Cuba is facing its worst drought in half a century, with tens of thousands of families almost entirely reliant on water trucks for essential supplies.
The drought started two years ago, and reservoirs are now down to a fifth of their normal levels.
The government is providing road deliveries of water to more than 100,000 people in the worst affected areas of the capital, Havana.
The situation in Havana is compounded by a pipe network in poor condition.
The state-run newspaper Granma says up to 70% of water pipes supplying the capital are leaking and in urgent need of repair, the BBC's Michael Voss in Havana says.
Residents are having to use buckets and bottles to fill up with water from the road deliveries.
"It's completely out of control," one resident, Ana Gomez, said. "Just imagine that you can't wash when you want to, you have to wash when you are able to."
Another, Enrique Olivera Gonzalez, said: "As there is no water, you can't wash your clothes, cook, or clean your house."
Cubans are hoping the rainy season in May and June will bring some respite.
But even a normal rainfall will not be enough to fill up the reservoirs, our correspondent says.