Thanksgiving in East County came with an unwelcome side dish this year: a stubborn, sewage-like stench that had some residents rethinking their holiday plans and cracking open windows instead of carving the turkey.
From unincorporated El Cajon to La Mesa and Lakeside, residents reported waking up to a foul odor that lingered in the air throughout the week. Neighbors said it seeped into living rooms and kitchens, describing the smell as rotten eggs or a busted septic tank. While residents sniffed the air and compared notes, city and county crews fanned out across the area trying to track down the culprit.
El Cajon officials said multiple odor reports have been received by the city, prompting workers to inspect sewer and stormwater lines and open manhole covers to check for blockages. The San Diego County Air Pollution Control District also sent staff into the field to assess the situation, according to FOX 5 San Diego. County public works told the city there were no pump-station repairs underway in the affected area, which helped narrow the search. Deputy City Manager Marisol Thorn said agencies are coordinating as they work to pin down the source.
Resident Richard Huerta, who told FOX 5 San Diego he has lived in unincorporated El Cajon for eight years, said the odor has lingered for more than two weeks and often peaks after sunset and into the early morning. He compared it to rotten eggs and a septic tank and said he ended up changing his Thanksgiving dinner plans because of it. “We’re trying to figure it out,” he told the station.
Neighbors Trade Notes Online As Smell Spreads
As the stench drifted across neighborhoods, residents rushed to local forums and social media to confirm they were not imagining it. Posters reported catching whiffs of the same smell from La Mesa to Lakeside, noting that in some apartments, the odor was strong enough to be noticed indoors.
A Reddit thread collected accounts from late last week that all described the same rotten-egg scent and tried to map out where it was most intense. Those online reports aligned with the complaints the city received, helping officials decide which streets and neighborhoods to prioritize for inspections.
Officials Eye Seasonal "Pond Flipping" As Possible Culprit
County staff pointed to a seasonal mixing event, sometimes called “pond flipping,” as one possible explanation. In that scenario, water at the bottom of a pond, lake, or reservoir loaded with decaying organic material is churned up to the surface. When that happens, sulfurous gases can escape into the air and carry well beyond the shoreline.
Scientific guidance on lake and reservoir turnover notes that this type of mixing can release hydrogen sulfide and other foul-smelling compounds from bottom sediments into the atmosphere, which would match the rotten-egg odor that residents described. A technical overview of how these processes work is outlined in the EPA’s Lake and Reservoir Management Guidance: EPA/NALMS.
City Urges Reports As Investigation Continues
El Cajon officials say the investigation is still active and are asking residents to keep reporting odor incidents to the city’s non-emergency line so crews can track when and where the smell is strongest. The city has said it will update the public as agencies tighten in on the source.
Residents are advised to contact emergency services or County Public Health if the odor is especially strong or if anyone experiences health symptoms at the same time. During previous regional odor episodes, the San Diego County Air Pollution Control District operated its AIRE program to get air purifiers into the homes of vulnerable residents. Details on how to apply for a unit are posted on the district’s program page: SDAPCD AIRE.
