Drink tank

When posting a sign indicating that the water obtained from a public source is not potable, you may want to keep in mind that the kind of person who would be trying to drink from that source in the first place probably won’t know what “potable” means, but will probably just slurmur* to himself, “Well, it don’ matter if it ain’t potable. I don’ wanna take it nowheres anyway.”
* Yes, I made up this word. You can figure it out. Just put on your drinking cap.