In The U.S., Private Well Water More Likely To Have High Levels Of Heavy Metals

A recent pilot study conducted on nearly 200 pet dogs living in households that rely on private well water as their primary source of drinking water has raised concerns about the presence of high levels of lead, arsenic, and copper in the water. The study, led by Audrey Ruple, a Metcalf professor of veterinary medical informatics at Virginia Tech, found that at least two-thirds of the dogs tested were consuming water contaminated with these heavy metals.

The researchers highlighted the importance of monitoring the quality and safety of well water, as approximately 15 million households in the United States depend on private wells for their water supply. Previous research has shown that private well water often contains elevated levels of contaminants such as lead, arsenic, radon, and other pollutants that exceed the Environmental Protection Agency’s permissible limits for heavy metals. This poses a significant health risk not only to animals but also to humans living in the same households.

The study analyzed drinking water samples from 178 dogs residing in 10 different states, including California, Florida, Michigan, North Carolina, New York, Pennsylvania, Texas, Virginia, Washington, and Wisconsin. Despite 87% of the dog owners reporting that their pets were in good health, 82% admitted that their dogs were experiencing health issues that were not genetic or hereditary. The researchers discovered that a significant number of water samples contained high levels of lead, arsenic, and copper, indicating potential contamination in the well water supply.

Interestingly, only 16% of the dog owners were aware of possible sources of contamination near their wells, such as septic drain fields, oil storage tanks, ponds, or streams. This lack of awareness underscores the need for increased monitoring and testing of private well water to ensure the safety of both pets and humans.

The researchers concluded that testing dogs’ drinking water is an effective method for detecting harmful contaminants in well water. By sampling water from dogs living in households served by private wells, researchers were able to gather valuable data on geographic variations in water quality and sources of contamination. The study, published in the journal PLoS Water in August 2025, highlights the importance of regular monitoring and testing of private well water to protect the health of both animals and humans.