For most people, filtered tap water is the best everyday drinking water. It’s regulated, inexpensive, and when run through a simple carbon filter, rivals or beats bottled water in both safety and taste. But “best” depends on what you’re optimizing for: mineral content, purity, cost, or environmental impact. Here’s what actually matters across the main options.
Tap Water: The Practical Baseline
Municipal tap water in the United States is regulated under the EPA’s National Primary Drinking Water Regulations, which set legal limits for over 90 contaminants. Lead, for instance, triggers mandatory action if more than 10% of samples exceed 0.010 mg/L. Nitrate is capped at 10 mg/L because levels above that pose a serious risk to infants under six months. In 2024, the EPA also finalized the first-ever limits on PFAS, the persistent industrial chemicals sometimes called “forever chemicals,” setting maximum levels as low as 4 parts per trillion for the two most common types.
The catch is that these standards apply at the treatment plant, not at your faucet. Old pipes, especially in homes built before 1986, can leach lead into water after it leaves the municipal system. If you’re concerned, running cold water for 30 seconds before filling a glass helps flush sitting water from pipes. A pitcher filter with activated carbon or a faucet-mounted filter removes chlorine taste, lead, and many common contaminants for pennies per gallon.
Your local water utility publishes an annual Consumer Confidence Report listing exactly what’s in your tap water. It’s worth a five-minute read. If your levels are within limits and you use a basic filter, tap water is a perfectly good choice.
Mineral Water: A Surprising Source of Nutrients
Natural mineral water comes from underground sources and contains dissolved minerals, primarily calcium and magnesium, in varying concentrations depending on the geology. What makes it interesting is how well your body absorbs those minerals. According to research reviewed by the World Health Organization, calcium from mineral-rich water is absorbed just as well as calcium from milk. Magnesium absorption from water averages around 46%, and jumps to about 52% when the water is consumed with a meal.
This matters more than it might sound. Drinking half a liter of a high-calcium mineral water (around 172 mg of calcium per serving) was enough to reduce the hormonal signal that triggers bone breakdown. During exercise, consuming about a liter of calcium-rich water completely prevented the spike in bone loss that occurred in subjects drinking low-calcium water. For people who are lactose intolerant, vegan, or simply not getting enough calcium from food, mineral water is a genuinely useful and underappreciated source.
One practical advantage of getting minerals through water rather than supplements: dietary calcium appears to reduce the risk of kidney stones, while calcium supplements may slightly increase it, possibly because supplements deliver a large dose all at once rather than spread throughout the day. Magnesium from water and food also avoids the laxative effect that magnesium supplements are known for.
Purified and Reverse Osmosis Water
Purified water has been processed through distillation, reverse osmosis (RO), or similar methods to remove nearly everything: bacteria, heavy metals, chlorine, and dissolved minerals alike. The result is extremely clean water, but it comes with tradeoffs.
RO water tends to taste flat or slightly bitter because the minerals that give water its pleasant flavor have been stripped out. It’s also slightly acidic. Many RO systems now include a remineralization stage that adds calcium and magnesium back in, which restores a more neutral pH and a better taste. If you install an RO system at home, spending the extra money on a remineralization filter is worth it, both for flavor and to maintain a small but steady mineral intake from your drinking water.
Purified water is a strong choice if your local tap water has known contamination issues or if you simply want the highest level of filtration. Just be aware that you’ll need to get your calcium and magnesium elsewhere if the system doesn’t remineralize.
Bottled Water: Convenience With Caveats
Bottled water falls into specific categories defined by the FDA. Spring water must come from an underground source that flows naturally to the surface, collected either at the spring itself or through a borehole tapping the same formation. Purified bottled water is simply treated tap or well water that meets certain purity standards after processing. Neither category is inherently better than the other; the label tells you the source, not the quality.
The bigger concern with bottled water is plastic contamination. A 2024 study from Columbia University found that a single liter of bottled water contains an average of 240,000 detectable plastic fragments. That’s 10 to 100 times more than previous estimates, which only measured larger particles. About 90% of these fragments were nanoplastics, particles small enough to cross cell membranes and enter the bloodstream. The long-term health effects of nanoplastic exposure are still being studied, but reducing unnecessary exposure is a reasonable precaution.
If you buy bottled water occasionally for convenience, that’s fine. But relying on it as your primary water source means higher cost, significant plastic waste, and meaningful nanoplastic exposure compared to filtered tap water from a glass or stainless steel bottle.
Alkaline Water: Limited Evidence
Alkaline water, typically with a pH between 8 and 9.5, is marketed with claims about neutralizing body acid, boosting energy, and slowing aging. The reality is far more modest. Your body tightly regulates blood pH regardless of what you drink, and no amount of alkaline water changes that. The Mayo Clinic notes that some studies suggest alkaline water combined with a plant-based Mediterranean diet may help relieve acid reflux, but adds that there isn’t enough research to confirm it.
If you enjoy the taste, it won’t hurt you. But paying a premium for alkaline water over regular filtered water isn’t supported by strong evidence.
Sparkling Water Works Fine
Plain sparkling water, whether naturally carbonated mineral water or carbonated tap water, hydrates just as effectively as still water. The carbonation doesn’t leach calcium from bones, despite a persistent myth that likely stems from research on cola (which contains phosphoric acid, not just bubbles). If sparkling water helps you drink more throughout the day, it’s a good choice. Just avoid flavored versions with added sugar or citric acid, which can erode tooth enamel over time.
What Actually Helps You Stay Hydrated
Hydration research using a metric called the Beverage Hydration Index shows that beverages with some sodium and other solutes are retained slightly longer than plain water. In younger adults, drinks with higher sodium content scored up to 1.24 on the index compared to water’s baseline of 1.00. But these differences are small and only matter in specific situations like prolonged exercise or illness. For everyday hydration, the type of water matters far less than simply drinking enough of it.
Adding a pinch of salt and a squeeze of citrus to a glass of water mimics what electrolyte products do. If you’re exercising hard in heat or recovering from a stomach bug, that’s a useful trick. For normal daily life, any clean water you’ll actually drink consistently is the best water.
Choosing Water for Infants
Water used to prepare baby formula deserves extra attention. The American Academy of Pediatrics recommends primarily using safe fluoridated tap water, with occasional use of non-fluoridated bottled water. The water should be low in minerals and contaminants. If your tap water comes from a well or you’re unsure of its quality, boiling it for one minute and letting it cool before mixing formula is a standard precaution. Avoid using mineral water or alkaline water for formula, as the mineral concentrations can be too high for an infant’s developing kidneys.
The Bottom Line on What to Drink
Filtered tap water checks every box for most people: it’s safe, cheap, environmentally low-impact, and with a basic carbon filter, tastes clean. If you want a mineral boost, choose a calcium-rich mineral water and drink it with meals for maximum absorption. If your local water quality concerns you, a reverse osmosis system with remineralization gives you hospital-grade purity without sacrificing taste or minerals. Bottled water is fine in a pinch but comes with plastic contamination you can easily avoid at home.