It's something of a ritual. Every time it storms, Rudy Barajas grabs an umbrella and trudges to the end of his street in southwest Houston to see if raw sewage is gurgling out of a nearby manhole on Wilcrest.

The longtime Alief resident works for a civil engineering firm, so he knows how sewer systems work - or, as is too often the case in Houston, don't work. If the rain has been particularly heavy, Barajas slogs back inside with a familiar message for his family.

"Look, we have to be real careful - we don't want to flush the commode, don't wash, use a limited amount of water," he said. "My grandkids, they're 5, 6 and 7 years old. Whenever it rains hard, they'll come and ask me, 'Is it OK to flush the toilet?' They already know there's a problem."

Houston's long-running struggle with sewer spills spares few corners of the city, leaving residents from Gulfgate to Acres Homes unable to shower or flush for days while crews clear blockages, or forcing them to buy gallons of bleach to scrub their bathrooms after backups.

Barajas' ZIP code, 77072, has experienced the second-highest number of sewer spills of any local ZIP code in recent years. In his case, it appears water meant for the storm sewer is entering the sanitary sewer; often, tree roots crack old pipes.

City sewer spills have disproportionate impact

The neighborhoods most likely to feel the consequences of Houston’s long-running struggle with sewer overflows are disproportionately home to low-income and minority residents, a Houston Chronicle analysis of city data shows. The four dozen zip codes with above-average rates of raw sewage spills also have higher poverty rates and larger concentrations of Hispanic or black residents than the city as a whole, a trend that is even more pronounced in the 10 zip codes with the most spills since 2009, when officials say they began keeping reliable data.

Houston's roughly 840 annual overflows have drawn scrutiny from the federal Environmental Protection Agency, whose regulators worry about raw sewage degrading water quality. As in dozens of other cities, Houston is negotiating a so-called "consent decree" with the EPA that would specify projects aimed at reducing spills by upgrading pipes, ramping up maintenance and educating the public on how to avoid clogging Houston's 6,700 miles of sewers. The cost could top $5 billion.

Unequal impact

Particularly troubling for environmental justice advocates, however, is that city data show the neighborhoods most likely to feel the consequences of aging, inadequate or poorly maintained sewer pipes are disproportionately home to low-income and minority residents.

A Houston Chronicle analysis of the 46 city ZIP codes with above-average rates of sewer overflows shows two-thirds of these areas also have higher poverty rates and larger concentrations of Hispanic or black residents than the city as a whole.

This trend is even more pronounced in the 10 ZIP codes with the most sewer spills since 2009, when city officials say they began keeping reliable data. In all 10 areas, household incomes are below the citywide median, and poverty rates exceed the citywide level in nine of them. In only one of the 10 ZIP codes do white residents come close to matching their share of the citywide population.

This data includes only the spills caused by problems in the sewer pipes city crews are responsible for maintaining, not the private pipes that connect from residents' homes to the city sewer.

City officials declined comment for this story, citing the ongoing EPA negotiations. Public Works and Engineering officials have previously said, however, that many of the city's sewer pipes were upgraded under previous state or federal decrees, and that their primary focus now is on better maintaining and cleaning the pipes to prevent blockages.

Robert Bullard, dean of the school of public affairs at Texas Southern University, took one look at a map of Houston's sewage spills and shook his head, ticking off the struggling areas he has studied for decades as a founding voice in the environmental justice movement.

"The same neighborhoods we're talking about are the neighborhoods where, historically, the services have bypassed them. This is not a new phenomenon. But what makes it a real story is we're talking about 2016," Bullard said. "It reinforces this whole concept of environmental injustice and the impact of unequal distribution of resources, and the allocation of dollars based on race and class. You can predict where the worst problems are."

Houston's unequal distribution of sewer spills does not necessarily mean City Hall is making discriminatory decisions today, Bullard said. Pipes last decades, he noted, so some neighborhoods facing problems today might be playing catchup from past neglect.

City data show some low-income and minority neighborhoods with sewer problems do not necessarily have older pipes than other areas, however, which advocates say suggests the city still has room for improvement.

Angry residents

As for Barajas' neighborhood, he said city officials have told him a project is coming to replace the pipes. Whenever that comes, he said, will not be soon enough.

"This just shouldn't be happening," he said.

Northeast Houston resident Sedonia Joiner is similarly fed up.

Joiner said a backup earlier this month - the 10th she's seen in 15 months of renting at the Crofton Place Apartments - ruined her clothes and furniture, and gave her a stomach flu after she and a neighbor tried to clean it up. It also brought her cumulative cost for cleaning supplies to about $400.

City data show an estimated 12,000 gallons of raw sewage have spilled at the complex in the last seven years. The registered owners of the property could not be reached for comment.

City staff this month held a poorly attended meeting asking tenants not to flush diapers, wipes or towels into the pipes, and not to pour grease in the sink, Joiner said. She puts much of the blame for the problem on ignorant neighbors, but Joiner said the city also must do its part. Her ZIP code, 77016, experiences the third-highest number of sewer spills.

"They need to get more crews out to take care of the system. Instead of certain areas, it needs to be all over," Joiner said. "It's very hazardous. People walk through that kind of stuff. It's unsanitary. They need to do a better job."

EPA scrutiny

Mayor Sylvester Turner has acknowledged the ongoing EPA talks, but it's unclear whether the negotiations have explicitly addressed overflows in Houston's poor and minority neighborhoods, as other consent decrees have.

Chicago, Cleveland, Memphis, St. Louis, Kansas City and Seattle, for instance, all agreed to pursue repairs in low-income and minority neighborhoods first in their decrees. St. Louis and Kansas City also agreed to help residents retire their septic tanks and connect to city sewer lines; some Houston residents still use septic tanks.

Whether Houston's looming decree mentions environmental justice or not, said Brent Fewell, an environmental consultant and former EPA official, the issue contributed to the EPA's scrutiny.

"The agency has many different targets to enforce against, but when any of those targets involves 'EJ,' that's the one that they are going to pick," he said. "A lot of communities simply have not paid much attention to these issues, so economically disadvantaged and minority communities a lot of times have been the ones to suffer the greatest consequences."

Environmental justice first gained traction with a 1994 executive order from President Bill Clinton, but experts say the EPA has greatly ramped up its focus on the issue in recent years.

A 2014 EPA plan, for instance, singled out city sewer spills as a top priority, saying they "often affect poor and minority communities by contaminating urban waters or causing sewage backups into their homes." The agency is now updating that plan and vowing to become even more aggressive.

EPA officials have not discussed their actions in Houston, but a regional spokesman did provide a brief statement.

"EPA is always looking at the impacts to people living in communities when discussing resolution to pollution problems," David Gray said, "and remains committed to solutions that benefit those most affected."

Fixing disparities

Local environmental justice advocates said they know citywide infrastructure failings can't be fixed overnight. What is important now, Bullard said, is keeping inequities in mind when deciding how the problem gets fixed.

"If you equally distribute the money, you will build on inequity because the money was not distributed equally over 40 years. That's how you got here," Bullard said. "So it means you have to fine-tune how you're going to spend these dollars to make sure you fund projects that will begin to correct some of these disparities."

Chronicle reporters John Harden and Matt Dempsey contributed data analysis to this story.