You drink two to three litres a day of whatever is in the tap, the bottle, or the fridge dispenser. If any of that is off, whether chlorine, plasticiser, or warm plastic, you are dosing a thousand times a year.
Defensible baseline
Under-sink or gravity filter that handles chlorine and heavy metals. Glass or steel bottle. Cold-store in glass. That is 90 percent of the work.
Spring water in glass is an upgrade if you can get it steady. Anything that lived in a warm plastic bottle for a week is worse than the tap it came from.
Salt is part of it
Clean water without minerals is not neutral; it pulls electrolytes out. A pinch of unrefined sea salt in the first glass of the day, and again mid-afternoon, is enough for most people who move and sweat normally.
