Original Text
For the waters are for those who dwell on the earth; for they are nourishment for the earth from the Most High who is in heaven: therefore there is a measure for the rain, and the angels take it in charge.
Simple English
The waters are for the people living on earth, as they provide nourishment for the earth, which comes from God in heaven. That's why there is a limit to the rain, and the angels are responsible for managing it.