Do NOT Let Your Kids Drink Unfiltered Tap Water – Here’s Why

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There are so many things to consider when trying to raise a kid in a safe environment. Clean drinking water, or rather tap water, is one of them.

There might be potentially harmful contaminants lurking behind the faucets in your home that you did not anticipate. In this post, we will discuss 10 of them. They are neither the most common, nor the most toxic, but they can have serious health effects nevertheless, especially in children.

10 Reasons to NOT Let Your Kids Drink Unfiltered Tap Water

Please note: Contaminants are sorted from A to Z.

Tap Water ContaminantPeople ServedPeople Served Over Health GuidelinePeople Served Over Legal LimitPossible Health EffectsEffective Filtration Method(s)
Aluminum67M619,000No limitHarm to the brain and nervous system; impairment of brain developmentCeramic water filter
Arsenic71M71M392,000Bladder, lung, skin, liver, kidney & prostate cancerReverse osmosis, distillation, oxidation/filtration, coagulation/filtration, specialized adsorptive filter media, anion exchange, activated alumina
Atrazine29M14M0Hormone disruption e.g. harming reproductive system, delaying puberty and damaging testes; changes in nervous system, brain and behavior; cancerActivated carbon filtration
Chromium 6250M232MNo limitStomach and intestinal cancer; harming liver and reproductive system; delaying skeletal developmentReverse osmosis, ion exchange
CopperVomiting, stomach cramps, diarrhea, nausea, weight loss, liver cirrhosis, kidney diseaseActivated carbon filtration, reverse osmosis, ion exchange
Fluoride212M48,259Dental fluorosis; harm to bones; bone cancer; effects on thyroid function and brain developmentReverse osmosis, activated alumina, distillation
LeadHarm to brain and nervous systemReverse osmosis, activated carbon, distillation
Manganese77M3.9MNo limitDamage to brain and nervous system causing behavioral and attention problems, and impairing memory and intellectual capacityReverse osmosis
Nitrate224M188M64,904Oxygen deprivation in infants; cancer (colorectal, ovarian, thyroid, kidney, bladder and possibly other); harm to fetal growth and child development; adverse reproductive effects; changes in thyroid functionReverse osmosis, distillation, ceramic water filter
Perchlorate8.3M924,000No limitHormone disruption lowering the production of thyroid hormones which affects the metabolism and physical and cognitive developmentReverse osmosis

*Estimates for the U.S. (from 2010-2015), people on private wells not included[1]

1. Aluminum

The first contaminant we want to discuss that is commonly found in tap water is aluminum. Aluminum may be classified as a non-carcinogen, but it can harm the human brain and nervous system. In children, excessive exposure can impair brain development.

Despite this, no national drinking water standard exists for the regulation of the metal. A health guideline defined by the California Office of Environmental Health Hazard Assessment (OEHHA) is set at 600 parts per billion (ppb). At this concentration, aluminum should not pose a significant health threat.

The main contributors to aluminum contamination of our water sources are metal refineries and mining operations. Small amounts are released at coal-fired power plants and incinerators.

How can you protect your family from aluminum in tap water? With the help of a ceramic water filter.

2. Arsenic

Arsenic is a human carcinogen and exposure increases the risk of bladder, lung and skin cancer. Research also suggests that the mineral causes liver, kidney and prostate cancers. Other health concerns for arsenic are harm to the skin, lungs, brain, nervous system, kidneys and other organs, and the promotion of cardiovascular disease.

According to the Environmental Working Group (EWG), the cancer-causing effects of arsenic are particularly severe during early childhood.

When you look at the above table, it becomes obvious that tap water contamination through arsenic has become a serious problem in our country. The EPA has set the legal limit to 10 ppb. However, a California health guideline allows a maximum of 4 parts per trillion (ppt).

The difference is that at 10 ppb, arsenic-contaminated water potentially causes up to 600 cases of cancer in 1 million people when consumed for a lifetime. At 4 ppt, this number is reduced to 1 cancer case in 1 million people.

Where does the arsenic originate from? It’s a naturally occurring mineral and leaches from rocks into groundwater. Other sources are industrial (including mining waste, metal production, burning of fossil fuels) and agricultural (e.g. contaminated soil and water in orchards and farm fields).


