Hi Sam, you might check with the county about again rain water you can get. If you can you can make a on the ground roof to catch rain water. Go to youtube and check out living in a tiny box. He used four 2,500 gallons (news one ) but you can find them used on Craigslist. I live in golden valley,az, there some for sale for as little as $400.00. If you look around and on Craigslist you could find the sheet metal. You could also sink a aboveground pool for water storage, a 15 foot pool holds up to 4,400 to 5,000 gallons. You need to keep it covered. Also you could use a pond liner and keep that covered. Pond liners are about 18 to 20 mill, pool start at 25mill. Again you can find used pools at the end of summer on I know, I know craigslist.but first get to know the lay of the land. Do you have any washes on your ( more free water ) , I have a wash that gets about 3 to 5 million gallons of water each year , free! And that in the desert. I'm only asking for 30,000 gallons. Even I could say what desert.