The Vatican is turning off its 100 fountains in response to a prolonged drought following Italy's third-driest spring in about 60 years.
Vatican spokesman Greg Burke said it was the first time they could remember being forced to turn off all the Holy See's fountains.
The two Baroque fountains in St Peter's Square, by 17th-century sculptors Carlo Maderno and Gian Lorenzo Bernini, have already been turned off.
Rome is gasping after 72% less rain than normal this month, 74% less in June, and a 56% reduction from the long-term average across March, April and May.
The authorities in Rome have already closed drinking fountains and are now considering water rationing.
Caring for the planet and its resources is an important issue for Pope Francis, who demanded swift action by world leaders in the first ever papal document dedicated to the environment.
"This decision is very much in line with the pope's thinking on ecology: you can't waste and sometimes you have to be willing to make a sacrifice," the Vatican spokesperson added.