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Story Publication logo December 7, 2021

As Raw Sewage Flows, Guaymas Residents Beg: “Please Listen to Us”


photo of Guyamas sewage

A city’s inadequate wastewater treatment system allows water with bacteria levels far exceeding...

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This project was produced in partnership with KJZZ's Fronteras Desk.

This story is the second of three in a series. In addition, listen to the project's two-part radio series by clicking here.

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GUAYMAS, Sonora — A few feet from the front porch of Claudia Fourcade’s childhood home, an exposed sewer pipe filled with green liquid exudes a putrid odor. Waste drips into a growing puddle in the middle of the road.

Fourcade, 24, holds a handwritten sign on an orange poster board, pleading in Spanish: “Please listen to us. We can’t take it anymore.” She and her neighbors have staged a small protest this late summer afternoon, constructing a roadblock of trash and debris to get the attention of water company workers.

The mother of two children, ages 5 and 7, Fourcade said the stench infiltrates her home, making it impossible to enjoy eating. She can’t even do laundry at home because the smell permeates her clothes.

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“It’s disgusting,” she said. “It’s really uncomfortable living like this.”

Once she tried to cover the broken pipe with concrete. But when the pressure of the waste became too great, it broke through again, she said.

Fourcade’s exposed sewer pipe exemplifies a common problem in Guaymas: poorly installed infrastructure.

The soil is rocky and hard to dig into, so many sewer pipes were installed too near the surface, said Marco Antonio Ahumada Gutierrez, former regional director for the Comisión Estatal del Agua, or CEA, in Guaymas, San Carlos, Empalme and the small Yaqui community of Vicam.

“It has no depth, because it’s pure rock,” said Ahumada, who has a degree in hydraulics and a master’s in business administration. He worked in various local directorial roles for the CEA between 1993 and 2015, plus five years as regional director between 2009 and 2014.

The pipes should be buried at a depth of 50 centimeters, over at least a 20-centimeter bed of sand to cushion them, he said. Instead, many pipes were installed on top of uneven rocks, and the pressure of overhead traffic quickly results in broken or collapsed pipes, Ahumada said.

Ahumada, a Guaymas native, was one of four former directors of the CEA who spoke with the Star about the root causes of Guaymas and San Carlos’ sewer crisis.

In separate interviews with the Star, the former CEA directors described the major challenges facing the under-resourced utility company: rocky soil and mountainous topography, plus major financial troubles.

While sewage problems are common throughout Sonora, Guaymas faces all those challenges at once, said former CEA regional director Ivan Cruz, whose term ended in September.

Across downtown Guaymas, a catastrophic summer of sewage crises culminated in the Sonoran state government declaring a health emergency in early November.

“There are other sewage issues in the state, but not like Guaymas,” Heriberto Aguilar, secretary for infrastructure and urban development in Sonora, said in Spanish. “Nothing should arrive at being an emergency. That means they failed.”

A couple doors down from Fourcade’s protest, Brenda Lopez is making flour tortillas by hand as her 6-year-old son, Jesus, plays with neighbors. He was recently sick for 12 days with diarrhea and vomiting, which she attributed to sewage exposure.

The odor from the open sewer pipe isn't helping her business, she said.

“Who would come buy tortillas in this stink?” she said. “We’ve complained a lot, and no one pays attention.”

Water company has 3-year plan

New state CEA director José Luis Jardines Moreno and regional director David Pintor — who oversees Guaymas, San Carlos, Empalme and Vicam — were appointed in September, after the local and state elections. Both declined a request for an interview.

In response to the Star and KJZZ’s questions, a governor’s office spokesman provided written responses that he said were compiled by various departments in the agency.

The agency said infrastructure failures necessitated the emergency declaration to protect the health of citizens.

Clogged pipes and broken sewage pumps “represent a risk to the health of the people who pass through the area and requires expedited attention to solve the problem,” the CEA statement said in Spanish. “In the next three years, it is planned to carry out major investments in drinking water, sewerage and sanitation in order to finally resolve this situation.”

Water shortages worsen problem

Water shortages have exacerbated the sewer problems in Guaymas and San Carlos, former CEA regional directors Roberto Romano and Ahumada said.

