The stuff is everywhere.We know we’re supposed to clean up after our best friends—but a lot of us don’t.

According to Take Part, scientists at the U.S. Environmental Protection Agency (EPA) have developed new DNA testing to determine how much doggie doo-doo is in our waterways—and what that means for our health.

Dog waste contains bacteria such as E. coli, Giardia and parasites. When we don’t pick it up, that bacteria can run off into drain systems for lakes, rivers and ocean, triggering waterborne disease such as stomach virus or diarrhea.

But how responsible are irresponsible dog owners for our oft-polluted waters?

“The extent of water fecal matter attributable to dogs is poorly understood, in part due to the lack of reliable technologies able to discriminate between dog and other sources of fecal pollution,” Cathy Milbourn, an EPA spokesperson, wrote in an email.

The study, she said, was done in the hopes of creating tools that could give scientists and watershed managers a way to identify dog fecal matter when present in bodies of water.

To test their methods, the scientists tested storm water samples from an urban rainwater garden often visited by domestic dogs.

The test identifies 12 genetic markers commonly found in most dog fecal bacteria samples—but not those found in human waste.

“Findings suggested that these new assays (tests) may be helpful for the identification and quantification of aquatic fecal contaminants originating from canines,” Milbourn wrote.

The results were published last month in the journal Environmental Science and Technology and is available for anyone—such as health departments, government officials or watershed managers.

But before we can point the finger at canines, Milbourn said there are a few caveats with the testing. Right now, the tests aren’t able to measure how much of the disease-causing agents could be affecting local waterways.

“It is important to note that the development and publication of these methods is just the first step in a series of research needed to characterize the extent of canine fecal pollution in waterways,” Milbourn wrote.