Hey Costa Mesa, what’s that smell?

If you live in northern Costa Mesa and you thought you smelled something in the past few weeks, you were right.

From mid-September through this past Friday, the Orange County Sanitation District conducted its annual assessment of sewage lines in Costa Mesa — a process, officials said, that caused short-term odors in the northern end of the city but will help lead to long-term benefits.

The sanitation district assessed its pipeline that begins near Baker Street and the 55 Freeway and travels westbound toward the Santa Ana River before ending at the district’s treatment facility off Ellis Avenue, in Fountain Valley.

The project findings will create a baseline to optimize odor chemical injections into the system, which help reduce everyday odors and extend the useful life of the sewage collection system by reducing corrosion in the line, said sanitation district spokeswoman Jennifer Cabral.

The Costa Mesa Sanitary District issued a news flash about the process Monday, clarifying that the project was under county sanitation district jurisdiction, not its own.

Further questions can be directed to sanitation district staff at (714) 378-2965 or the 24-hour control center at (714) 593-7025.

The Costa Mesa project was part of a countywide effort.

—Bradley Zint

Twitter: @bradleyzint