PVC sewer pipes are designed to carry a steady flow of pressurized water. But Guaymas and San Carlos residents have had a rationed water system, in which households receive the city’s potable water only a few days a week. (In some cases, water shortages or line breaks have resulted in much longer stretches without water, Romano said.)

In Guaymas and San Carlos, most homes have water storage tanks on their roofs, holding excess water for use on days when there’s no flow from the city.

The inconsistent water flow strains sewer pipes, which have to withstand intermittent dry spells, between periods of high-pressure water flow, said Romano, who was CEA regional director for 4½ years before leaving the position in 2019.

“They are not designed for that type of pressure,” he said. “They are designed for stable water conduction.”

Another issue is the aging aqueduct that brings Guaymas’ water from Obregon, 120 kilometers away. At 31 years old it is reaching the end of its useful life, Ahumada said.

Avenida Serdán, a major thoroughfare in downtown Guaymas, was flooded with sewage for much of the summer because of collapsed sewer pipes and broken sewage pumps. Near this intersection, street vendors sold food and drinks as pedestrians picked their way across the wet pavement on Sept. 10. In the background, CEA workers attempt to break up a clogged pipe using a thin rod called a varillo. Image by Emily Bregle. Mexico, 2021.

Broken pumps

Pipes aren’t the only problem. The city’s sewage pumps are poorly maintained, often vandalized or robbed for parts, and routinely break down, leading to sewage backups.

“If you go and look at one of the pumping stations, they look abandoned,” Romano said.

For much of last summer, only three of the city’s network of 11 sewage pumps were functioning, said Sebastian Orduño, who was elected to represent Guaymas, including San Carlos, in the state Congress this year.

“We reached a point where many areas of Guaymas, especially the main avenues, were flooded with sewage,” he said in a text message in Spanish. “People have had to learn to live with this problem, due to the indifference of past governments.”

Sewage problems exist throughout all of Sonora, said Sergio Avila, former state CEA director. He left his position in September, when the new governor was elected. But in other cities, the leaks tend to be less noticeable, he said.

“Guaymas has a problem,” he said in Spanish. “Anything that leaks can be seen by everyone because it all flows to a focal point in the city.”

Water samples taken by the Star on Sept. 13 found that the wastewater flowing on Avenida Serdán, a major Guaymas thoroughfare, had fecal coliform levels of 7.8 million parts per 100 milliliters, confirming it to be raw sewage. Fecal coliforms are the type of bacteria found in the intestines of warmblooded animals, and they’re often used as a proxy for fecal contamination in water.

Open-air food vendors operate downtown even as the streets are flooded with sewage, creating a massive health hazard, said Jaqueline García Hernández of Guaymas’ Center for Investigation in Nutrition and Development, or CIAD.

Even when the pools of sewage evaporate or drain away, contaminated dirt coats the streets and wafts through the air, impossible to escape, she said.


Like many Mexican cities, Guaymas doesn’t have a separate stormwater system; all water flows into the sewer system.

That means rainwater collects everything in its path — including sand and the bountiful piles of trash in the streets — and washes it into the already overloaded sewer system.

During the monsoon, perhaps well-intentioned residents sometimes open the manhole covers to allow more rainwater to drain from the streets, an open mouth for trash and debris.

This summer the level of trash in the streets was worse than usual, residents say. For months, the city’s contracted trash carrier, called PASA, didn’t collect the trash at all. As Guaymas residents put it, “PASA no pasa.”

Local media reported contract disputes and a COVID-19 outbreak at PASA as the culprits, leaving Guaymas residents not only flooded with sewage, but surrounded by mountains of garbage — which comes with its own health risks.

Any study on the health impacts of sewage in Guaymas would be confounded by the simultaneous health risk of rotting trash in the streets, said José Arreola, director for the Northwest Center for Biological Research in Guaymas.

“Garbage collection in the city is very deficient and represents a serious problem due to its adverse effects on public health, also including risks of gastrointestinal and respiratory diseases,” he said.

Contamination is widespread

Between August and November, the Star took water samples from Guaymas bays, arroyos and streets, as well as samples from the natural wastewater treatment system in San Carlos, called an oxidation lagoon. The lagoons are the sole wastewater treatment available in either San Carlos or Guaymas.

