Sewer Odor

Odors usually remain inside the sewers, but when a pipe runs full and/or the underground elevation of the sewer changes enough to stir up the wastewater, odors can build up to the point where they escape to outside air through pick holes in maintenance hole covers, through vents and other very small openings in the pipeline and connection points.

LA Sanitation (LASAN) is committed to treating objectionable sewers odors and preventing those odors from entering nearby neighborhoods. The ultimate means for accomplishing this goal is the installation of permanent Air Treatment Facilities (ATF's) where they will be most effective.

If you notice a foul odor coming from public sewers, please call our 24-hour Customer Care Center at 1-800-773-2489 or fill out the Sewer Odor Form to report the location.

Air Scrubber


ATFs are designed to fit into the neighborhoods in which they are located, both in their function and appearance. Each location is different: the site features, space availability, and capacity requirements at each site will all play a role in determining the overall design concept for each facility.

The facilities use microorganisms that feed on sewer gases and produce a harmless byproduct. The microorganisms used to treat the air passing through the ATFs are safe and commonly found in nature. They consume hydrogen sulfide and convert it into a non-odorous acid that is discharged into the sewer. The air then passes through a carbon scrubber (similar to an aquarium filter) to further remove any residual odor remaining after the biological process at a location other than a wastewater treatment plant. No harsh chemicals are used.


The Sewer Odor Control Advisory Committee (OAC) was formed in October 2002 as part of a court order resulting from an odor-related lawsuit against the City of Los Angeles by the Santa Monica Baykeeper and the US EPA.