What everyone said isn't entirely accurate. In fact, the great circulation between sea routes is a system of "infinite" water circulation. The energy for the water cycle comes from the sun. When the sun is present, the water cycle continues. Of course, when the sun disappears, the water cycle stops. As the Sun still has 6 billion years to live, we can consider the water cycle on Earth to be “infinite”.
I don't know if LZ is satisfied with this explanation