The water testing, conducted by CIAD lab in Guaymas, measured the presence of fecal coliforms.

Testing results revealed sewage contamination in a Guaymas bay in violation of federal environmental standards and confirmed that the wastewater flowing through downtown Guaymas was raw sewage.

The Star’s testing also revealed that the oxidation lagoon in San Carlos is not consistently effective in purifying the human waste that is pumped there.

Sunset over habor
San Carlos doesn’t have a modern wastewater treatment plant. It relies on a three-pond oxidation lagoon, which is supposed to clean wastewater through the natural interaction of sunlight, algae, oxygen and bacteria. Water-quality testing by the Star shows the lagoon’s effectiveness varies dramatically depending on the volume of waste flowing into it. Image by Guillermo Soberón Tirado. Mexico, 2021.

Oxidation lagoon a bare minimum

Development in San Carlos is escalating, without corresponding support for the aging sewer system, or any concrete plans for a modern wastewater treatment facility, local leaders say.

Like Guaymas, San Carlos’ wastewater treatment system is also solely dependent on an oxidation lagoon, managed by the CEA, with the exception of the homes that are on septic systems and some private businesses that have built their own oxidation lagoons on the outskirts of town. The Country Club also has its own single-pond oxidation lagoon.

The natural wastewater treatment method is supposed to use a combination of sunlight, oxygen and bacteria to clean wastewater.

But in the U.S., it’s used only as a secondary or tertiary treatment, after wastewater has already gone through a conventional water treatment plant, said David Walker, research scientist in the University of Arizona’s Department of Environmental Sciences.

While it’s better than nothing, “oxidation ponds were never meant to be a sole source of treatment anywhere. An oxidation pond is literally the least anybody can do,” Walker said. And in Mexico, “there’s not much teeth in the regulations to stop them from doing that.”

Many under-resourced Mexican towns and cities rely solely on oxidation lagoons, making do with inadequate wastewater treatment, said Alejandro Olivera, senior scientist and Mexico representative for the Tucson-based Center for Biological Diversity.

“It’s usual — but it’s not good,” said Olivera, who is based in La Paz, Baja California.

Even the oxidation lagoons that succeed at reducing levels of fecal contamination aren’t addressing other contaminants, like heavy metals and chemicals like nitrogen and phosphorus.

And even if a lagoon has a 90% or more rate of removal for fecal coliform bacteria, that figure sounds more impressive than it is, Walker said.

“If you’re starting at a huge (fecal-coliform) level, like what’s found in raw sewage, it’s really not difficult to show a high rate of removal efficiency,” he said. “This doesn’t mean the effluent is by any means safe, because that 10% residual (fecal-coliform level) could still be many fold higher than what would be considered safe to release into the environment.”

In San Carlos, the oxidation lagoon has three ponds. The first contains raw sewage, pumped from all corners of town. In the first pond, the solids and sediment sink to the bottom of the pond. Liquid flows to the second pond, where exposure to sunlight, oxygen and bacteria eats away at the dangerous pathogens in the waste.

By the third pond, the water is supposed to meet the federal environmental standard for agricultural use: a daily average of 2,000 fecal coliform parts per 100 milliliters.

But water-quality testing conducted by the Star shows that San Carlos’ oxidation lagoon is inconsistent, with its effectiveness varying dramatically depending on the volume of waste flowing into the lagoons.

In the busy tourism month of August, the oxidation lagoon was overflowing into an adjacent meadow, with wastewater from the lagoon filling the grasses, drawing wild horses that drink there.

Water samples taken on Aug. 16 from the final “clean” pond had fecal coliforms numbering 78,000 parts per 100 milliliters, according to the analysis done by CIAD Guaymas.

That’s nearly 40 times the daily threshold under Mexico’s federal environmental standards. (Over the course of a month, fecal coliform levels must average under 1,000 parts per 100 milliliters to comply with the standards.)

But water-quality testing improved dramatically six weeks later, when the lagoon wasn’t overflowing into the meadow:

A second set of water samples, taken from the oxidation lagoon’s “clean” pond on Sept. 27, tested well within federal standards: 450 fecal coliform parts per 100 milliliters.

