“Most experts will tell you tap water has a shelf-life of six months,” Satterfield says.
Water that has been held in your water tank or water pipes for any longer than 24 hours will deteriorate and will become stagnant due to loss of chlorine residual, warming and interaction with the plumbing system materials.
It is okay to drink water left overnight as long as it is sealed or closed properly. You can still drink water from a water bottle after a week if the bottle is clean and does not show any signs of mold build-up. However, the stock water in an open glass or bottle should not be consumed the next day.
The packed bottled water is good to drink by the recommended manufacturer's expiration or best by date. If your water bottles don't have expiration dates, a good rule of thumb is to drink them before they hit the two-year mark.
As far as the safety issue, Munchies points out that water doesn't have any “sugars, fats, or proteins that can rot or go rancid,” so it didn't “go bad” after several hours, despite the weird flavor.
Germs especially like to live and grow in water when it is stagnant (not flowing) or when it is not treated with enough disinfectant, like chlorine. It is important to know where your tap water comes from and how to safely use it for purposes other than drinking.
When you leave the glass of water uncovered for about 12 hours, carbon dioxide in the air starts to mix with it. This reduces the pH level of the water and gives it an off taste. But even then this water is safe to drink. Moreover, most experts believe that tap water has a shelf life of six months.
Although properly stored public-supply water should have an indefinite shelf life, replace it every 6 to 12 months for best taste. If the water you are storing comes from a private well, spring, or other untested source, purify it before storage to kill pathogens (see below).
Despite the off-taste of both plain and carbonated tap water, they are considered safe to drink for up to 6 months. All you need to do to keep water healthy and drinkable for at least 6 months is store water in a cold, dry and dark place where the sanitization can also be maintained.
“Most experts will tell you tap water has a shelf-life of six months,” Satterfield says.
Long-Term Water Storage Solutions
The general guideline is to use food-grade plastic bottles. You can also use glass bottles so long as they haven't stored non-food items. Stainless steel is another option, but you won't be able to treat your stored water with chlorine, as it corrodes steel.
Replace stored water every six months. Keep stored water in a place with a cool temperature (50–70°F). Do not store water containers in direct sunlight.
As water sits out, small amounts of carbon dioxide dissolve into the water. This forms carbonic acid, which may lower the pH just slightly. Tiny amounts of other gases, like acetone and aldehydes, may dissolve in, too.
Some of the more commonly reported problems experienced from drinking impure water include, but are not limited to, the following waterborne illnesses: Gastrointestinal Problems. Diarrhea. Nausea.
“It's pretty much just your own germs [on and in your bottle], so there's not much to worry about,” Gerba says. “Yeah, you'll get a lot of bacteria because there's always wash-back, but basically it's the bacteria that's in your mouth anyway, so we've never really seen it as an issue.”
A: Water is not recommended for any infant under four months of age. Although a small amount of water every now and again may not hurt, too much water can cause changes in the electrolytes in a babies bloodstream which could lead to seizures and death, so it's best to not give any at all.
The bottom line. Tap water can be stored safely for up to 6 months. Certain chemicals found in plastic can leach into bottled water over time, which could potentially damage your health. Thus, it's probably best to avoid commercially bottled water that's far past its expiration date.
Babies under six months should only drink tap water that has been boiled and cooled down. Water straight from the tap is not sterile so is not suitable for younger babies. Once your baby is six months old, you can offer them water straight from the tap in a beaker or cup.
Germs and other contaminants are found in rainwater.
While useful for many things, rainwater is not as pure as you might think, so you cannot assume it is safe to drink.
Bacterial growth occurs in noncarbonated natural mineral waters a few days after filling and storage at room temperature, a phenomenon known for more than 40 years.
If the kettle is clean and dry, you pour water as soon as removed from the heat source, filled up to the brim, it will be potable for at least 2–3 days.
✅ Is it safe to drink old bottled water? The FDA does not require a shelf life on bottled water but plastic bottles can leach hormone like chemicals that increase over time. Always choose BPA free bottled water to mitigate the risk of toxic chemical exposure. The recommended shelf life of still water is 2 years.
After around 12 hours, our tap water can go flat as the carbon dioxide in the air mixes with the water. This lowers the pH level of the drinking water, and this process imparts a stale, lifeless taste. Although the drinking water is still safe to drink, it's less palatable, and many people won't enjoy the taste at all.