Toxic well water will affect household pets first, new study finds
Protecting dogs helps protect people
Virginia Tech
image:
Research from efforts like the Dog Aging Project reveals that even a dog's water bowl can offer crucial clues about shared environmental exposures.
view moreCredit: Photo by Margie Christianson for Virginia Tech.
Dogs drink water wherever they happen to find it — a puddle, a pond, a toilet. But the stuff in their actual water bowls almost always comes from the same tap their owners use. When that water is contaminated, both dogs and humans may suffer.
The risk is especially high for the 15 million American households that rely on private wells, according to a new Virginia Tech study in the journal PLOS Water. In dog drinking water sampled from wells across the country, 64 percent contained excessive levels of at least one potentially toxic heavy metal, such as lead, iron, sulfur, or arsenic.
Whatever’s in the water is likely in your dog too.
That’s the conclusion reached by the transdisciplinary trio of faculty members who collaborated on the study:
- Audrey Ruple, the Metcalf Professor of Veterinary Informatics
- Marc Edwards, University Distinguished Professor and professor of civil and environmental engineering
- Leigh-Anne Krometis, professor of biological systems engineering and Turner Faculty Fellow
“Dogs have historically been sentinels for heavy metal contamination in prior drinking water crises,” said Edwards, who cited not only the Flint, Michigan, water crisis that he’s well known for investigating, but also instances in Vermont and Massachusetts when a dog’s illness presaged lead poisoning in the pet’s human owners.
Sharing the same environment as their owners makes dogs a kind of “canary in the coal mine.” Their smaller sizes and shorter lifespans mean environmental toxins often affect dogs before they affect humans.
What’s different, Ruple said, is “they’re not sacrificial sentinels. With our dogs, we care deeply about the way that the environment is impacting their life, their health, and their longevity. And we can do something about it.”
Private wells pose hidden risks
As a member of the executive leadership team of the longitudinal Dog Aging Project, a multi-institutional project, Ruple has access to over 50,000 dogs that registered to participate. For this study, she invited a small selection of dog owners with wells to mail in samples of the water their dogs drink.
Why focus on well water? Municipal water must be tested regularly and meet federal standards, but private wells fly under the regulatory radar. In Virginia, 40 percent of well owners have no water treatment system at all, according to recent research by Krometis. “It's a big unknown risk sitting in your house,” she said.
Because heavy metal contaminants are often tasteless, odorless, and invisible, homeowners may not know there’s something in the water — until their dog gets sick. “Dogs living in these homes may be our first warning signs of environmental exposures in underserved rural areas,” Ruple said.
Water treatment systems make a difference
By comparing the results of water testing with existing data on the dogs’ health conditions, researchers identified some indicators that heavy metals may already be making dogs sick.
For instance, dogs whose drinking water was treated only with a sediment filter were more likely to have a diagnosed health problem, while dogs drinking well water treated by reverse osmosis were the least likely to be in poor health.
Future research will need to validate that correlation, but it’s already clear that wells using some health-based treatment systems can reduce heavy metals.
Protecting dogs helps protect people
Researchers urged households with well water to test and treat it. The Virginia Household Water Quality Program sponsored by Virginia Cooperative Extension offers free water testing throughout Virginia. “Knowledge is power and peace of mind,” said Krometis.
Dog owners are often quick to act when their pets’ health is at risk. When researchers told some study participants that their pet’s water showed elevated levels of arsenic, they immediately acted to mitigate the risk by treating their water.
“We care what happens to our dogs,” Ruple said. “We try to fix the environment for them too, not just for us. It highlights the strength of the relationship that we have with them. And I'm not just saying this because I am a dog person.”
Journal
PLOS Water
Article Publication Date
6-Aug-2025
What’s in your pup’s bowl? Heavy metals, reveals 10-state survey
A survey of pets who drink well water reports higher-than-advised levels of arsenic, lead and copper.
PLOS
image:
Companion dogs act as important sentinels of human health and wellbeing in considering a variety of risks and exposures, including potential illness from contaminated drinking water.
view moreCredit: Sexton et al., 2025, PLOS Water, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)
Two-thirds of dogs tested in a recent survey consume higher-than-recommended levels of heavy metals in their drinking water, according to a study published August 6, 2025 in the open-access journal PLOS Water by Audrey Ruple from Virginia Tech, U.S., and colleagues. The survey, which focused on well water households in 10 states, uncovered 13 instances where arsenic, lead and copper tested above EPA-recommended levels.
Roughly 15 million U.S. households use private well water and are not protected by the EPA’s Safe Drinking Water Act, which regulates safety testing in drinking water. These households — and the canine companions inside — are at an increased risk for consuming heavy metals that leach into groundwater.
In this study, the researchers analyzed drinking water samples from 178 dogs in homes not served by municipal water sources. All dogs are part of the Dog Aging Project, a long-term study of canine health and aging. Samples ranged across 10 states and tested for 28 heavy metals, about half of which are regulated by the EPA. Owners mailed drinking water samples to the researchers and completed detailed surveys about their dogs’ health and the home’s drinking water supply.
Across all 178 samples obtained, the researchers found detectable levels of all 28 metals tested. Two-thirds of the samples tested included at least one heavy metal over the EPA’s maximum contaminant level (MCL) or health guidance levels. In 13 instances, arsenic, lead and copper tested above the EPA’s MCL guidance levels.
Correlations identified within the experiment include: nearby fracking sites are associated with more sodium and sulfur in the drinking water; railroad tracks are associated with increased levels of manganese; and dogs drinking from water treated with reverse osmosis or a sediment filter were less likely to have a non-chronic health condition.
The researchers emphasize that big-picture conclusions require further study, and expressed a desire to continue testing dogs’ drinking water composition juxtaposed to their long-term health. Ultimately, this information can help guide veterinary care decisions and improve the health of the dogs’ human companions.
The authors add: “Many households served by private wells are flying under the regulatory radar. Dogs living in these homes may be our first warning signs of environmental exposures in underserved rural areas.”
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In your coverage please use this URL to provide access to the freely available article in PLOS Water: https://plos.io/3ILgHyq
Citation: Sexton CL, O’Brien J, Lytle J, Rodgers S, Keyser A, Kauffman M, et al. (2025) Testing for heavy metals in drinking water collected from Dog Aging Project participants. PLOS Water 4(8): e0000296. https://doi.org/10.1371/journal.pwat.0000296
Author Countries: United States
Funding: This research is based on data collected by the Dog Aging Project, which is supported by U19 grant AG057377 from the National Institute on Aging (authors funded on this grant include: SR, AK, MK, MDD, and AR), a part of the National Institutes of Health. The publicly available data are housed on the Terra platform at the Broad Institute of MIT and Harvard. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Method of Research
Observational study
Subject of Research
Animals
Article Publication Date
6-Aug-2025
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