Okay, here’s the exception that makes this whole conversation worthwhile: if you opened the bottle and then dipped a dirty spoon in it (like a monster), you’ve introduced bacteria. Now you’re not storing distilled water; you’re storing a hostage situation. In that case, put it in the fridge to slow microbial growth, or just toss it unless you enjoy playing Russian roulette with your gut.
Also, if you’re using distilled water for baby formula (yes, some people do), the CDC recommends you refrigerate the mixed formula—but the water itself? Nope. Just keep it in a cool, dark cabinet like a vampire’s teatime stash.
Does Distilled Water Need To Be Refrigerated Once Opened? - Survival
The Ultimate Pro Tip (Ignore at Your Own Peril)
Label that jug with the date you opened it. If it’s been two years, don’t drink it—not because it’s dangerous, but because you should respect your own timeline. Distilled water doesn’t expire, but your dignity does when you’re drinking from a dust-covered container from 2019.
I once found a jug of distilled water in my grandmother’s basement that was officially older than my cousin’s child. I opened it, smelled nothing (because, duh, it’s water), and poured it into her humidifier. The humidifier didn’t file a complaint. So, feel free to be reckless, but maybe don’t serve it at a dinner party.
