Dog waste as an overlooked driver of water pollution: A case study in community-based remediation

Background

The US dog population has increased by ∼70% since 1996 and ∼⅔ of American households currently own a dog. Dog ownership can encourage exercise and offer mental health advantages, but dog feces can contain pathogens and protozoa that pose a danger to human health. Risks increase in urban environments with highly concentrated dog populations. Despite the growing prevalence of this issue, dog waste is underrecognized as a driver of water quality impairment and few templates of sustainable, community-driven remediation are available.

Methods

Water samples were collected from nine open water and storm drain sites under wet and dry conditions during bathing seasons 2023-2024. A two-prong behavior and infrastructure campaign was designed and implemented with community partners in 2024. In 2025, resampling was performed at only three sites of highest E.coli concentrations.

Results

Contrary to the assumption that leaky sewage disposal systems were causing local E.coli contamination, sampling in 2023 identified that high bacterial levels were driven by canine waste. Across all sites, 85% of high E.coli samples collected in 2023 had moderate to high levels of canine waste. This value reduced to 17% in 2024, the last year when all the sites were sampled. While the active intervention ended in 2024, the community experienced no beach closures in 2024 or 2025, the last year of available data.

Conclusions

Dog waste is an emerging public health concern facing many urban and suburban communities. This study offers a case study in the identification of dog waste as a driver of water contamination and a successful pathway for community-engaged remediation. Pet dog populations are expected to continue growing and coastal waters will likely face increasing threat from dog waste contamination. DNA-based technologies like microbial source tracking, as well as targeted, community-based interventions, will become increasingly necessary to understand and protect local waters.

Key messages

• Dog waste contributes to water quality impairment and public health risks, particularly in urban and suburban environments.

• Microbial source tracking analysis and community-based partnerships can be used to mitigate nonpoint source pollution from dog waste.