When can babies drink water?

Under 6 months: no water

The American Academy of Pediatrics (AAP) is clear: babies under 6 months do not need water. Breast milk is approximately 87% water—it provides complete hydration alongside all the nutrients a newborn requires. Formula is similarly designed to meet all hydration needs.

Two specific risks make water dangerous for young infants:

Nutritional displacement: A young baby's stomach is small. Water takes up space that should be filled with breast milk or formula. If a baby drinks water, they are likely to take in less milk—reducing their calorie, fat, and protein intake at a stage when growth is rapid and nutrition is critical.

Water intoxication (hyponatremia): Infants' kidneys are not yet mature enough to process excess water. Too much water dilutes the sodium in their blood, potentially causing hyponatremia—abnormally low sodium levels—which can lead to seizures, brain damage, or, in extreme cases, death. This is why even well-meaning parents who dilute formula with extra water to stretch it further are putting their babies at risk.

When do babies start drinking water? The AAP recommends waiting until your baby begins eating solid foods, typically around 6 months, before introducing small amounts of water.

6 to 12 months: small amounts alongside solids

Water can be introduced as early as 6 months, ideally in an open cup or sippy cup. This helps infants develop cup-drinking skills and familiarity with water.

The important words here are: small amounts. At this stage, breast milk or formula should still be the primary source of nutrition and hydration. Water is supplementary, offered with meals to support digestion as solid foods are introduced, not as a primary drink.

How much water at 6–12 months: Most sources suggest 4–8 oz (120–240 ml) per day maximum at this stage, and on many days, less than that. The goal is familiarisation, not hydration replacement.

The primary reason to avoid large amounts of water for babies under 12 months is that it displaces nutrition. Up to a year, babies get a lot of their calories through liquid, either breast milk or formula. If your baby started drinking just water, it could easily displace some of their breast milk or formula intake.

12 months and older: water as a daily staple

At 12 months, you can start giving your baby whole or reduced-fat milk. Water also becomes a normal part of daily hydration from this point. By 12 months, kidneys are developed enough to handle regular water consumption, and the nutritional dependency on formula or breast milk as the primary fluid has shifted.

From 12 months, the question changes from "when can babies drink water?" to "what type of water should my baby drink?"—and that is where water quality matters.

What type of water is best for babies?

Can babies drink tap water?

For most US households, yes—from 6 months. Whether tap water is appropriate depends on your utility's specific contaminant levels, not on tap water as a category.

For babies under 12 months, boiling tap water is recommended only when a boil-water advisory is in place, your infant is premature or immunocompromised, or you are using well water. Boiling kills bacteria and some pathogens. However, it does not remove chemical contaminants like lead, PFAS, or fluoride—and it actually concentrates them, because as water evaporates, the same amount of contaminant is left in a smaller volume of water. For nitrates specifically, boiling is particularly dangerous: it concentrates nitrate levels further, increasing the risk of blue baby syndrome in infants under 6 months. If chemical contamination is a concern, filtering or using distilled water is the appropriate step, not boiling.

The contaminants that matter most for infants:

• ·Lead: No safe level of lead exposure exists for children. Lead affects neurological development. Infants are more vulnerable than adults because more of what they ingest is absorbed. If your utility or home plumbing has lead pipes or lead solder, a filter certified for lead removal is essential.
• ·Nitrates: Nitrate levels above 10 mg/L (the EPA MCL) can cause methemoglobinemia—"blue baby syndrome"—in infants under 6 months by interfering with oxygen transport in the blood. Nitrate is particularly common in well water and agricultural areas. Standard boiling does not remove nitrates and actually concentrates them.
• ·Fluoride: A small amount of fluoride in drinking water may support dental development, but too much causes dental fluorosis—white spots or streaking on forming teeth. The EPA MCL for fluoride is 4 mg/L; the recommended level for dental health is 0.7 mg/L. Infants who consume formula made with fluoridated water are at higher relative exposure.
• ·PFAS: PFAS are per- and polyfluoroalkyl substances—often called "forever chemicals"—linked to developmental effects in children. EPA MCLs for PFOA and PFOS are 4 ppt. There is no known safe exposure level for infants.

Can babies drink distilled water?

Yes—distilled water for babies is safe and is often recommended for formula preparation precisely because it contains no contaminants. Distillation removes essentially all dissolved solids, including lead, fluoride, nitrates, PFAS, and bacteria.

The trade-off: distilled water also removes all minerals, including calcium and magnesium. For formula-fed infants, this is generally not a concern because formula itself provides the minerals babies need. The water is a vehicle for delivering formula nutrients, not a nutritional source in itself.

One practical note: distilled water has a very low TDS (typically under 5 ppm) and a slightly acidic pH due to dissolved CO₂. Neither of these properties is harmful to a baby consuming formula—the formula's nutritional content far outweighs the mineral absence of the water itself.

For formula preparation specifically: Distilled water is one of the safest choices available, particularly in households where tap water quality is uncertain or where PFAS, lead, or nitrate contamination has been detected.

What about breastfed babies? If your baby is exclusively breastfed, distilled water as a separate drink is not necessary; breast milk provides complete hydration and distilled water adds nothing nutritionally. From 6 months, small sips of contaminant-free tap water or filtered tap water alongside solid foods are fine for a breastfed baby. Distilled water becomes more relevant when formula is involved, because the water is mixed into every feed, and any contaminants in that water are consumed in concentrated form multiple times a day.

