Construction work has begun on a new water treatment plant in South Los Angeles that will use chloramine, instead of chlorine, to disinfect drinking water.

Councilman Marqueece Harris-Dawson (8th District) said the change to chloramine—which is being made to meet federal regulations—will “ensure that residents of Green Meadows and Watts have access to the highest quality water.”

Harris-Dawson recently took part in a groundbreaking ceremony for the $19.1 million chloramine facility—to be built at the 99th Street Water Treatment Plant in the 9800 block of Wadsworth Avenue—that will serve about 20,000 households, businesses and multi-family complexes.

The project is not expected to be completed until late 2018, but the area it serves was briefly switched to chloramine-treated water earlier this year after some residents and school officials reported discoloration in their water.

Los Angeles Department of Water and Power (DWP) officials shut down the 99th Street Plant at the time so that they could flush out sediment from the area’s water mains. During that time, chloramine-treated water had to be piped in from an adjacent area.

Utility officials have said that despite its unappetizing appearance, the discolored water ultimately was safe enough to drink and marred only by naturally occurring iron and manganese.

DWP officials said the discoloration issue was “resolved,” and is unrelated to the construction of the new chloramine treatment facility, which was long planned and part of a wider effort to meet U.S. Environmental Protection Agency requirements.

Most other areas of the city have switched to chloramine, including downtown Los Angeles, Hollywood and the San Fernando Valley. Treatment facilities serving the San Pedro and East Los Angeles areas have also been using chloramine for many years.

The 99th Street Water Treatment Plant in South Los Angeles will be the last local well to be converted to chloramine, according to DWP spokeswoman Kim Hughes.

Hughes said the remaining DWP site in the city that will need to be switched to chloramine is in the San Fernando Valley, at the Mission Wells groundwater facility that is used to store the local water supply.

She said this final project will help the city increase its locally captured water supply and rely less on imported water from the Metropolitan Water Department.

Hughes added that the water DWP purchases from the MWD have been treated with chloramine ever since the regional agency switched from chlorine in 1984.

The city’s Harbor area switched to chloramine early on in order to make it easier for MWD water to be mixed with that area’s local supply, according to the DWP website.

Chloramine is considered a milder chemical than chlorine, and has a less noticeable taste and smell, according to the DWP. The chemical is similar to chlorine in that it is also toxic to fish and when used in kidney dialysis, so the chemical should be removed in those instances using the appropriate methods.