Starting on Thursday, nearly 140,000 customers of the Puerto Rico Aqueduct and Sewer Authority, including some in San Juan, the capital, will be without running water every other day, the utility announced on Monday.

Public health experts have repeatedly cited frequent hand washing as key to curbing the coronavirus spread. Puerto Rico has reported 7,250 confirmed and probable coronavirus cases and 153 deaths.

“We are aware of how necessary water is as a resource in the Covid-19 pandemic, which is why it is important to continue hygiene measures to protect families,” Doriel Pagán, the executive director of the Aqueduct and Sewer Authority, said in a statement. She added that the utility does not know how long the rationing measures may last.

Gov. Wanda Vázquez declared a state of emergency over the worsening drought conditions. Of the island’s 78 municipalities, 21 are in a severe drought and 29 in a moderate drought, Ms. Vázquez said.

Earlier this month, other water rationing measures were imposed on more than 16,000 customers in northeastern Puerto Rico. The most parched area is the island’s southwest, which is still recovering from a 6.4 earthquake in early January.