You can usually tell if the water in your bottle is going bad / filled w bacteria..
If this is not possible, take in mind that your immune system can take care about bacteria. In 99% of the cases after a learning period, local bacteria will stop being a problem. Unless your live in areas with very unsafe water sources or particularly dangerous organisms this shouldn't be a main factor in the choice.
> If you have been drinking water that has been constantly stored in copper bottle or vessel, chances are high that you might be at the risk of copper toxicity. It can cause severe nausea, dizziness, abdominal pain and can result in liver and kidney failure.
No thank you. I get the struggle to not use plastics, I try to avoid it myself too (especially buying water in plastic bottles in shops is something I never do), but alternatives are subpar, either very heavy, fragile and overall impractical for outdoor sports (ie glass), or some other issues. What happened to stainless steel? Heavy but at least should be inert and nearly indestructible, no? I mean those without some crap BPA lining inside, like thermos but single walled.
(For some hints, see the sketches of the Dwarven Kama Sutra found in JRR Token’s estate)
Why is copper better than stainless steel?