Unless you live near a reliable source of water such as a stream or lake, you should consider harvesting rain water when the SHTF. As with stream or lake water, you will have to filter it. But if you have a good system, you can acquire all the water you need without ever having to leave home.
BubbleBeet made a short video explaining how he set up a 220 gallon rain barrel system. If a family of four went through 8 gallons of water a day, 220 gallons would still last almost a month. So even if it doesn’t rain for a while, you would still have plenty of water.
You can watch the full video below.