Is There a Difference Between Bottled Water and Tap?

This article is an excerpt from Sports Nutrition for Endurance Athletes by Monique Ryan MS, RD, LDN, CSSD. In her comprehensive guide to sports nutrition, Ryan uses her 30 years of experience coaching professional and age-group athletes to simplify this complex subject into proven, real world guidelines. Sports Nutrition for Endurance Athletes shows runners, cyclists, and triathletes how to address specific nutritional needs for short- and long-course racing and busts dozens of myths and misconceptions along the way.

Does it really matter where your water comes from?

Americans currently consume more than 9 billion gallons of bottled water per year. In recent years the bottled water industry has taken a hit for the landfill problem that plastic bottles generate and recent reports indicate that bottled water is not necessarily safer than tap water.

Tap water does contain substances other than water. Depending on where you live, it can provide varying levels of minerals such as fluoride, calcium, sodium, magnesium, iron, zinc, lead, and mercury. While calcium and fluoride may be beneficial, lead and mercury are not. As a health-minded athlete and consumer, you may also be concerned about microbial contamination and pesticide residues in water.

Unlike bottled water, tap water is regulated under the strict standards of the Environmental Protection Agency (EPA), but there are some contaminants that the EPA does not regulate. Your local water municipality is required to supply you with an annual “Right to Know Report” every July. This report lists contaminants detected in your drinking water and notes any violations that have occurred in the past year. Your water provider is also required to test for microbes several times daily. You can contact your local water municipality to obtain the names and numbers of certified testing labs to have the water from your tap checked. Levels of lead and copper in your water may be higher than official reports indicate because of deterioration of household plumbing and faucets.

For healthy adults, tap water in the United States is a very safe option, but that doesn’t mean that you can’t make your water safer. If you discover that your water is not of the best quality, filtered water may be a viable option. Many filters attach right to the tap and can filter out lead and other contaminants. Another convenient filtering method is a pour-through filter that can be placed in a special pitcher and kept in your refrigerator. More expensive filters include an under-the-sink model that requires a permanent connection to your water pipe. Reverse osmosis filters are considered the best of this type and can filter out lead, mercury, minerals, some pesticides, and microorganisms. Whole-house filters are the most expensive and are installed where the water meets the main water pipe. The benefit is that this type covers all the water used in the house.

An independent organization called NSF International sets standards for and certifies water filtration systems. Its website,, lists filters and the contaminants that each is certified to reduce in your water. Look for a filter with a pore size of less than 1 micron in diameter. Be sure to follow the manufacturer’s directions for replacement of the filter cartridge.

Because it is convenient to have a portable water supply when commuting and working, carrying a reusable bottle filled with tap water is a great solution. You won’t have to pay for bottled water or toss the bottle when finished. Just make sure that you wash your bottle daily with hot, soapy water to keep it safe from bacteria. You can even purchase stainless-steel bottles that do not contain unsafe components found in plastic bottles.

Should you determine that bottled water is a more convenient option for you, understand there is no guarantee that it is microbe-free or safer than tap water. About one-quarter of all bottled water comes from municipal water supplies. Bottled water can also be spring water, mineral water, well water, or distilled water. Unlike EPA-regulated tap water, bottled water is regulated by the Food and Drug Administration (FDA). It is not tested for the parasites cryptosporidium and giardia, and it is tested only once weekly for microbes. It is convenient, however, and many consumers like the taste of certain brands.

Look for brands of bottled water that maintain the NSF International certification. To do so, water bottlers must send daily samples for microbial testing to an independent lab and maintain records of filter changes and other quality checks. You can also determine if your brand of water is NSF-certified by visiting the NSF’s website.

Think before you drink:

        • Drink only 100 percent fruit juice, and know your limits. One 4-ounce serving supplies 60 calories for most juices. Look for vitamin C sources and even calcium fortified drinks.
        • Use low-fat milk whenever possible.
        • Order coffee drinks with fat-free milk and skip the whipped cream. Request sugar-free syrup for coffee drinks or ask for fewer pumps of regular syrup.
        • Beware of frozen coffee drinks and other choices that resemble milk shakes. Aim for the “skinny lattes.”
        • Smoothies can range from 200 to 800 calories per serving. Choose the lower-calorie versions and smaller portions.

See what to eat and when with Sports Nutrition for Endurance Athletes. Ryan demystifies optimum daily nutrition and shows simple steps to make the best decisions about what you eat and drink.