Today, it'd be a horrible idea to go swimming (without a state-of-the-art protective suit) in New York City’s heavily polluted Newtown Creek or Gowanus Canal. But, one day, you might be able to. The city is upgrading its wastewater system to prevent raw sewage from overflowing into the waterways when it rains.

And yet, another problem remains: Homes and businesses also send raw sewage or chemicals directly into the water. We often assume that pipes in our homes and offices lead directly to sewage treatment plants. But in some cases, unbeknownst to us, private pipes dump sewage directly into public waterways.

"None of us can be 100 percent sure that we're not contributing to [the problem]," City Limits' Jarrett Murphy told WNYC, "because these pipes tend to be multiple decades old... and even when you see a pipe that's spewing something it shouldn't be, finding where it goes to is a real detective story."

At one point, the Environmental Protection Agency surveyed the Gowanus Canal and found 250 outfalls, but it was impossible for them to tell which were legal and which weren't. So, can the average New Yorker help?

"If you see something, say something," Murphy added. "If you notice a pipe, and it's not raining but something's coming out of it, whether it looks clean or not, call it in to the [Department of Environmental Protection]. That's the best thing you can do, to be an eyes -- and nose -- for the city's environmental watchdog."

Murphy spoke with WNYC's Richard Hake. You can read his full report here.