In my part of the country, Central Texas, rainfall in the hot summer is very low. I guess we could be classed as semi-arid. I've seen Arizona, New Mexico and Nevada and they are definately arid. But annually here it is around 36 inches and while less than many other areas is quite adequate if managed. However, it quits raining completely from about the middle of June through September unless a tropical storm brings rain from the Pacific ocean across Mexico to us. And during hurricane season on the gulf coast, occasionally a hurricane will come inland and bring rain 150 to 200 miles inland including my area but this is rare, too. To drill or dig a well for water is prohibitively expensive since it is several thousand feet down. But what has very successfully been done by many is rain water harvesting. This employs a system of storage of rain water in tanks or cisterns. The water is gathered or harvested from rooftops by means of extensive guttering that channels the water into the tanks. I have just started this process on my place and have just bought the first of 4, 3,000 gallon poly tanks. If all tanks are full, that is 12,000 gallons mainly for watering gardens. These tanks cost about $1,000.00 each. After getting all 4 of them placed and integrated into the system we may get more if we feel we will need them. Our first test came last week of how much water can be gathered like this. With only the one tank in place we were not expecting any rain and had suffered through 12 days in a row of 102 degrees thru 108 degrees. Suddenly a nice rain cloud came over us and we got nearly 4 inches in 2 hours. The tank had beens setting there empty but that rain filled the tank to about 800 gallons! This was a great test of how well rain water harvesting works even in a place like this. We also want to employ drip irrigation lines and other arid region type watering systems to mete out just the amount we need and not waste any. It would be great to have enough storage to run the house and water the gardens and yard and we may do that.