As public skepticism about water quality increases in the United States, more and more people choose to bottle or water treated at home instead of drinking straight from the tap.
But is this really a safer option?
A new study looking at water quality in California’s San Francisco Bay Area suggests that it doesn’t.
Research, published in PLOS waterfound that tap water, home treated water, and bottled water in the area all contained trihalomethanes (THMs), cancer-causing compounds formed during water disinfection. This issue extends beyond the Bay Area to much of the state.
“We’ve looked at aesthetic pollutants versus health pollutants in our research, and a lot of things that people think of as pollutants in water are unrelated to health impacts,” Samantha Bear, senior research scientist at SimpleLab and lead author of the study, told Newsweek.
Despite these findings, consumption of bottled water in the US is increasing, from 27.8 gallons per person per year in 2010 to 45.2 gallons in 2020, according to the study. This surge is driven primarily by the public perception that stream water is dirty or unsafe, coupled with incidents like the Flint Water Crisis in April 2014.
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Home water treatment systems are also growing in popularity, with a $2.09 billion market. However, many consumers are unaware of the specific contaminants they are targeting, often prioritizing taste or appearance at significant economic and environmental costs.
The study found that while tap water had the highest toxicity potential among the three water sources tested, bottled and home-treated water still posed health risks.
THM, a compound identified in all types of water, has been linked to long-term health problems, including bladder and colon cancer, as well as reproductive problems and birth defects, according to Delaware Health and Social Services.
Although the THM levels detected did not exceed regulatory limits, they were higher than recommended health benchmarks.
“So if we say that this contamination exceeds the limit, we mean it exceeds the health benchmark, we mean the concentration if you drink it over a lifetime, we would expect there to be a potential health risk,” Jessica Goddard, chief science officer at SimpleLab, told Newsweek.
“It’s not like someone is going to drink one of these samples and get bladder cancer. We want to make that clear because, for the most part, these contaminants are at regulatory levels.”
The study used the Bay Area as a representative location, where residents have access to tap, home-treated and bottled water. The authors believe that although toxicity levels may vary in other regions, the findings will generally be similar.
So, what can be done to solve the problem?
“One thing that can be done is that you can treat the water at home instead of buying bottled water. If you manage the treatment that you give in your home with what is in your water, then we expect that the load of contaminants in your home will be treated. The tap water will be more cheap,” said Bear.
Goddard added, “Regulators can be stricter about the concentration of trihalomethane allowed in drinking water rather than shifting the burden to individuals, which of course has economic implications based on who can provide treatment.”
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Reference
Bear, SE, Waxenberg, T., Schroeder, CR, Goddard, JJ (2024). Bottled water, tap water and household treated tap water-insights into potential health risks and aesthetic issues in drinking water. PLOS water. https://doi.org/10.1371/journal.pwat.0000272
