Olympic excitement has a way of surfacing environmental issues, which in turn trigger earnest reassurances that they’ll surely be fixed long before the opening ceremony. Besides, in the eyes of the Western world, Rio is, well, Rio, baby! Co-pa, co-pa-cabana. Soccer and supermodels, not poop.

Surely not poop, right?

The AP lanced that bubble last year with two investigations based on independent water-quality testing. The first, published in July, found that in certain venues, Olympic athletes are “almost certain to come into contact with disease-causing viruses that in some tests measured up to 1.7 million times the level of what would be considered hazardous on a Southern California beach.” In December, a second round of tests showed that the Olympic waterways teem with viruses and bacteria even far from land.

Poop, there it is.

The competitors are taking note. Athletes who have fallen in say the water stinks. Coaches are advising sailors to keep their mouths closed or to wash their hands after they touch wet gear. In nearby Rodrigo de Freitas, where Olympic rowers will compete, athletes in test events poured bleach on their water bottles and rinsed with antibacterial mouthwash between events, according to the AP.

Kara Gordon / The Atlantic

Officials have already admitted they won’t meet their stated goal of treating 80 percent of the sewage that flows into the bay. It’s more like 65 percent, according to the most recent estimate. There have been murmurs about moving the sailing venues further into the open ocean, where the water might be cleaner, but some athletes said they’d rather stick with the water they’ve trained on. And less than five months out, it’s far too late to change the host city.

Of course, water quality is not the only problem threatening Brazil’s Olympics. A recent outbreak of the Zika virus has sewage beat as the crisis du jour. Even there, though, water pollution plays a role. Pools of standing water accumulate all around Rio’s favelas, or informal settlements, where sanitation systems are aging or inadequate. Public-health experts say standing water, burbling with bacteria and low in oxygen, is prime breeding grounds for mosquitos, the main vectors for the Zika virus.

After visiting Brazil in December and talking with activists, bureaucrats, and everyday people, it became clear to me that this problem won’t be entirely solved by summertime. Officials are still scrambling to implement emergency measures that will clean up the water venues ahead of the Games. If they make progress, the Olympic athletes may be spared stomach cramps and infections. But the people who really suffer from Rio’s shoddy infrastructure will benefit much less—if at all.

Ipanema

Weekends find Ipanema beach dotted with umbrellas and criss-crossed by vendors selling coconut water and fried cheese. In the distance, small, rounded islands rise up out of the surf. On a 95-degree December day, the crisp, gentle waters beckoned locals and tourists alike.