But no one wants to drink brown water, and residents have lost faith in the district’s promises that the water is safe to use. To them, the problems at Sativa are just another example of the growing inequality they see across California.

The seamstresses, chauffeurs and domestic workers who live in Willowbrook, a community in the district that is primarily Hispanic and where 70 percent of residents speak Spanish at home, maintain neat front-yard patios where bright purple and yellow flowers bloom. But their roads are lined with potholes, vacant businesses are a common sight and many street signs are so faded they are difficult to read.

Although one in four residents here live in poverty, those who do not want to drink from their taps — which they no longer trust, even when the water is not brown — spend more money on drinking water than many families do in Beverly Hills, 20 miles away. Ms. Moralez, a home health aide, estimates her family spends about $150 a month on bottled water in addition to the family’s $67 monthly payment to the water district, which it still must pay. The family currently lives on a single income.

Anticipating another surge of brown water caused by the new construction this week, the county stockpiled huge amounts of bottled water to hand out to residents.

The distrust among residents was decades in the making, but there were few legal pathways for government intervention.

The district was issued various citations over the years, which were later enumerated in the state water board’s own October 2018 order taking control of the district, including for repeatedly failing to adequately test water quality.

Staff at the county commission that reviews municipal services began to raise alarms about Sativa’s management practices as early as 2005. By 2012, after another service review, the commission discovered that Sativa had not carried out any financial audits in seven years, and it began to push for the district to consolidate with another water utility, said Paul Novak, the executive officer at the Los Angeles Local Agency Formation Commission.