Skip Navigation

Why Is There an Outside Sewage Smell?


Ever wonder why the streets smell bad at certain times? It could be any of these reasons.

You might have gone to town or walked outside your home and noticed an unsavory smell. You are affronted with a plume of sulfuric fumes somewhere in your vicinity. Why is there an outside sewage smell? It is clearly the nearby sewer system. Why here and why now? Many ask these questions, and below, you shall find the answer.

What Is Sewer Gas?

The nasty odor you smell is sewer gas, a combination of gaseous chemicals that emerge when organic material breaks down. The organic material could be your average waste, but it could also be debris that does not belong in a sewer, whether for stormwater or wastewater. The concoction is hydrogen sulfide, a combination of methane, carbon dioxide, ammonia, nitrogen, and more. Together, they create the rotten egg smell.

Why Is There an Outside Sewage Smell?


Blockages could form rapidly or over a long time. Any buildup of organic materials could produce more odors, especially if other factors are at play. The gas will then seep through the catch basins of combined sewer systems and manhole covers up to the street above and into the surrounding area. 

Lengthy Travel of Materials

The longer the material remains in its original state without processing, the smellier it will get as it breaks down over time. That is why blockages will produce a stronger smell, as well as products that travel many miles to pass through certain areas prone to sewer smells. 


Many sewer systems rely on gravity to carry wastewater down to the treatment plant; they are designed to carry a general amount of water at a certain velocity. When more water than usual flows through the system, one can expect turbulence. Some parts of the system naturally have more turbulence than others, also. With this phenomenon comes stronger smells.

Hot Weather

Higher temperatures create more smells. If the sewage pipes are close enough to the surface or part of a combination sewer system, you are more likely to get a whiff of that nasty gas on a hot summer day. 

How to Treat That Outdoor Sewage Smell

Sewer system workers treat particularly smelly areas with a deodorizing chemical treatment at strategic times. Meanwhile, periodic sewer pipe cleaning keeps blockages at bay. Jet Blast Inc. is happy to help keep your municipality’s streets odor-free with water blasting and vacuuming services!

Contact Jet Blast Inc. Today!

Jet Blast® Industrial Services strives every day in an effort to provide our customers with the best service and equipment possible. Providing a safe and stable workplace has allowed us to keep a team of quality people with most having a tenure of 15 – 25 years with Jet Blast®. With all that experience under one roof, we have been able to provide reliable 24-hour service since 1979. I believe this helps to set us apart from the competition.

Compare us! Let us make your job easier. If you’re located in Maryland, Pennsylvania, Delaware, Northern Virginia, or Washington, D.C., contact us by email at [email protected], call us at 410-636-0730, or fax us at 410-789-3907, and don’t forget to keep in touch with us on Facebook!

This entry was posted on Friday, March 3rd, 2023 at 12:49 pm. Both comments and pings are currently closed.