1) Fresh water: normal, size-based water filters, boiling, or tablets may not be enough because flood waters contain dissolved chemicals and sewage that is not filtered out and cannot be killed like bacteria/viruses
2) Without quick emergency response you should have the tools and knowledge to deal with major bleeding, blocked airways, and hypothermia as these are preventable life-threatening situations.
3) Phones, reflectors for daytime, and a flashlight for night will help you get rescued as soon as possible. A fold-out solar charger is a great way to make sure you can call for help, and contrary to popular belief they DO work even when it's cloudy. LPT: Putting your phone in a waterproof phone bag and filling it with air will make it float on top of the water while still being able to use it.
Source: http://ift.tt/2w3SY1i