As Yenny Gonzalez crouches to fill a bucket from a jet of natural water flowing from a hillside on to a pot-holed road at the edge of Caracas, she admits it may not be the most convenient source of water, but at least it's reliable.

That is more than can be said for the city's public water system. Venezuelans in the capital are bracing themselves for drastic rationing as public services in the oil-rich nation sink ever deeper into crisis, threatening to undermine President Hugo Chávez's support.