Polluted lagoon
Like Guaymas, San Carlos relies on an oxidation lagoon to treat its wastewater, but the oxidation lagoon hasn’t been maintained in years. Image by Guillermo Soberón Tirado. Mexico, 2021.

Samples taken and tested on Nov. 3, when the lagoon’s water level was noticeably lower than previous tests, showed fecal coliform levels of just 15 parts per 100 milliliters.

The results suggest wastewater volume generated in late September and November was lower than in the busy summer months, allowing the oxidation lagoon to do its job effectively, García Hernández said.

But it also suggests the oxidation lagoon will become increasingly ineffective as San Carlos’ population grows.

Getting sick while golfing

Despite the inconsistency of San Carlos’ oxidation lagoon, the “treated” wastewater is still used to irrigate the golf course at the San Carlos Country Club.

Former CEA regional director and Guaymas native Roberto Romano said that during his tenure, in 2016, he was living in the Country Club when residents started complaining about sewage smells.

“Many people left the San Carlos golf course because of the smell,” he said. “They were getting sick.”

That year, Romano secured state funding for the San Carlos oxidation lagoon to be cleaned out: the bottom dredged to deepen the lagoon, and overgrown vegetation cut back. That modest effort greatly improved the lagoon’s performance and eliminated the smell on the golf course, he said.

If that type of maintenance were done annually, the lagoon could stay in good working condition, he said.

“It would take less than 1 million pesos (about $46,000) every year to maintain the oxidation lagoon,” Romano said. “It’s not drinkable water, but it can be perfect water for irrigation, if it’s maintained.”

Cattle graze
During the summer in San Carlos, the beach town’s wastewater treatment system — an oxidation lagoon with three ponds — overflows into an adjacent meadow. Horses often visit to drink the overflowing water there, which tested at 78,000 fecal coliform parts per 100 milliliters, based on samples taken by the Arizona Daily Star on Aug. 16. That’s nearly 40 times the federal daily standard for safe agricultural use of wastewater. Image by Emily Bregle. Mexico, 2021.

San Carlos Golf Club owner Lenny Manzon declined a request to be interviewed about the current quality of the irrigation water on the golf course.

“Supposedly, it’s gray water, not black water,” he said when approached at the golf course. He directed any further questions to the CEA.

Money problems

While the CEA at the state level operates the water and sewer systems in Guaymas, San Carlos, Empalme and Vicam, those local CEA companies are each audited separately — and their financial performances are miles apart.

The CEA in San Carlos, with higher water rates and a high percentage of users who pay their water bills, is operating in the black, according to a 2020 audit.

But the CEA in Guaymas is financially broken, former directors say. Last year, CEA Guaymas recorded a loss of $29 million pesos, or $1.3 million, according to a 2020 CEA Guaymas financial audit. In 2019, the loss was $23 million pesos, or $1 million.

The CEA’s units in Guaymas, San Carlos, Empalme and Vicam have accumulated a total debt of nearly $325.2 million pesos, about $15 million, due to unpaid water bills.

The financial problems at CEA Guaymas have a few main causes, according to former CEA directors:

• Forty percent of the CEA’s primary product — the potable water that is transported from Obregon, 120 kilometers from Guaymas — is lost, largely because of leaky pipes. Some level of loss is expected; in the U.S., about 15% of potable water is lost to evaporation and natural processes, Ahumada said. But a 40% loss is an unsustainable waste of a scarce resource, he said.

• Too many users in Guaymas fail to pay their water bills, and water rates are far too low compared to the cost of producing and transporting the water, said former state CEA director Sergio Avila in an interview. During the pandemic, only 19% of Guaymas users paid their water bill, compared to 60% before the pandemic, Cruz said. Payment rates in San Carlos are closer to 90%, even in the pandemic, he said.

• The CEA must negotiate with two powerful worker unions who have made aggressive demands, leading to an inefficient and oversized workforce, former directors said. Ahumada said the CEA in Guaymas, San Carlos, Empalme and Vicam could operate efficiently with half as many workers, 170 of the current 350.

