Itís not the water Iím worried about
Barfblog by Doug Powell, May 23, 2018
The situation that Life Hackerís Nick Douglas presented to me was (Iím paraphrasing here slightly): hey, Iím gonna leave a glass of water out over night and I know itís not going to be a problem after a couple of hours, but I canít leave that water there for a few weeks can I, because it will go bad, right?
My answer (paraphrased as well) I guess it depends what you mean by bad. The water will probably taste different the longer it sits there. Yeast, mold and algae might float into it, but as far as pathogens go, my take is that itís really low risk.
I told him that the water wasnít the issue, itís what gets introduced to the water like food debris or some other nutrient source. And then a pathogen. Or poop. Poop has both.
My quote was, ĎWhat would matter is if, like, someone had poop on their finger and stuck it in there.í
Itís not like I thought water rots, OK? I just thought that thereís enough bacteria floating around a home, or in tap water, or on your lips when you take a sip, that given a month alone in a glass, it might grow and then make you sick. But, as food safety specialist Dr. Benjamin Chapman tells me in a mildly embarrassing phone call, it wonít.
But there must be some way it could, right? Yes, Dr. Chapman says, if you didnít wash the glass properly, and left a nutrient like juice or other sugary remnants.
But even if youíve drunk out of the glass, getting your mouth on it, leaving a lip print, and then leaving out the glass ó even then, he says, youíre not going to poison yourself with your own mouth bacteria.
Obviously, if the water supply is contaminated, all bets are off. If it was toxic when it left the tap, itís still toxic after sitting out. But apparently, as long as it started out fine, even super-gross-tasting old water is healthy to drink, and Iím an ignorant hydrophobe. Fine. But Iím not alone. I only got curious because cooking blog The Kitchn asked the same question ó or maybe they were stating the obvious for rubes like me.