Ruling on rainwater

Q: Is it permissible to use the rainwater gathered in artificial ponds for purposes of Istinja' (cleansing the private parts with water after urination or defecation), Ghusl (ceremonial bath) and Wudu' (ablution)? Children swim in this pond and most likely urinate in it. Would the Prophet's statement, When water is more than two pitchers, impurity will not affect it be applicable to this case?

A: All Praise is due to Allah Alone and peace and blessings be upon His Messenger, his family, and companions. To commence: Water is pure in itself and can be used to purify unless its color, taste, or smell is changed by Najasah (ceremonial impurity).May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions. (Part No. 5; Page No. 74)