Effective treatment methods to remove arsenic from tap water are reverse osmosis purification, distillation, oxidation/filtration, coagulation/filtration, the use of specialized adsorptive filter media, anion exchange, and activated alumina (learn more here). Regular carbon filtration won’t suffice.

It is also important that you limit your dietary arsenic exposure. For example, arsenic naturally accumulates at relatively high levels in rice and thus can also contaminate rice-based processed foods. This is why you should not feed infants and children rice-based cereals, pasta or milk.

3. Atrazine

Atrazine is a hormone disrupter that likely harms the human reproductive systems, leading to an increased estrogen and prolactin production in females and changes in testosterone levels in males. Animal studies have shown that these hormonal changes can delay puberty, alter the development and function of the breast, and damage testes. The greatest risk of atrazine-induced health effects is during pregnancy and early childhood.

Other concerns are changes in the nervous system, changes in brain and behavior, and different types of cancer.

The federal legal limit for atrazine in tap water is 3 ppb. The California OEHHA has set a public health goal of 0.15 ppb.

How does atrazine end up in our water systems? It is one of the most intensely used herbicides in the U.S. and enters supplies as agricultural runoff. What’s even worse: Suppliers are permitted to average atrazine measurements in water samples they collect throughout the year. In other words, the reported numbers underestimate atrazine peaks in spring/summer when the pesticide is applied in large amounts on farm fields.

The good news is that filtering atrazine from water is child’s play. All that’s needed is a high quality carbon filter.

4. Chromium 6

Chromium 6 a.k.a. hexavalent chromium is chromium in its sixth oxidation stage. It has been linked to causing cancer (stomach and intestinal), harming liver and reproductive system, and delaying skeletal development. Infants and children are at greater risk from chromium 6 exposure than adults.

On a side note: Chromium 6 was found in water served to 250 million Americans between the years 2010 and 2015.

That said, there currently is no national drinking water standard for the chemical, believe it or not. There is only a 100 ppb limit for total chromium. This combines chromium 6 and harmless chromium 3. Needless to say that this standard is completely outdated.

The OEHHA’s health goal is 0.02 ppb for just chromium 6. This threshold is considered to cause no more than 1 case of cancer in 1 million people who drink water contaminated with chromium 6 their entire life.

Pollution sources: Industrial (e.g. coolant at electrical power plants), but also natural occurrences in some areas.

What’s needed to get rid of chromium 6 in tap water is an ion exchange water filter or a reverse osmosis system. Want more info? Follow this link:

5. Copper

This one might surprise you but ingesting too much copper can cause vomiting, stomach cramps, diarrhea and nausea. Infants below the age of 1 are particularly susceptible. This is because their bodies have yet to develop the ability to regulate copper. Long-term exposure may also result in weight loss, liver cirrhosis and kidney disease.

As required per federal law, a water supplier has to get active whenever measured copper concentrations exceed 1.3 parts per million (ppm) in more than 10% of water samples collected in customers’ homes. However, this might not be enough to protect infants from copper toxicity which is why the Golden State has set the public health goal at .3 ppm.

By the way, most copper in tap water is leached from copper pipes in residential plumbing. High acidity and elevated levels of aluminum or chlorine can accelerate the corrosive effect.

copper piping

What you can do to protect your family is flush pipes for several seconds before using the water. And you should not consume water that has been sitting in pipes for long hours or overnight. Because the longer the water stays in the pipes, the more copper it will dissolve (especially when they are new) – of course this only makes sense if you have copper pipes in your home.

You also shouldn’t use warm or hot water for cooking as it dissolves more copper. The same goes for preparing infant formula. In fact, nothing but filtered water is recommended here.

Copper can be removed from tap water using reverse osmosis, activated carbon or ion exchange.

6. Fluoride

Fluoride is intentionally added to the majority of water systems in the United States in order to reduce dental cavities in citizens. However, there are health concerns regarding long-term fluoride ingestion through drinking water: Dental fluorosis, harm to bones and bone cancer. What’s more, the National Toxicology Program is looking into negative effects on thyroid function and brain development in children.

The EPA has established a legal limit for fluoride in tap water at 4 ppm, although much lower amounts can already be too much fluoride for infants. The EWG recommends caregivers to mix baby formula with fluoride-free water.

4 treatment methods are suited for fluoride removal from water:

  • Reverse osmosis
  • Activated alumina
  • Distillation
  • Strong base anion exchange (not for home use)

To learn more, check our fluoride removal guide on this page.

