In Plague, Little Pete creates a rain cloud that provides infinite water to Perdido Beach. He does this when he is really hot and thirsty from the death cough that spreads the FAYZ in Plague. It stays after he dies in the end and supplies the water, saving the lives of everyone (before they had a limited water supply, that is why they had to move to the lake). To create the cloud, he had to destroy the whole roof of the first floor of the house he shared with Astrid.
Many kids were showering in the rainwater before drinking the same water until Albert put a stop to it.