Suffering from headaches? Drink more water.

Feeling tired? Drink more water.

Fighting the flu? Drink more water.

Trying to lose weight? Drink more water.

As pediatricians, we advise our patients to “drink more water” all the time — a recommendation that sounds so simple, yet so often under-recognized. In fact, more than half of American children do not drink enough water and one-fourth do not drink any water on a daily basis. Keeping hydrated is important for nearly every system in the body, from blood circulation and nourishment to temperature regulation and waste removal (after all, the human body is made up of 60 percent water). It’s no wonder that dehydration, even at mild levels, is associated with a host of symptoms that may have significant impacts on physical and mental health. So, while we don’t usually think of water as medicine, we would argue that water is as good as any drug on the market.

With regards to the type of water, we prefer that all our patients drink water from the tap, even newborn babies with formula. For one reason, tap water is free. Instead of spending a premium on something that is already available from faucets and fountains in most homes, schools and parks. That extra money could be better invested elsewhere — for example, our children’s college fund. If we were to simply switch from drinking bottled to tap water, we would save $720 each year — that is assuming we drink the recommended four 16-ounce bottles per day ($0.50/bottle x 4 bottles/day x 30 days/month x 12 months/year = $720).

Another reason to drink from the tap is for the environment. Bottled water production requires 2,000 times more energy than tap water production. Additionally, most plastic bottles end up in landfills and oceans, where it may take 500 years to break down while gradually leaching harmful toxins into the surrounding water and soil. Since many families have already chosen to go green by using reusable grocery bags or buying locally sourced foods, switching to tap water can be another easy way to help out the environment.

The final, and perhaps most important reason to drink tap over bottled water is safety. After what happened with the lead-poisoned water in Flint, Michigan, we understand why parents are skeptical of the municipal water system. However, tap water in the U.S. is actually tightly regulated by the Environmental Protection Agency, forced to undergo a series of disinfection and filtration steps to ensure that the amount of impurities does not exceed a legal “maximum contaminant level” by the time it reaches us. Bottled water, on the other hand, undergoes less testing and may, therefore, be less safe. Although it is true that tap water in some parts of the country are contaminated, outside of natural disasters and few rural areas, this is rare. The Flint water crisis in 2016 was an unfortunate and inexcusable event caused by the government’s negligence and improper treatment of the drinking water after the city’s water source was changed.

Given all the mixed media coverage and endless advertisements on the different types of water, we realize that this topic can be confusing, even controversial at times. So, we’ve tried to sum up water and health in three simple rules: Drink more water. Mostly tap. Sometimes filtered.

1. Drink more water. As a rule of thumb, children should drink a number of eight-ounce cups equivalent to their age, with approximately eight cups per day for children eight years old and up. Adults should drink at least eight cups of water per day. Everyone should drink from reusable stainless steel or bisphenol A-free plastic bottles to protect the environment.

2. Mostly tap. Tap water remains the most cost-effective, convenient and eco-friendly way to stay hydrated. It also has the added benefit of containing fluoride to prevent tooth decay. While tap water may contain trace amounts of impurities, in our opinion, it is not worth worrying over because of how little that actually exists. For families who are concerned about tap water safety, testing kits and water quality reports are publicly available to provide information about potential chemicals in the city’s water.

3. Sometimes filtered. If certain chemicals, like lead, are found to be above the “maximum contaminant level,” a water filter should be used. Luckily, because fluoride is a very small molecule, it does not get removed in most common household water filters. The “taste” of tap water may also be enhanced by filters because the chlorine is reduced.

Alvin Chan is a pediatric gastroenterology fellow. Kim Ramirez-Chan is a pediatrician.

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