Depending on the scale of your growing spaces, free water can be gathered by just leaving out a bucket/open container outside to collect rainwater. Rain is generally plenty during my growing season but I have a few placed containers to capture rainfall. If needed, I can dunk a small bucket into these sources to bring the water to the nearby plants.
I'm proud to say this season that I did not turn on the hose bib once, I either let the rain do the work or I hand watered from these sources. It takes a little bit more time, but it is pleasurable work.