Water, water, everywhere, but does bottled beat tap to drink? Sure, bottled H2O comes in a handy to-go container and may come from a remote spring. But in the United States municipal water is usually just as safe — and almost free. And depending on where you live, it could even contain beneficial fluoride.

So quench your thirst at the faucet, unless:

There has been an official warning not to. “If there’s a significant health threat, the local water authorities may issue a ‘boil-water advisory,’” says John Millett, a spokesperson for the Environmental Protection Agency, which oversees federal water health and safety standards. Discolored water from rusty pipes should run clear after a short time. Cloudy water? Let it sit and the air bubbles (if they’re causing the cloud) will disappear.

You have certain health issues. Water microbial levels in some areas may be harmful if you have any immune-system problems. “Try a filter if you know you have high blood pressure and are drinking soft water, which has more sodium,” says Lisa Dorfman, a spokesperson for the American Dietetic Association. Also keep in mind that the high levels of calcium and magnesium in hard water may cause trouble for those prone to kidney stones. Learn more about your water in your Consumer Confidence Report, which utility companies are required to send out each year by July 1.