@Jasper19And him Generating water ^^
Hydrogenesis: Percy can create water from his own power, though it takes much of his energy for him to do so. Percy did this while at Mount Saint Helens, creating water out of nothing to cause a volcanic eruption, which was powerful enough to cause half a million people to evacuate, and caused ash to fall as far as Lake Tahoe and Vancouver. He also uses this skill while creating his own personal hurricanes. While traveling on the Argo II during The Mark of Athena, he presumably used this ability while combining his powers with Jason Grace's to create powerful storms.