Dogs are man’s best friend. . . as long as you clean up after them.

Never mind what stepping in dog excrement can do to your shoe — new research out from the professional chemists association American Chemical Society says dog poop can contain dangerous antibiotic-resistant bacteria, which can wash into our water supply and make man pretty sick.

All waterways are susceptible to contamination from animal fecal matter, writes study authors Orin Shanks and Hyatt Green, but Americans sure love dogs: There are nearly 70 million domesticated dogs in this country. Dog poop can contain antibiotic-resistant E. coli, among other parasites and bacteria, which, if left on the ground, can transfer into our water supply.

In order to determine how much of our water contamination comes from dogs, Shanks and Green developed a new genetic testing method identify waterways contaminated with dog waste. The method, which relies on doggy genetic markers, was successful in identifying contaminated rainwater.

But until a foolproof test can be developed and applied to our water, why don’t you just pick up after your dog?