It is when you are wealthy and healthy!
As Narrated by Abu Huraira r.a:
A man came to the Prophet (ﷺ) and asked, “O Allah’s Messenger (ﷺ)! Which charity is the most superior in reward?” He replied, “The charity which you practice while you are healthy, niggardly and afraid of poverty and wish to become wealthy. Do not delay it to the time of approaching death and then say, ‘Give so much to such and such, and so much to such and such.’ And it has already belonged to such and such (as it is too late).”
Reference: Sahih al-Bukhari 1419
Abraham Maslow suggests: Lower level needs (for survival and security) have to be met before people take action to meet higher-level needs.
A Theory of Motivation (1943)
Clean water is a source of survival and security, you may be part of the reason for helping the Ugandan or Rohingyan community in achieving greater heights!