Bottled water is the most popularly consumed drink in the country, according to the Environmental Protection Agency. Those in support of bottled water claim it's convenient, safer and better-tasting than tap water. Those in support of the tap point out potential contaminants, increased cost and potential exposure to plastic-based chemicals as reasons to avoid bottled water. If you choose bottled water, you're likely to be safe, but you should know about a few potential side effects.

Contamination

Tap water and bottled water may both contain small amounts of bacterial, fungal, mineral and other contaminants, according to the Environmental Protection Agency, or EPA, but there may be a slight chance that bottled water contains more contaminants. Tap water is regulated by the EPA to make sure it meets strict guidelines for safety. Bottled water is regulated, too, according to the EPA, but it's regulated as a packaged food product by the Food and Drug Administration. Bottled water companies have to test their products on a regular basis to make sure they don't contain dangerous contaminants, but the testing and recommendations aren't as stringent or strictly enforced as tap water's are. On top of that, reuse of plastic water bottles can lead to increased bacterial contamination if they're not properly washed. Still, the EPA considers both water sources safe for human consumption.

Lack of Fluoride

Fluoride exists naturally in tap water, according to informational website Kids Health, and helps to prevent tooth decay and gum damage in small children. Many municipalities add fluoride to tap water to increase this benefit. When children are given bottled water exclusively, they may miss out on these benefits and experience an increase in tooth decay and gum disease. Because some bottled water manufacturers use tap water as their base product, some bottled waters contain fluoride while others don't. The Centers for Disease Control recommend fluoridated water for good oral health.

Plastic Toxicity

Food-safe plastic containers can contain a chemical called bisphenol A, or BPA. BPA is an endocrine disruptor, meaning in interferes with your normal hormone function and especially disrupts estrogen. BPA leeches from its plastic source and enters food and water. Plastic drinking water bottles and many reusable drinking water containers contain BPA, according to Mother Earth News. Scientists are currently debating whether the amount of BPA exposure we receive from plastic food containers is safe or unsafe. Until the outcome of further testing is revealed, look for bottles that say "BPA Free" on the label to minimize exposure, or drink tap water.