-foot NHAS, appropriate controls, and equipment. Construction was completed in September 2010. The commissioning of the NHAS commenced in November 2013 and can be completed in February 2014.

    Phase 2 – Two onsite hypochlorite generation stations (OSHG) to treat water from the North Hollywood - West Branch Well Collector Line (located near Vanowen Street at Whitsett Avenue) and the Rinaldi Toluca Well Collector Line (located near Vose Street at Radford Street) are being constructed and will be in service in February 2014. These stations will generate low-concentration chlorine to provide disinfection for groundwater. Please see the fact sheet for more information on the OSHG stations which can be accessed throught the link below.

    North Hollywood Ammoniation Station Project Fact Sheet

    Current Status

    Phase 1 – Construction of the ammoniation building was completed in September 2010.

    Phase 2 – Construction of both OSHGs has commenced. Both structures are being constructed on LADWP property located in the area of North Hollywood. The completion date of both buildings was December 2013.

    LADWP Contact Information

    For additional information regarding this project, contact Mrs. Heidi Hiraoka, Project Manager, at (213) 367-5263 or by e-mail at [email protected].

    Updated February 3, 2014

    For information and updates, go to the Silver Lake Reservoir Complex Bypass Project.


    For information and updates, go to the Upper Stone Canyon Reservoir Water Quality Improvement Project.