STATE OF OUR SEAS

Are You Swimming in Sewage?

After a heavy rain, outdated combined sewer systems routinely pump sewage, trash and other waste into coastal waters, lakes and streams.

Spills from bursting, leaky sewage pipes make news headlines. But in many older areas, particularly in the Northeast and the Great Lakes, the problem of spilled sewage is chronic yet rarely reported. After a heavy rain, overburdened, outdated sewer systems routinely push sewage -- together with trash, motor oil and industrial waste that flows off of paved urban landscapes -- into the nearest water body.

Many older cities use a single sewer system -- called a combined sewer -- to carry both raw sewage from homes and offices as well as rainfall and snowmelt from streets. Some of the systems are 200 years old and were designed to accommodate communities with far fewer people living in a far less built-up environment. Today, as we pave over the land that normally soaks up and filters rainfall, even a quarter inch of rain can overburden the systems. The U.S. Environmental Protection Agency estimates that combined sewer systems overflow 43,000 times per year, discharging 850 billion gallons of raw sewage into our waters.

When untreated or partially treated sewage gets into the ocean, the bacteria in it can make swimmers and surfers sick. It also affects marine life. In the Florida Keys, for example, elkhorn coral is being decimated by white pox disease, which is caused by bacteria normally found in the human gut. Sewage in the water could also be feeding red tides and other blooms of toxic algae, which can shut down beaches, contaminate shellfish and possibly sicken sea turtles, whales and dolphins.

Some cities are using creative green strategies to ease the burden on their aging sewer systems. Rooftop gardens, street planters and more absorbent pavement can soak up rainfall before it gets into the system and forces sewage out.