Without using modern plumbing, or water in a ditch, how can I get up to a liter of clean drinking water from my back yard by tomorrow morning with minimal effort?

This is practice runs for water scarcity in my lifetime. I am trying to train myself to be ready for hard times before I ever see them. I don’t think I necessarily ever will, but I don’t want to see them unprepared. Water is one of the things that I really cherish. I would hate not having it as I am sure you can imagine, so tonight I wanted to see how much water I could get from the yard. Suggestions?