They help you avoid BPA

The Japanese and Canadians have banned BPA, or bisphenol-A, entirely. Following their lead, the U.S. Food and Drug Administration (FDA) banned BPA from baby bottles and sippy cups in 2012. Why, then, do they still allow it in plastic water bottles? Studies show that BPA is harmful for your health. Stainless steel bottles that contain no plastics are 100 percent BPA-free.

They don’t contain other harmful chemicals

Despite the fact that studies show a clear link between BPA and reproductive issues, BPA is still ubiquitous in many plastic bottles, including both disposable and reusable water bottles. However, did you know that even if a plastic bottle does not contain BPA, it still likely contains other toxins? If they’ve been sitting around for a while or exposed to heat, almost all plastic bottles leak other endocrine-disrupting chemicals. Yuck!

In a 2011 study, researchers bought more than 450 plastic items that are designed to carry food and water from stores including Whole Foods and Walmart. They found that although most of the products were BPA-free, 70 percent of them released chemicals that acted like estrogen. And because plastic is porous, with each sip, you are likely getting a gulp of harmful bacteria along with it.

Stainless steel water bottles keep mold and other bacteria at bay

In addition to being chemical-free, stainless steel water bottles are rust, corrosion and stain resistant. If designed well, they don’t give mold and bacteria a place to hide.