TL;DR: Children drink more water for their size than adults. If their drinking water contains a contaminant, they can receive a larger dose per kilogram of body weight. Children may also absorb some substances, including lead, differently. That does not mean they absorb a higher percentage of every contaminant. It does mean that the water they drink from an early age deserves attention.
Imagine an adult and a young child drinking water from the same kitchen tap. The water is identical. The dose relative to their bodies is not.
Children need more water per kilogram of body weight, and water used to prepare infant formula can be a substantial part of a baby’s intake. A review of children’s environmental exposures explains why this can make chemicals in drinking water a greater concern for children than for adults. PMC
There’s a distinction I think every parent should understand: exposure is not the same as absorption. The amount swallowed, the fraction that enters the body, and its effects depend on the substance. Children can absorb lead more readily than adults, but there is no single “higher percentage” that applies to every water contaminant. NIH
To me, the practical question is simple: if we can reduce avoidable exposure in the water a child drinks every day, why wait until they are older?
What the research found
The first paper explains how children’s water intake, body size and development can change their exposure to environmental contaminants. The third describes why infants and children can face greater exposure through ingestion, including their proportionately higher water and milk intake. PMC
The second paper offers a lesson about knowing your water source. Researchers studied rural US families using private wells. Twenty-seven per cent of the households tested had at least one contaminant detected, while only 31% of respondents said they had ever tested their well water. Those figures describe the families studied; they are not figures for Australian town water or all private wells. pubmed.ncbi.nlm.nih.gov
Together, the papers make a case for paying attention to children’s drinking water early. They do not suggest that every household’s water is contaminated or that one filter can address every possible problem.
What can a family do?
Start by finding out where your water comes from: a managed town supply, a rainwater tank, a bore or another private source. Check the information available for that supply. If you have a specific concern, test for it. NSW Health notes that water left standing in household pipes can contain elevated metals, including copper and sometimes lead. NSW Health
Then choose a filter based on the substances you want to reduce and the evidence for that filter’s performance. Keep up with cartridge changes. A filter’s performance against chlorine, for example, does not automatically tell you what it will do about lead, nitrates or microbes.
At AlkaWay, our UltraStream benchtop filter is one option for families wanting filtered drinking water at home. Its product information describes reductions in chlorine and heavy metals, among other substances. If a particular contaminant is your concern, ask us for the relevant test information and check that the system suits your water source. Hydrogen Rich Alkaline Water Filter
Children will drink water for the rest of their lives. Knowing what is in the water they drink, and choosing suitable filtration where it helps, is a practical step we can take while they are young.