Mayor Eduardo Paes says the 2016 Olympic Games will change Rio de Janeiro for the better, thanks to 27 “legacy projects,” including new highways, subway stations and sanitation systems.

He is proud of an ambitious public-private partnership to build a sewer network for 1.7 million people in the city’s western zone, where waste is largely flushed untreated into storm drains and stinking rivers and canals. The area, called AP5, covers almost half of Rio.

But although the new network has reached 19,000 homes, only one-fifth of them have actually connected to it. Some residents in low-income areas complain that the roughly $80 cost to hook up to the system is too high. Others simply do not think that the project, which is supposed to eventually serve about half a million homes, will succeed.

Instead of becoming a sanitation solution, the project is underscoring Brazilians’ lack of faith in their government, which has a poor record on delivering public services, and the private sector.

“People think the sewage was never treated and that it never will be treated, so they don’t believe in the project,” said Samuel Farias, 46, a sanitation technician for Foz Aguas 5, the consortium of construction and sanitation companies that is operating the project.

Brazil urgently needs sanitation improvements — only 39 percent of its sewage is treated, according to the Trata Brasil Institute, a nonprofit group that conducts studies on water and sanitation. Lack of proper sewage management is blamed for health problems such as acute diarrhea, hepatitis and skin infections, especially in children.

In 2011, the Rio city government, which had been responsible for the sewer system in AP5, awarded a 30-year contract to Foz Aguas 5 to take over the services in the area and build a new network. The project became part of the government’s promised improvements associated with the 2016 Olympic Games. In June, an Olympic complex in Deodoro, a gritty neighborhood, was connected to the network.

Foz Aguas 5 has committed to spending about $640 million and building 10 treatment plants over 30 years. So far, just one existing plant is being expanded. Sandro Stroiek, president of the consortium, said it has more than doubled the percentage of sewage treated in the area, to 12 percent, largely by repairing old pipes and equipment.

But the consortium is facing an unexpected hurdle: customers who do not seem to want the service.

One reason that residents are skeptical: They say that they have been billed for years for sewage services but that the waste was simply carried off from their homes and never properly treated.

Resentment runs particularly deep in Campo Grande, an area on Rio’s western fringe that is included in the project and is riven by open-air concrete drains and small rivers that have effectively become open sewers.

“The population pays for a service that is not provided,” said Mauro Pereira, president of a branch of the Brazilian Bar Association in Campo Grande.

A ‘big challenge’

About 40 percent of residents in the AP5 area do not pay any bill for sewage management, even though their waste is flushed into rivers and drains like everyone else’s, officials say. Some have irregular connections to the network; others simply are poor or know they can get away with not paying.

Many of those residents are worried that they will have to pay if they hook up to the new system, said Farias, the sanitation technician, and believe they cannot afford it — even though there are subsidies for low-income residents.

According to a 2015 Trata Brasil survey, 3.6 million people out of 82 million in Brazil’s biggest 100 cities are not connected to available sewer networks. Most did not want to pay the bills.

Many residents complain about the fee — around $80 — that plumbers charge to connect their homes to the new sewer pipes in Rio. That is almost half the official monthly minimum salary.

In Magalhaes Bastos, a neighborhood near Deodoro where the new network is being installed, Francisco Oliveira, 63, said the company should have paid to connect his house to the system. He and other residents said they had been threatened with fines if they did not connect. “People are doing it because they are intimidated,” he said.

Ilka de Conceição, 74, another resident, said that the work had been left unfinished in her street and that she didn’t know if it would even be completed. “I am not going to do the connection,” she said.

Foz Aguas 5 says it is trying to educate consumers on the new system and is working with Rio authorities to provide subsidies for the interconnection. It also offers free classes so residents can learn to do the connection work themselves, instead of paying a plumber.

“This is my big challenge, and I am worried about it,” Stroiek said. Even so, he said, the company will meet a deadline to treat one-third of the area’s sewage by May 2017.

‘AP5 is going very slowly’

The consortium took over the area’s sewage services from ­CEDAE, a utility company controlled by the regional government that handles the rest of Rio’s sanitation.

Isaac Volschan, a professor of environmental sanitation at the Federal University of Rio de Janeiro, said that getting private companies involved in the area’s sanitation made sense because there was not enough public money to pay for it.

“We will not advance just using public investment,” he said.

But Wagner Victer, president of CEDAE from 2007 to 2015, said it had been more efficient than the consortium in building sewer infrastructure in neighboring West Rio areas, where the Olympic Park and Olympic Village are situated.

“AP5 is going very slowly,” he said.

CEDAE, however, has been heavily criticized for pollution in Rio’s Guanabara Bay, where Olympic sailing races are scheduled this summer. The new consortium says that by the end of 2016, 17 million gallons of raw sewage a day from AP5 will no longer flow into the bay.

In Campo Grande, tens of thousands of residents sued ­CEDAE several years ago, arguing that they should not have to pay for sewage treatment services they did not receive.

Many won rebates and were exempted from charges. In 2013, however, a higher court ruled that it was legal to charge for sewage services because the waste was removed, even if it was not treated. The new network is not due to reach Campo Grande until 2017.

On a recent day, Alexandre Nunes, 61, walked down a Campo Grande street holding a bill he had just paid for water and sewage treatment.

He pointed to a pungent waterway where a brown snake had just slithered out of some reeds. “It all goes there,” he said.

Nunes said Campo Grande
had received one benefit because of the Olympics — a bus rapid-transit line.

“Sewage, no,” he said, expressing skepticism that the new project would ever be fully implemented. “Don’t even think about it.”