For most people, filtered tap water is the best everyday choice. It delivers beneficial minerals like calcium and magnesium, costs almost nothing, and avoids the plastic waste of bottled options. But the real answer depends on what’s in your local water supply, how your home is plumbed, and whether you have specific health needs. Here’s what actually matters when choosing your water.
Why Minerals in Water Matter
Water isn’t just hydration. It’s a meaningful source of calcium and magnesium, two minerals tied to bone strength and cardiovascular health. Epidemiological research from the U.S., Europe, and Russia suggests health benefits kick in at around 20 to 30 mg/L of calcium and 10 mg/L of magnesium. Most U.S. municipal water systems already meet those thresholds, which means your tap water is quietly contributing to your mineral intake every time you drink a glass.
This is why ultra-purified water isn’t necessarily better. Reverse osmosis systems strip out calcium, magnesium, sodium, potassium, and zinc along with contaminants. Distilled water goes even further, removing virtually everything. Studies have linked long-term consumption of water low in calcium and magnesium to tiredness, muscle cramps, weakness, and even heart disease. If you rely on reverse osmosis or distilled water at home, a remineralization filter or getting those minerals from food becomes more important.
Tap Water: What’s Good and What to Watch
Municipal tap water in the U.S. is regulated by the EPA and tested regularly. For the vast majority of people, it’s safe and mineral-rich straight from the faucet. But two categories of contaminants deserve your attention.
The first is lead. The EPA’s safety goal for lead in drinking water is zero, because no level of exposure is considered safe. Lead enters water not at the treatment plant but inside your home or in the service line connecting your house to the water main. The most common sources are lead pipes, brass faucets, chrome-plated fixtures, and old lead solder on copper pipes. Homes built before 1986 carry the highest risk. If you’re unsure, running cold water for 30 seconds to two minutes before drinking (to flush standing water from the pipes) reduces exposure, and a certified lead-reducing filter eliminates it.
The second is PFAS, a group of industrial chemicals sometimes called “forever chemicals.” In 2024, the EPA finalized the first-ever national limits for PFAS in drinking water, setting maximum levels of 4 parts per trillion for PFOA and PFOS, the two most studied compounds. Five additional PFAS chemicals are now regulated at 10 parts per trillion or through a combined hazard index. Water utilities have several years to comply, so checking your local water quality report (available online from your utility) tells you where things stand right now. Activated carbon and reverse osmosis filters both reduce PFAS effectively at the household level.
Bottled Water vs. Tap Water
Many people assume bottled water is cleaner. The microplastic data tells a different story. A comprehensive UK study analyzing 177 tap water samples and 85 bottled water samples found microplastics in every single sample, regardless of source. Tap water averaged 40 microplastic particles per liter. Bottled water averaged 37 particles per liter. The difference was statistically meaningless.
Bottled water is regulated by the FDA rather than the EPA, and standards are broadly comparable. But bottled water isn’t tested as frequently, and you can’t look up a quality report the way you can for municipal water. You’re also paying roughly 1,000 times more per gallon for what is often just filtered municipal water repackaged in plastic. If you prefer bottled water for taste or convenience, it’s fine, but it doesn’t offer a safety advantage over well-maintained tap water with a good filter.
Mineral Water vs. Spring Water
These two terms have specific legal definitions. The FDA requires mineral water to come from an underground source and contain at least 250 parts per million of total dissolved solids, all naturally occurring. No minerals can be added after the fact. Spring water must come from an underground formation where water flows naturally to the surface, but it has no minimum mineral requirement.
In practice, this means mineral water consistently delivers higher levels of calcium, magnesium, and other trace elements. Some European mineral waters contain over 300 mg/L of calcium per liter, which is a significant dietary contribution. Spring water varies widely. Some brands are mineral-rich, others are closer to plain filtered water. If you’re buying bottled water partly for mineral content, check the label rather than trusting the name.
What About Alkaline Water?
Alkaline water has a pH above 7, typically in the 8 to 9.5 range. Marketing claims often promise everything from better hydration to cancer prevention. The clinical evidence is thin. Some studies suggest alkaline water may help slow bone loss, though it’s unclear whether the effect comes from the pH itself or from the added calcium. Other research hints that alkaline water combined with a plant-based Mediterranean diet may ease acid reflux symptoms. Neither finding is strong enough to recommend alkaline water over regular water. Your body tightly regulates its own pH through your kidneys and lungs, and drinking slightly alkaline water doesn’t meaningfully shift that balance.
If you enjoy the taste, alkaline water won’t harm you. But paying a premium for it based on health claims isn’t supported by current evidence.
The Best Setup for Most Households
A simple, cost-effective approach covers the bases for most people. Start with your municipal tap water, which already contains beneficial minerals. Add a quality filter, either a pitcher-style carbon filter or an under-sink system, to reduce lead, chlorine taste, and common contaminants. If your area has known PFAS issues, a reverse osmosis system paired with a remineralization stage gives you the cleanest water without sacrificing mineral content.
If you have a private well, the calculus changes. Wells aren’t covered by EPA regulations, so testing is your responsibility. Annual testing for bacteria, nitrates, and pH is standard advice, with additional tests for lead, arsenic, and other local contaminants based on your region’s geology.
Water for Infant Formula
Parents preparing powdered or concentrated liquid formula should pay attention to fluoride levels. Tap water often contains added fluoride to prevent tooth decay, but prolonged exposure to high fluoride levels during infancy can cause fluorosis, which shows up as faint white lines or streaks on teeth. Using low-fluoride bottled water for some or all formula preparation reduces this risk. Well water used for formula should be tested for chemicals, bacteria, and minerals that could be harmful to infants.