Once again, you'll need written assurance from the manufacturer. Of course, walking is a healthy alternative. If you live in a rural area, horses and carts might be an option. Another aspect may be unavailability of fuel. Gas stations may experience a variety of electrical or electronic problems, as well as delays in fuel delivery.
Storing gas can be extremely hazardous.
We don't recommend it. A normally active person needs to drink at least two quarts of water each day. Hot environments and intense physical activity can double that amount. Children, nursing mothers and ill people will need more.