Sorry for my poor English, not my mother tongue... Well, in debate terms: let's say you could decide to add element to tap water because locally you state "the

Sorry for my poor English, not my mother tongue... Well, in debate terms: let's say you could decide to add element to tap water because locally you state "there are not enough of this element", how can you dose it? Some do not drink tap water, will get nearly none, some drink much, some came here for a bit of time coming from other places, ... Teaching people a good diet it's a thing, "imposing" adding stuff to common goods is a dangerous choice, which could be well abused to do very nasty things.