I lived the majority of ky adult life with a roommate who kept a 100 gallon salt water coral aquarium for almost a decade. One of the most expensive, difficult, time demanding hobbies I’ve ever seen. He couldn’t afford to replace the 20 or so gallon that needed to be replaced every couple weeks to keep the salinity and other chemical levels stable, so we had one of those under the sink RO filters. It always tasted great unless he forgot to change the filters. I worked at a Starbucks for quite a while and they basically just have a larger version of that which is changed out whenever the sensors ping their maintenance hq. Water there tasted the same.
Plastic bottled water to me is one of the ultimate fuck yous to the planet’s ecosystem that most people could easily stop today. It’s telling that the consumable plastic market is primarily owned by the oil companies, hell it’s one of the many products that can be developed from the refinery process. Short answer is get a metal thermos or canteen and refill it with RO or some other filtered water, get one of those Brita pitchers if you can’t or won’t install an RO, and cut back on your plastic containers as much as you feasibly can.