Inspired by a friend’s question about the damage carbonated waters might do to teeth, which can be demineralized by acidic solutions, I did a Sunday-morning experiment to test the acidity (low pH) of various sources of water, including (from left to right): a mineral water (Perrier), two seltzer waters (LeCroix & Arrowhead), lemon water, and tap water.

Using pH strips, I determined that the Perrier was the only water that wasn’t acidic, having a pH between 7 (neutral) and 8 (slightly basic). Tap water and Arrowhead were slightly acidic having a pH between 6 and 7. The LeCroix was more acidic, having a pH around 4. And the winner for very acidic, with a pH around 3, was the lemon water. I’d hypothesized that the Perrier would be non-acidic because of the buffering of minerals and that was correct.
Bottom line: if you want to protect your teeth, be careful about drinking a lot of acidic drinks like lemon water and beverages like LeCroix. The safest bubbly beverage would be mineral water like Perrier.