Artist, William Tasker. Federal Art Project, Silkscreen, circa 1941/3. Source
I found this image on Pinterest. It's one of the things I enjoy about Pinterest - finding great images, even if people don't source them well, grrr.
This one caught my eye not just for the great graphic but because the message seems so awkward now. It was made to remind/convince people to conserve water for the war effort. That's the "guns." Government wartime propaganda.
But as a viewer in 2012 I read it as, No Water, No Guns....don't waste it. That is, there is no water and no guns....therefor don't waste these recources. Which brings to mind some dystopic sci fi movie, or contemporary news and activism about water as a resource. Big topic. Water. Resource. Or did it mean, War over Water...another dystopic story -in- the making.
It only took me a minute to remember to adjust my time frame to World War 2 to realize that the idea of conserving water for the wartime/militarizaion effort would be common enough that the poster made sense immediately.
It's also possibly true that it's just not that well written enough to telegraph it's meaning. I can't tell from here.