Ok. I just filled up three containers. What happens if pipes burst and toilets overflow?
You need at least one gallon of water per person or small animal per day, more if you intend to be physically active. The rule used to be have enough for three days - I'd have enough for a week or more now. This one's *big*.
Pipes shouldn't burst. If the water cuts off, go dig a latrine outside, away from your home.
Push comes to shove - you can always dig a temporary latrine/trench.
Probably won't happen. If it does, cut off the water at the meter.
and toilets overflow?
You will have a mess to clean up. Any carpet can actually be cleaned and disinfected; you might want to replace the padding. You will need a mop and a shop vac. Be sure to mop the slab with some Clorox while you have the carpet up. After you clean the carpet, you might want to leave it out in the sun for a couple of days.