This post has been removed as an example of a "throughout history" question, which is prohibited per subreddit rules. Do repost if there is a particular region and timeperiod of interest. Also, it would help greatly to add some context to what is meant by "distributing drinking water", since water is available in most places... are you thinking of a particular city or scenario (like a siege)? BTW, depending on what you're looking for, this section of the FAQ may be helpful