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?

http://www.wikihow.com/Make-Water-in-the-Desert

Why set up such an artificial scenario? If you really want to prepare for water shortage, then practice:
1. Storing it;
2. Using less of it;
3. Reusing it;
4. Reclaiming it;
5. Capturing it as rainfall.

I don’t know anything about your back yard, and whether you can dig for it, extract it from some plant material, capture it from dew, or what. So that’s the last place I’d work on this.

Rainwater catchment if there is rain. Condensation from morning dew if not.

Very legitimate concern. You wouldn’t just hate not having safe drinking water, you would soon die of not having it.

Check out a dew-catcher cloth. Works most nights, and does a bang-up job if it rains.

@ETpro where can I buy a proper dew catcher cloth?

@Ltryptophan I think you pretty much have to make your own setup. I don’t know of a place that sells them. In arid coastal areas of the Mediterranean, lots of homes have cisterns designed to catch rain and dew. There might be vendors for them there.

this seemed to work for them. Let’s see, where’s my moms tule…

So, I took an evian bottle, (oh, the irony!) and I cut it in two but left two upright elongated pieces of plastic. I made a square of aluminum foil about 6“x6” and put it diamond wise into the base. I dropped a honey tangerine in there to keep it steady. Then I stapled the aluminum to the plastic uprights. Then I poked some tiny holes in the aluminum. Now I wait. To be cont. ...

Invest in an air conditioner and save the water it discards.

@Ltryptophan That sounds like a rather small area to condense dew. I’m thinking something like a plastic sheet 6×6 feet would catch a bit of water. Let us know your results.

@ETpro in the morning the evian bottle was dry.

@Ltryptophan Yeah, I was thinking it would take more than one 6×6 inclined, slightly channel-shaped sheet to get a drinkable supply in anything short of a rain shower. On nights when the air is very dry and the dew point is extremely low, you probably get nothing.

You failed to mention the corner shop.

I don’t have a corner, or a shop there upon, in my back yard