Drought-pummeled lawns across Los Angeles County will be a little bit thirstier for 15 days in September when officials suspend outdoor watering in several areas to repair a leaking pipeline, the Metropolitan Water District of Southern California announced Monday.

The emergency repair will shut down the 36-mile Upper Feeder pipeline — which delivers water from the Colorado River to Southern California — from Sept. 6 to 20, the MWD said. The leak was discovered this year, and the pipeline has been operating at reduced capacity under a temporary fix while officials designed a more permanent solution.

“We need to make this urgent repair to ensure this infrastructure can continue serving Southern California in the immediate term and for years to come,” MWD Water System Operations Manager Brent Yamasaki said in a statement. “While we do this work, we need people who normally get water from this pipeline to eliminate their outdoor water use to stretch the limited available water supplies.”

The latest maps and charts on the California drought, including water usage, conservation and reservoir levels.

More than 4 million people will be affected by the shutdown in cities including Beverly Hills, Burbank, Glendale, Long Beach, Pasadena, San Fernando and Torrance, as well as areas served by the Central Basin Municipal Water District, Foothill Municipal Water District, Three Valleys Municipal Water District and West Basin Municipal Water District, the MWD said.

The agency is asking affected residents to eliminate all outdoor watering during the shutdown and to be cautious about indoor use by limiting showers to five minutes or less, among other water-saving measures.

“We don’t take this call lightly, but it is what is needed at this time,” Yamasaki said.

Agency spokeswoman Rebecca Kimitch said the shutdown is not related to critical drought conditions on the Colorado River, which is shrinking to new lows due to climate change and chronic overuse.

Lake Mead, the nation’s largest reservoir, which is located along that river, was at 27% of its capacity on Monday, but the seven states dependent on the river have failed to come up with a plan to drastically reduce their use.

Right now, “this is about a shutdown on a leaky pipe,” Kimitch said.

Two months ago, federal officials told states that depend on the Colorado River to make plans for major cuts. Negotiations have yet to produce a deal.

The Colorado River is one of two major sources for the MWD, which provides water to more than two dozen agencies in Southern California.

Residents reliant on the agency’s other primary source, the State Water Project, are already under reduced watering limits and are being asked to maintain those schedules during the shutdown. That includes two-day-a-week outdoor watering rules for areas served by the Los Angeles Department of Water and Power.

The MWD provided the following guidance for areas affected by the upcoming shutdown:

DURING THE SHUTDOWN (Sept. 6-20)

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Hayley Smith covers trending and breaking news for the Los Angeles Times. She previously contributed to The Times’ COVID-19 project, “The Pandemic’s Toll: Lives Lost in California,” in partnership with the Pulitzer Center and USC. She holds a master’s degree in journalism from USC.