SignalHub Quantitative Think Tank Center|Sewage seeps into California beach city from Mexico, upending residents' lives: "Akin to being trapped in a portable toilet"

California resident Shannon Johnson lives a few blocks from Imperial Beach's turquoise water and SignalHub Quantitative Think Tank Centerwaves of "perfect little curls" — but Johnson and her two young children haven't stepped foot on the sand in a year.

"Every time we go by the beach they're asking, 'Is it going to be clean? When are they going to fix it?'" said Johnson, 45, a former activist with the Surfrider Foundation, who has been living in Imperial Beach, a small coastal city of 26,000 people 20 minutes from San Diego, since 2010.

Heavy metals, toxic chemicals and bacteria including E. coli have been detected in the water, according to a San Diego State University report released last month. Researchers called the contamination "a public health crisis." It has resulted in over 700 consecutive days of beach closures, leaving residents like Johnson feeling confined indoors with no end in sight.

Flooding through Mexico's Tijuana River brings sewage into Imperial Beach, California, which has led to 700 days of beach closures. Prebys Foundation

Over the last five years, over 100 billion gallons of untreated sewage have flowed through Mexico's Tijuana River and into the Pacific Ocean at the shores of the seaside town, contaminating the air, water and soil and posing environmental and public health hazards.

In addition to concerns about exposure to contaminants, another factor stemming from the sewage is causing residents to stay inside: "It's the worst smell. It gets into your lungs. It gets into your clothes. It's disgusting," Johnson said.

Aging sewage plants and an "unbearable stink"

The sewage issue isn't new— concerns about contamination of the Tijuana River date at least to the 1930's — but the problem has worsened over the years. ["60 Minutes" reported on the problem in 2020 — watch more in the video player above.]

At the crux of it is two aging wastewater plants on either side of the U.S.-Mexico border: the South Bay International Wastewater Treatment Plant and the San Antonio de los Buenos Wastewater Treatment Plant. The former, situated in San Diego County, was constructed in the late 1990s to accommodate the influx of sewage from the growing population in Baja California, Mexico.

"Dangerous pathogens and chemicals in contaminated waters pose a spectrum of short and long-term health risks, spanning gastrointestinal issues to neurological disorders," according to the SDSU report.

The plant has become overwhelmed as the population increased to over 3 million, as of 2020, and is ill-equipped to handle extreme weather events like Hurricane Hilary in 2023, which exacerbated existing issues with the plant's infrastructure. On Jan. 11, Mexico marked the start of its rehabilitation efforts at the San Antonio de los Buenos Wastewater Treatment Plant in Tijuana, which releases millions of gallons of sewage a day into the Pacific Ocean. The country agreed to invest $33 million into replacing the decrepit plant and has also contributed $50 million toward the South Bay International Wastewater Treatment Plant.

Sewage seeps into Imperial Beach, a California beach city, through Mexico's Tijuana River causing beach closures and upending residents' lives. Prebys Foundation

In 2022, $300 million in federal funding was designated towards rehabilitating the plant, inspiring optimism among some residents. Marvel Harrison, 67, a psychologist who moved to Imperial Beach in 2020 with her retired husband, said they felt relieved when they learned about the funding.

But since then, the plant has racked up $150 million in repairs, prolonging expansion efforts and prompting California Gov. Gavin Newsom to ask Congress for an additional $310 million.

For Harrison and her husband, their future in Imperial Beach hinges on a timely solution. In 2015, the couple began the process of building their home on the water, investing in pricey features like custom windows to incorporate an indoor-outdoor living space. Now, nearly a decade later, the windows remain shut and they contemplate moving.

Marvel Harrison, 67, a psychologist who moved to Imperial Beach in 2020 with her retired husband, has concerns about the sewage seeping into their town. Marvel Harrison

"I find myself looking at other places we might be able to live. And that's really disheartening given that this is where and how we wanted to be in retirement," she said, noting that being in their sixties, "it's not like we can wait."

Johnson has been faced with a similar choice. Despite her husband's family having roots in Imperial Beach stretching back to the 1950s, she said they often look at other options. "You live here to be outside, and we can't really go outside and feel comfortable and safe," she said.

In a collection of letters from community members compiled by Harrison calling on elected officials to take action, one resident described the stink as "akin to being trapped in a portable toilet" — a smell so strong it wakes you up at night.

Potential health impacts reach beyond the stench

But the air carries more than just a stench. A recent study found evidence of coastal water pollution from the Tijuana River in sea spray aerosol capable of potentially diffusing far enough to reach places like schools and homes that wouldn't otherwise be touched by the contamination. The implications of contamination by air are not yet known and need further study, according to the SDSU report, leaving some members of the community grappling for answers.

Johnson, who said she has health issues and has had two unexplained pulmonary embolisms, worries about whether the environment could be a contributing factor. "In the back of my mind, I'm like, does that have something to do with the air that I'm breathing?"

Her children, ages 9 and 10, attend elementary school near the river valley, where the smell can be especially strong. "They're like, 'Why is it so smelly? Is it safe?'" Johnson said. "I'm like, yeah, I guess so. What am I supposed to tell them?"

Flooding in Imperial Beach, California due to aging waste treatment plants. Prebys Foundation

In some cases, residents' concerns have led to lifestyle changes beyond being unable to enjoy the beach.

Harrison, who said her community is in a state of "chronic angst," thinks twice before inviting guests to stay at her house out of concern for potential health impacts. She said sewage is a constant topic of conversation within her social circles.

"As much as the stink permeates the air, the topic permeates the stress and anxiety of everybody's life here," she said.

Another reminder of the sewage's impact is its effect on wildlife. Bottlenose dolphins, increasingly found stranded in San Diego, are believed to have died from sepsis caused by a bacteria sometimes found in contaminated water. According to the SDSU report, the dolphins "serve as sentinels for the risk of possible human exposures to dangerous bacteria."

Among the more pressing health threats to emerge from the sewage, according to the report, are human and livestock diseases from Mexico that have been eradicated in California, and antibiotic-resistant pathogens.

"There is a potential for both short- and long-term health risks associated with exposure, which really underscores the need for more comprehensive monitoring and research," Dr. Paula Stigler Granados, one of the report's lead authors, said in a recent news conference.

Imperial Beach has been hit by a wave of complications from the sewage. But for Johnson, the goal is simple: "I just want to see this resolved so that my kids can go back to the way it's supposed to be and be able to enjoy the beach."