So, Paris has decided to polish up its notoriously filthy Seine River for the Olympics. Everybody into the pool, or more accurately, into the Seine, right? Mayor Anne Hidalgo has already taken the maiden voyage, testing out the waters before the official Opening Ceremony. We have to wonder though, did she take a shot of antibiotics with her morning espresso before that dip?

Here’s the harsh truth. The City of Paris and proud patrons Eau de Paris have been swimming in numbers, navigating E. coli and enterococci bacteria levels, all of which are as delightful as they sound. But, can the Olympic swimming events brave the Seine’s bacterial roulette?

For three long years, Paris poured resources into building a massive $1.5 billion 'filter,' the Austerlitz basin, with the sole purpose of containing untreated wastewater, that was originally destined for the river, after a rainstorm. But it's like trying to put a plaster on an open wound, it can't stop the inevitable leakage.

"Rain is the beach party pooper," says Kartik Cherabuddi, MD, FACP, an infectious disease specialist. Rain increases the bacterial washout, making a post-storm splash especially risky. Couple that with Paris's ancient sewer system that can contaminate without a moment’s notice, and you’ve got a recipe for some serious GI problems.

Yet Paris is not alone in its mission to swim against the tide for cleaner urban rivers. London, Berlin, and Copenhagen have dived in too. But just because these elite athletes are swimming in the Seine, doesn’t mean we all should channel our inner Michael Phelps next year.

Ultimately, it’s your swim, your risk. Just remember this: urban rivers are bacterial hubs, a perfect storm for fecal contamination. So, before you do your best Olympic dive, maybe just check the water quality - unless diarrhea and stomach cramps are your idea of fun.