Four million people in central Chile were left without drinking water as torrential rain in the Andean foothills, since Friday, triggered landslides into the Maipo and Mapocho rivers.
This led to the fouling of the city’s water supply and forced the closure of the world largest underground copper mine, El Teniente.
The capital, Santiago was deluged after the Mapocho River overflowed its banks for the first time in 30 years.
The violent storms also caused widespread devastation across Uruguay with seven people killed and leaving more than 2,000 homeless.
A woman was killed by a landslide in the San Jose de Maipo valley, a mountainous region just south-east of capital, Santiago, while a special police force is searching for another four people in the same area, said Ricardo Toro, the head of Chile’s Onemi emergency office.
In Santiago, the national emergency response agency declared a red alert for the city of more than seven million people due to dirty water.
Television images showed streets in the upscale neighbourhood of Providencia overrun by flood waters after the Mapocho River breached its banks.
Heavy rains in the Andean foothills since Friday triggered landslides into the Maipo and Mapocho rivers.
The Intendant of Santiago’s Metropolitan region, Claudio Orrego, said late Saturday the cuts affect 4 million people, 1 million more than announced hours earlier.
Tap water production was down to 35 per cent of normal levels, said Eugenio Rodriguez, corporate manager of the Aguas Andinas water company.
Municipal authorities activated an emergency plan that includes accessing 45 backup water sources and mobilising more than 60 water trucks.
Thousands on Saturday flocked to stores to stock up on bottled water, and supermarket shelves were quickly left bare.
Aguas Andinas said that “it is not possible yet to estimate the time that service will be restored”.
The Office of National Emergencies called on residents to ration water, and collect and save water if possible.