Overflowing area of sewage in neighborhood
An arroyo intended for stormwater drainage is filled with raw sewage from overflowing manholes across El Rastro neighborhood. This arroyo empties into a stream that flows directly into a Guaymas bay. On Sept. 13, the Star took water samples from the stream to be tested for fecal coliforms, the type of bacteria found in human waste. Results showed 14 million fecal coliform parts per 100 milliliters in the stream. The federal environmental standard for safe discharge of wastewater into national bodies of water is 2,000 fecal coliform parts per 100 milliliters. Image by Guillermo Soberón Tirado. Mexico, 2021.

Union power

Three CEA regional directors point to the two unions that represent CEA workers as partially responsible for CEA Guaymas’ financial woes, and delays in urgent repairs.

CEA Guaymas has two unions: one representing front-line workers, and another for higher-level engineers and technicians, Romano said.

Seventy percent of CEA Guaymas’ spending goes to worker payroll and bonuses, Romano said.

Romano described situations in which an electrical problem shuts off a sewage pump over the weekend. Under union agreements, only a worker from a particular union can flip the switch to turn the pump back on, leading to unnecessary delays in stopping sewage flows, he said.

Romano said in his 4½ years as CEA regional director, there were six labor strikes.

“Imagine the energy, the time that demands on the administrator,” he said. “It’s very exhausting.”

But CEA workers say that without the unions, they wouldn’t even have uniforms or protective footwear.

Guaymas resident Antonio Chavoya left the CEA after 29 years in 2020, frustrated by never having the tools to do the job, including working vehicles with good tires and fuel in them. He now works security at Ley supermarket.

The union secured “salary increases, Christmas bonuses, first aid kits, waterproof boots,” he said. “The union got all of that for us.”

The lack of payment from users is another complex issue.

“The water company is supposed to be autonomous, self-sustaining. But it’s not,” former CEA regional director Romano said. “Why? Because people don’t pay for the water.”

A salon owner built a ramp for customers to get in
A salon owner in downtown Guaymas has set up a ramp across a raw sewage stream to keep customers’ feet dry. Sewage floods in downtown Guaymas were constant over the summer, leaving residents sickened with gastrointestinal distress, headaches and stinging eyes. Image by Emily Bregle. Mexico, 2021.

Many in Guaymas don’t pay because the potable water and sewer service is poor, he said. But without that income, there’s little chance of the CEA having the resources to improve service, he said.

“It’s a vicious cycle,” he said.

In addition to income from user fees, CEA Guaymas gets a state subsidy to help cover its expenses, mostly payroll and energy costs, according to a statement from the current CEA administration in Hermosillo, the state capital. This year, that subsidy will be about $83 million pesos, or $3.8 million. But it’s not enough to cover needed maintenance and other expenses, the statement said.

Users also have doubts about whether their money is going toward improving service, or whether it’s being mishandled by corrupt public officials, Guaymas state representative Orduño said.

“The main action should be to regain the trust of citizens, to convince them that there will be no more corruption, that their payment will be used to improve the water and sewer service,” he said. “Achieving this, there will be a flow of capital with which to maintain the pumping equipment in good condition.”

Broken sewage pumps lead into town
In downtown Guaymas this summer, broken sewage pumps meant raw sewage poured from worker-access points like this manhole in the El Rastro neighborhood on Aug. 17. Image by Guillermo Soberón Tirado. Mexico, 2021.

Energy expense

Guaymas’ topography is mountainous, requiring a costly network of sewage pumps to bring residents’ wastewater over steep hills to the city’s only wastewater treatment system, an oxidation lagoon known as “La Salada.”

The lagoon, which even CEA leaders now admit is inadequate, is the only treatment the wastewater receives before it’s discharged into the sea.

Former CEA regional director Ahumada pointed to massive energy costs needed to operate the sewage pumps. Each month, Guaymas spends $5.5 million pesos, or roughly $252,000 — almost half its monthly income from user payments, he said — on energy expenditures to serve its 60,000 contracted users, he said.

Compare that to the $6 million pesos spent in the city of Obregon, which has 230,000 domestic users but much flatter terrain, Ahumada said.

“We’re talking about one-quarter of the users, but almost the same energy costs,” he said.

