Dangerous chemicals may be lurking in your drinking water—and new research shows that the filter you're using may not remove them. "Check your city's annual water report and choose filters that are certified for removing contaminants in your area," suggests Cheryl Luptowski, a home-safety expert for NSF International. The most common culprits:
High amounts in water can cause lung damage comparable to decades of smoking tobacco; exposure to even low to moderate amounts can impair lung function.
This material, used in water pipes, can cause a buildup of amyloid beta, a protein that appears to spark brain changes associated with Alzheimer's disease.
It kills bacteria, but water treated with this chemical can combine with organic matter, like decaying vegetation, to form trihalomethane—a carcinogen in high levels.
The metal can be picked up by water traveling through service lines (especially in homes built before 1950), potentially risking increased blood pressure and kidney problems.