7. Lead

Lead is a neurotoxin that can affect the behavior and intellectual development in young children, and also impair their ability to concentrate. To make matters worse, these effects are permanent. The danger is highest during the first six years of life. This is because children’s brains are developing rapidly at that time and the blood-brain barrier isn’t yet formed.

Similar to copper, water utilities have to act when lead is detected at levels above 15 ppb in more than 10 percent of household water samples. Mind you, this action level is not a protective legal limit as in safe exposure level for children; it is based on mere practicability. Scientists agree that the ideal concentration of lead in drinking water is effectively zero. The OEHHA has defined their goal at 0.2 ppb.

If you wonder where the lead in our tap water comes from, old pipes and solder are the culprits. Before the 1930s, lead water pipes were used to build our water infrastructure. It is estimated that roughly 20 million Americans receive their water from a system that still uses lead pipes today. Lead pipes and solder can also be found in homes built before 1930. Actually, solder containing lead was used until 1986.

Apart from filtration – reverse osmosis, activated carbon and distillation all work – you should flush your water system before using any water for drinking and cooking if it has been sitting in the pipes for longer. Furthermore, only use cold water for cooking and, as always, don’t use unfiltered tap water when mixing baby formula.

8. Manganese

Manganese exposure beyond a certain threshold can damage the brain and nervous system in infants as well as kids. This in turn can cause behavioral and attention problems, and impair memory and intellectual capacity.

And yet still, the EPA has not set a national legal limit for manganese in tap water up to this point. There is only a non-enforceable guideline of 50 ppb, but this is more about aesthetics since water can start to taste bad above that level.

The EWG considers 50 ppb of manganese in water for bottle-fed infants safe. The same could be true for young children, research suggests.

Manganese in our tap water, how did this happen? It’s a naturally occurring element, so it’s nobody’s fault.

A reverse osmosis system can help you eliminate it. Yes, there are other filter methods but RO is best for drinking purposes.

9. Nitrate

Health risks associated with excessive nitrate exposure include:

  • Oxygen deprivation in infants (methemoglobinemia)
  • Cancer (colorectal, ovarian, thyroid, kidney, bladder and possibly other)
  • Harm to fetal growth and child development
  • Adverse reproductive effects
  • Changes in thyroid function

The current legal limit for nitrate in public drinking water is 10 parts per million. The standard was established to protect infants from methemoglobinemia, or blue baby syndrome, in which an infant suffers from oxygen deprivation in the blood. The standard does not address long-term, low-level nitrate exposure in drinking water, though.

The EWG health guideline of 0.14 ppm corresponds to a one-in-a-million cancer risk.

One of the uses of nitrate is as a fertilizer. This is how it ends up in our water systems – as agricultural runoff. Water in areas with intense agriculture usually has the highest nitrate concentrations. Nitrate in manure is another reason for this.

nitrate in manure

Urban areas may detect elevated nitrate levels in their water due to discharges from municipal wastewater treatment plants and septic tanks.

The most effective way to have nitrate removed from your water? Reverse osmosis, distillation and using ceramic filter media. It is also important to cut back on red and processed meats.

10. Perchlorate

Fortunately, perchlorate in tap water is relatively rare. It was detected in water served to 8.3 million U.S. residents in 2015. “Only” 924,000 of them received water containing perchlorate at concentrations above the health guideline.

What makes perchlorate dangerous? It’s a hormone disrupter. Blocking the thyroid’s ability to take in iodine, it can lower the production of thyroid hormones affecting metabolism and physical and cognitive development. Infants and fetuses are most at risk.

At this point, it probably does not come as a surprise to you that perchlorate in tap water is completely unregulated, at least on a national level.

Why is that? Rumors say our Department of Defense, military contractors and the aerospace industry have lobbied against regulation. After all, they use and release 90% of all domestically produced perchlorate. This is also why contamination around defense contracting sites and military operations can be high. To be fair, the chemical also occurs naturally.

In case there’s perchlorate in your tap water you can apply reverse osmosis purification and not have to worry about it anymore.


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About the Author Gene Fitzgerald

Gene Fitzgerald has been with BOS since the very beginning. She is head of content creation and has fully immersed herself into the home water treatment industry only to become an expert herself. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
Learn more about Gene and the rest of the BOS Team.


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