With planning, the energy expenditure could be reduced, Ahumada said. Guaymas’ network of sewage pumps must work hard to move sewage over steep hills; much of that sewage from the densely populated north end of Guaymas travels six hilly miles to reach the oxidation lagoon at the southern side of the city.

A wastewater treatment plant on the north side — and ideally, two additional plants in other areas of the city — would significantly reduce the city’s energy expenditures, Ahumada said. It would also reduce the volume of wastewater flowing to the overtaxed oxidation lagoon in south Guaymas, he said.

Filing a report futile, some say

In response to a public record request, the CEA shared a database of sewage-leak reports received in Guaymas over the last four years. The database shows a steady increase from 1,024 reports in 2017 to 1,474 reports in the first eight months of 2021, aside from a dip to 829 during the unusually dry year of 2020.

Those numbers surely understate the extent of the problem, local residents say.

Many no longer make official complaints to the CEA. Some call friends who work at the CEA or approach CEA workers on the street for help.

Others have given up completely. Leaning out of his front door in the El Rastro neighborhood in downtown Guaymas, Hector Montoya describes an “unbearable” sewage situation outside his doorstep.

Like many others, he no longer makes reports to the CEA.

“Sometimes they fix it, but it just comes back,” he said.

While the sewage flooding has been worse this summer, which got a healthy level of monsoon rain compared to 2020’s dry summer, he says the sewage has been a problem for the 15 years he’s lived there.

“All of it is flowing to the sea,” he said. “It’s not right, but what can you do?”

The stink 'turns our stomachs'

The stream of sewage next to Montoya’s house originates from a manhole cover in the alley next to his home. Someone has arranged a series of concrete blocks as steppingstones for pedestrians to use when crossing the stream.

After crossing the main road, the sewage flow eventually joins a concrete arroyo, wet with sewage from other overflowing manholes in the neighborhood.

The stream continues down the arroyo toward the sea, passing a lonely basketball hoop and flowing parallel to a large cemetery before crossing under a busy overpass.

At this juncture, the sewage passes a Six convenience store, where Monica Castro works long hours amid the sickening smell.

In late August, Castro wasn’t only one dealing with the sewage in the arroyo. Just up the street, another stream had been spilling from a manhole cover for two months, drenching the road in front of her workplace. Her store is now filled with flies and sometimes she doesn’t eat all day because of the smell, she said.

“When it’s very hot, the stink permeates inside the store and turns our stomachs,” she said in Spanish. “We are disgusted. The boy who helps me in the afternoon was vomiting, because he couldn’t bear the smell.”

A woman stands in front of shelves in a store
Monica Castro works long hours at the Six convenience store, where she had to deal with overpowering odors from two major sewage flows near her store in August. Image by Guillermo Soberón Tirado. Mexico, 2021.

CEA workers came once in two months, but whatever they did made no difference: The sewage trail in front of her store is still flowing, she said.

But Castro doesn't blame only the CEA. She also blames residents who throw their trash into the street, clogging the infrastructure.

“It’s a health emergency, of course,” she said.

The Star tested samples from the waste-filled arroyo that was flowing toward the bay and confirmed it to be raw sewage, with 14 million fecal coliform parts per 100 milliliters.

The Star also sampled water from along the shore of the bay into which the sewage flowed. The results showed more than 240,000 fecal coliform parts per 100 milliliters. That’s more than 100 times the federal standard for wastewater discharges into national waters.

“Oh my god, that’s really high,” said Elsa Coria, a veterinarian who runs the Wildlife Rescue, Rehabilitation and Research Center, or CRRIFS, in San Carlos. Coria lives in the San Bernardo neighborhood, located near the contaminated bay.

More research is needed about the impact of sewage on marine life, but in the south of Mexico, fecal contaminants have been shown to damage coral reefs, she said.

Other pollutants, like heavy metals and insecticides, have been shown to cause tumors in sea turtles, like those CRRIFS rescues and releases into the sea each year, she said. Less is known about the impact of sewage, she said.

Coria wishes more people would remember how interconnected human health is with that of the animals in their environment.

“We are part of a net. We are not separated from the environment,” she said. “Everything we do to the environment is reaching us.”



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