Metal water bottles are BPA-free, and do not leak other harsh chemicals into the water its holding. Most bottles are made out of copper-lined 18/8 stainless steel, meaning it won’t retain colors ...

In a blog post, water bottle company Hydro Cell says that while metal water bottles are mostly safe to use, they must be made of high-quality stainless steel, such as an 18/8 food grade or 304.

Metal. Most metal water bottles are made from stainless steel or aluminum. “Metal obviates any concerns we have, rightfully or wrongfully, about plastic,” Swartzberg said.

Making a reusable water bottle doesn’t produce many carbon emissions, but plastic creates fewer emissions than glass and metal, according to Marcial Vargas-González, the science and innovation ...