Prepping an emergency water supply at home, how many jerry cans is actually reasonable

This might sound a bit paranoid but after seeing some of the flooding news from earlier this year I decided it was finally time to stop putting off building a proper emergency water reserve at home instead of just assuming everything will always be fine, we live in an apartment in Dubai and honestly have zero backup water storage right now beyond whatever's already in the fridge, which in hindsight seems like a pretty obvious gap given how disruptive things got for some people during that period, so I'm trying to figure out a reasonable amount to actually store without going overboard and ending up with containers taking up space we don't really have room for in a smaller apartment, does anyone have a rough guideline for how much water per person is considered a sensible emergency reserve, because everything I've read online gives wildly different numbers depending on the source, some say a few days worth is plenty while others suggest planning for much longer disruptions which honestly feels excessive for city living where supply chains usually recover fairly quickly compared to more rural areas, while looking into containers I found some listings for reliable water jerry cans in Dubai stock which at least gave me a sense of typical sizing people go with for this kind of home storage purpose, does anyone know if there's a meaningful difference between using dedicated water storage containers versus just reusing something like large bottled water jugs, or is a proper jerry can genuinely worth it specifically for how it seals and prevents contamination over longer storage periods compared to something more casual, also how often does stored water actually need to be rotated or replaced to stay safe for drinking, because I don't want to fill containers and then forget about them for years assuming it's permanently fine without any maintenance involved, I don't want to overreact and turn our apartment into some kind of survivalist stockpile, but after seeing how quickly things got disrupted for people recently, having even a modest reserve seems like basic common sense rather than anything excessive, so if anyone's actually set up something similar for their own home, I'd appreciate hearing what quantity and setup felt right for a smaller household like ours.