Uruguayans in the capital Montevideo are praying for rain amid a historic drought that has left the city’s main reservoir with only ten days of water left. 

Low rainfall and high temperatures across the southern region of South America have triggered a severe drought over the last year, affecting crops in neighboring grain producer Argentina and triggering steep farm losses.

The water deficit is the worst Uruguay has suffered in 74 years, according to officials. It is affecting supply to thousands of households and leading to poor water quality.

“I’m worried that we’re relying on rain as the only answer,” Vanessa Fleitas said outside her child’s school in Montevideo that had closed early because of a lack of drinking water for the students. “It is unusually warm for the time of year.”

Water levels in the Paso Severino reservoir, which serves more than half of Uruguay’s 3.5 million people, are at “historical lows”, according to state water company Obras Sanitarias del Estado (OSE), at around 10% capacity.

The latest data shows it has close to 6.2 million cubic meters of water, a far cry from the 60 million monthly average. Around 650,000 cubic meters is needed daily to supply the capital.

Light rainfall in recent days “did not change the outlook,” OSE said, although some showers are forecast for later this week. Meteorologists say it would take 50 millimeters (2 inches) of rain every day of June for reservoir levels to start to recover.

Dwindling reserves of freshwater in the country’s main reservoir forced the public water company in late April to mix supplies with water from the River Plate estuary, resulting in unusually high levels of sodium and chlorides.

“My customers don’t trust what comes out of the tap,” said shopkeeper Ramon Arteaga in downtown Montevideo, where daily sales of bottled water at his store have increased tenfold since the start of the water deficit.

Public anger over water shortages is building with street demonstrations planned in the capital on Wednesday. 

Federico Kreimerman, president of the workers union at OSE said low rainfall, mismanagement of supplies and a lack of state investment was to blame. Water for human consumption also competed with soy farming, ranching and forestry, he added.

The office of the president declined to comment. It has said it is assessing additional measures, including a new reservoir to reduce the salinity of local drinking water.

-Reuters