Something to keep in mind in certain disasters: The water supply can become contaminated by flooding, chemicals, sediment. Ideally, in such possibilities, don’t drink unboiled and unfiltered water and don’t give it to animals.
Public water agencies constantly test water supplies and will sometimes send out warnings to boil water and let it settle before ingesting it, but it can take them time to do that. You don’t want to make anyone sick before then.
In the U.S. and various other countries, many homes have barbecue grills and such. It’s possible to use them to boil water with a pot or kettle even if the normal indoors way of cooking isn’t working. You also can ask HOs if they have camping supplies you can use in a jam. That can include sleeping bags, camp stoves, Sterno. Many campers know that huddling in sleeping bags with pets can keep them warm even in very cold conditions.
If it gets super cold and other methods don’t work, you might consider getting into a car and pulling it into the garage. With the windows rolled up, you’ll be in an enclosed space that can be heated up with say a candle — just be careful with any open flame. (Folks who live in freezing conditions often know to do this if they’re stranded in their car on the road — it can mean the difference between staying alive or freezing to death.) Just don’t run the engine, so you don’t end up poisoning yourself and a pet(s) with the fumes if the car is in the garage.
Indoors, you can also consider pitching a tent or a makeshift one, or getting into a closet to sleep. The smaller the space, the easier it is to stay warm, especially if it doesn’t have windows.