Also, with regard to filling a bathtub (especially before a hurricane makes landfall), if there is soap film in the tub your water is not going to taste it's best. More worrisome is the fact that many tub drain stoppers leak. Even a tiny leak can drain the tub overnight.
I can say from experience (Hurricane Ian), a properly-maintained bathtub will hold water for a very long time. In my case, 3.5+ months before I finally pulled the plug because the water was just getting stale, even with pouring some bleach in it every other week. The tub water's for flushing toilets and other non-potable uses. We used water drained from the water heater for potable uses. Still filtered it with a Sawyer filter just to be safe. I've not used a bathtub bladder before, but it sounds like a good idea. It was 4 months before we had running water restored to the building, another 3 months before they got the jockey pumps installed to get water upstairs.
When disaster strikes, everyone needs the same basic essentials and there isn't enough to go around. You need at least a few days supply of food, water, and some spare gas for your car to get away from the madness. Get to where water and food are more abundant, then break out the portable water filters. Sawyer Squeeze is an affordable lightweight one. Have at least one per two people. If you're able to stay in your home, also have a gravity purifier like the Lifestraw Mission.
This. Portability is key. I never imagined that I'd be homeless due to a natural disaster. After all, my home was intentionally
built to handle a Cat 5 hurricane... and it did and kept everyone safe. BUT, the building's and island's infrastructure was wounded. The building was designed to handle a Cat 4 without damage, and has done so many times. A Cat 5 is a different story...it was designed to keep people safe and comfortable during such a storm, and still be repairable afterwards. Despite discussing this at length with the engineer and architects, the reality of the aftermath of such a storm never sunk in.