Chances are, you have a glass of water or a water bottle on your nightstand to drink with your medication, or in case you get thirsty before bed. After all, as water expert and America’s first water sommelier Martin Riese tells Yahoo Lifestyle, “Hydration is the key to everything, and it’s completely underrated.”
We know we need to drink a lot of water, but can the water you leak overnight really be drunk the next morning or even days later? Why does the taste of water seem to change overnight? Here’s what the experts have to say.
Why does water taste different when it sits for 24 hours?
Xi Chuanwu, a molecular microbiologist and microbial ecologist at the University of Michigan School of Public Health, told Yahoo Lifestyle that many factors can contribute to the stale, unpleasant taste of water overnight. Over time, the chlorine added to tap water to help disinfect it evaporates and changes the taste. Carbon dioxide dissolves in the water, lowering the pH and making it more acidic. Mineral content may also change.
Riese explains that water will always react to everything around it because it is a universal solvent. “It needs to smell and it needs to taste,” he says. For example, if you put a cup of boiling water next to your coffee, the next day the water will smell a little like coffee, even though it hasn’t touched anything. That’s one reason the CDC recommends not storing water near any cleaning products or chemicals, especially when it’s in a plastic container.
To keep your water tasting fresh, be sure to cover it with a lid or cover it with a glass to help keep out additional bacteria and reduce the amount of carbon dioxide dissolved in the water.
Can water go bad or expire?
Xi points out that as a general rule for tap water, it is not good to leave it in the pipes for more than a week. Tap water is not sterile and can contain water-borne bacteria such as bacteria, fungi and amoebae, which form biofilm barriers to water treatment chemicals (mainly chlorine and chloramines) and are more likely to grow when the water is stagnant in the pipes.
Storing water in containers for long periods of time can also lead to taste changes and regeneration of microorganisms in the water, says Chair. But storing water in a refrigerator helps prolong its freshness, rather than keeping it at or near room temperature, which can increase the chances of bacteria growing in the water.
The Centers for Disease Control and Prevention (CDC) recommends replacing any stored tap water, i.e., non-store-bought water, every six months – even under ideal conditions of 50 to 70 degrees Fahrenheit and out of direct sunlight.
For bottled water, Riese explains that most U.S. water brands have a shelf life of one to two years. But that’s more for the containers, especially those made of plastic, than for the water itself. That’s because when plastic bottles start to break down, chemicals leach from the bottles into the water.
Can old water make you sick?
Experts agree that old water contains more bacteria and can make you sick, although it does depend on the type of bacteria present and the health of the person drinking it. While your own bacteria are unlikely to cause any serious health problems, it’s the bacteria from sharing water bottles or glasses or touching other items like keyboards and doorknobs that are a real concern.
Finally, it goes without saying that “if you observe a difference in the color, smell or taste of water, it is best not to drink it,” Xi warns.
Does water last longer or taste better when kept in an aluminum water bottle?
Xi said aluminum bottles do not necessarily give water a longer shelf life or better taste.
Riese also explains that “aluminum bottles are more than just aluminum.” Water reacts with aluminum, so aluminum bottles usually have a thin layer of plastic or paint in the bottle as well.
The main problem here is that the epoxy resin lining in some aluminum water bottles may contain bisphenol A (BPA) that can leach into the water. The FDA still considers these bottles to be safe, despite numerous studies showing that BPA can cause health problems such as fertility, birth defects, type 2 diabetes, heart disease and cancer.
So what is the best reusable drinking water bottle?
Both experts agree that it’s best to store water in glass bottles with lids. Riese is a firm believer in glass bottles, “because glass doesn’t give anything to water or water, so it’s the perfect container for water.”
If you’re nervous about breaking a glass bottle, stainless steel is another good option because it’s corrosion-resistant and won’t leach chemicals like plastic.
How often do you need to clean your reusable water bottle?
As a best practice, Xi recommends washing water bottles at least once a day.
After drinking the same bottle all day, Riese says, “you’re going to feel like something’s wrong, that something smells or tastes off.” He even suggests is shaking your water bottle a few times throughout the day. That may sound like a bit much, but compared to using the same fork all day and not washing it – you probably won’t.
Now how much water do we actually need each day?
You will often hear that we need to drink 8 glasses of water a day. However, the CDC says there are no exact recommendations for how much water a person needs. A person’s water needs depend on many factors, including age, gender, weight, whether you’re pregnant or breastfeeding, how much activity you do each day and your overall health.
But in general, the National Academies of Sciences, Engineering and Medicine say the average woman needs about 11.5 cups of water a day and men need about 15.5 cups. It’s also important to note that as long as you eat a varied diet, about 20 percent of your water intake comes from food, such as fruits and vegetables.
However, the best way to tell if you are well hydrated is to check your urine. If it’s pale yellow, you’re probably getting enough water. If it’s dark yellow and has a strong odor, you may need to drink more water. Just be sure to use a clean water cup or bottle and cover it if you leave it out!