Can babies drink purified water?

Yes—purified water is also safe. "Purified" is a broader category than distilled: it refers to water that has been processed to remove contaminants to below detectable levels, which can include reverse osmosis, distillation, deionisation, or combinations of these.

Purified vs distilled water for baby formula—the comparison:

For most formula-fed infants, the practical difference between distilled and high-quality purified (RO) water is small. Both are safe. Distilled water has slightly higher contaminant removal; RO-purified water may retain trace minerals. Neither requires remineralisation for formula preparation because the formula provides all necessary minerals.

Can babies drink fluoridated water?

For most infants, yes. In small amounts from 6 months, fluoridated tap water is considered safe. The recommended fluoride level in US community water supplies is 0.7 mg/L, set to support dental development while minimising the risk of dental fluorosis (white spots on forming teeth).

The nuance for infants: babies who consume formula made predominantly with fluoridated water are at higher relative fluoride exposure than breastfed babies or those drinking tap water in small amounts. The AAP has noted that formula-fed infants using fluoridated water may develop mild dental fluorosis on permanent teeth. For the full fluoride and formula discussion, see our baby formula water guide.

For babies drinking small amounts of uncontaminated tap water from 6 months alongside solids—a few sips a day—fluoridated tap water at 0.7 mg/L is not a concern. The exposure is too small to matter.

A 2024 National Toxicology Program (NTP) systematic review found moderate-confidence evidence linking fluoride exposures above 1.5 mg/L—which is more than double the US recommended level—to lower IQ in children. The review did not find sufficient evidence that 0.7 mg/L is harmful. The CDC, AAP, and ADA continued to support community water fluoridation following the NTP report. Check your utility's fluoride level in your ZIP report if this is a concern.

Can babies drink ionised alkaline water?

Not for formula preparation, but small amounts from 6 months for drinking alongside solids are generally considered safe with one important caveat.

For formula preparation: Ionised alkaline water (pH 8.5–9.5) should not be used to mix infant formula. Infant formula is precisely engineered to deliver nutrients at neutral pH. Alkaline water can alter the chemical balance of the formula and interfere with nutrient absorption. Water ionizers, such as Enagic® machines, have a neutral filtered water setting (pH 7.0, labelled "clean water") that is appropriate for formula preparation. The water passes through the FC1 carbon filter without ionisation. See our baby formula water guide for full details.

For drinking water from 6 months+: The research on alkaline water for infants is thin. There are no human RCTs on ionised water consumption in babies specifically. The general concern is that a baby's digestive system and kidney function are still maturing, and consistently alkaline water could theoretically affect the acid environment of the stomach. At the pH levels produced by ionizers (8.5–9.5), the effect on stomach acid is buffered quickly—the same argument applies to adults—but the precautionary position for infants under 12 months is to stick to neutral-pH water.

From 12 months, as kidney function matures and the diet diversifies, small amounts of mildly alkaline water (pH 8.0–8.5) alongside a normal diet are unlikely to cause harm. For toddlers, the clean water setting (pH 7.0) or the lowest ionisation setting is the more cautious approach rather than the full 9.5 drinking setting.

Can babies drink well water?

With caution. Private wells are not regulated by the EPA's Safe Drinking Water Act—unlike municipal tap water, there is no monitoring requirement, no utility testing, and no violation reporting. Well water quality depends entirely on local geology, agriculture, and the well's condition.

The specific risks for infants:

• ·Nitrates from agricultural runoff—the most common infant-specific well water risk
• ·Bacteria (coliform, E. coli)—not removed by boiling-only approaches in heavily contaminated wells
• ·Arsenic—common in certain geographic areas, particularly the Southwest and parts of the Northeast
• ·Lead—from well casing or pump materials in older installations

If you are on a well and preparing formula or giving water to a baby, annual well testing is recommended—and testing specifically for nitrates, coliform bacteria, lead, and arsenic. Standard home water test kits cover basic parameters; a certified lab test covers more.

What about gripe water?

Gripe water is an herbal supplement marketed to relieve colic, gas, and stomach discomfort in infants. It contains water as the primary ingredient, typically alongside ginger, fennel, or sodium bicarbonate, and often sweeteners.

Gripe water is considered an herbal remedy. Although many parents swear by it, the FDA has not approved gripe water—meaning no one is checking to make sure it's safe or effective. There is also no proof that it eases stomach discomfort in babies who may have colic.

The water quality in gripe water is worth noting: it is typically deionised or purified water, not tap water. In 2007, the FDA warned consumers about Baby's Bliss Gripe Water after confirming the presence of cryptosporidium—a parasite that causes intestinal infections—following the illness of a six-week-old infant who consumed the product.

Gripe water made in the US is a good way to ensure formulations do not contain alcohol and are more safely manufactured—but even US-made gripe water is not checked by the FDA.

The practical guidance: gripe water is not harmful to most babies in small amounts from reputable US manufacturers, but it has no well-supported evidence of effectiveness. If you use it, choose a US-made product without alcohol, sodium bicarbonate, or sucrose.

How much water should babies drink by age?

These are general guidelines. Individual needs vary with activity level, temperature, and solid food intake. The AAP recommends consulting your paediatrician with specific concerns about your baby's hydration.