It is a windless 35 degrees in the dusty village of Rockville, half an hour north of Pretoria. Yet  every door and every window in the village is closed. All the residents are indoors. More astonishingly, there are no children in the street or playing in gardens. The children have been sent away.

"I sent my two children to Johannesburg because they were so sick here," says Themba Mkhize, an unemployed resident of the 2 000-strong community. "They would always rub their eyes and cough and have diarrhoea."

The trend is repeated along the street. Children who stay in this extension of Hammanskraal get sick. Some die. Many, who survive grow into sick adults. But those who go get better do not return. Mkhize sent his kids away in the late 1990s. They are now grown up.

"Now my children do not come back, not even for the night, because they get sick when they are here," Mkhize says.

Resident Dorothy Pole says: "The only time you can get people to come here is for a funeral."

The reason is right across the road from Rockville – the local sewage treatment plant. It is too small, too old and has not been maintained. The treatment plant floods and pollutes the neighbourhood every time it rains. And although the plant is finally being upgraded, for many people it is already too late.

Trouble breathing
Working his way through his black plastic bag of medicine for his tuberculosis, Mkhize says the treatment plant makes people sick with the dust that blows off it, or when it leaks sewage. "Even when I have trouble breathing and want air, I cannot open the windows because of the smell and the polluting dust," he says, sitting on his coach in the front room. In the background a fan is slowly circulating hot air.

"If you cannot afford medicine,  then you die – and I am dying," says Mkhize. If the local clinic runs out of medicine, as often happens, you have to buy your own, something Mkhize cannot afford.

When it rains, the sewage pipes and the treatment plant block up and flood the neighbourhood. The water comes halfway to your knee and can sit in yards for three days, people say. It is dry now, but a layer of white waste still covers the tufts of grass that thrive in the sewage.

Showing the water damage inside her house, where anything wooden is rotten and peeling, Madelene Thubane says the water makes people sick. "When the sewage comes my ankles get swollen and my joints are stiff," she says.

And although she pays R1 000 a month for municipal water, she has to buy R500 worth of bottled water every month. "If you put a cup of water on the table it will divide into layers of pollutants. And last week we found tapeworms in the water," she says.

Near the end of the long street bordering the plant, an old man, leaning heavily on his walking stick, says he has constant diarrhoea. Although he is unable to remember his name, he is still certain that the treatment plant is making him sick. "It kills," he says.

Expanded
Their ward councillor, Jabu Sibaya, says on the phone that the plant is not a problem: "I have never seen people that are not healthy because of [the plant], and if they are they did not come to me to complain."

The plant is being expanded because it is too small for the community, he says. But the community is contesting this because they say they were not consulted and the treatment plant did not get a water licence for the expansion before it started. The case is now in court.

The community worker helping the residents, David Leeuw, has done his own study of the 200 households. "I found a clear pattern where people had chest problems and diarrhoea. And they had this in levels much higher than in surrounding communities," he says in his file-jammed office.

The plant and sewage floods are the only thing that makes Rockville different – a fact recognised by other people in Hammanskraal who ridicule these residents as "living in shit", he says.

He also found that three or four members of most families living there had died in the past decade. Most of the children had been sent away to school because of their poor health, and quickly became healthier after they left, he says.

A local health practitioner, who does not want to be named, says the biggest local problems are upper respiratory infections such as tuber-culosis. "Diarrhoea is also common, especially in the children," the healthcare worker says.

Rockvilles
Strange skin infections, which nobody has been able to diagnose, are also common in babies. "Hammanskraal's water and sewage has always been a problem, and you see it in the problems that have to be treated."

There are many other "Rockvilles" in South Africa. The last numbers recorded by Statistics South Africa are from 2009. As many as 22 000 people died as a direct result of diarrhoea that year. Of these, 6 200 were under the age of five, and most were under a year old.

Incredibly, the Rockville sewage works did relatively well in the last Green Drop reports from the department of water affairs, with an average risk rate of 60%. But what this means is that 40% of the waste water it releases each year does not comply with safe levels. By comparison, the plant at Meyerton in southern Gauteng releases unsafe water 66% of the time.

In the whole country only one in 20 plants was given "green drop" status, meaning they were actually doing their job properly. Of the 881 plants, 153 were a critical risk and 221 were a high risk. Rockville is in the medium risk category.

A medium risk is still too high for people trying to survive in Rockville. For Pole it is simple: "The plant kills people."

SA's massive, massive problem

The United Nations Children's Fund uses diarrhoea as a measure of a country's water treatment infrastructure. Nearly 60 out of every 1000 children in South Africa die before the age of five – about 58 000 a year.

And the fund said that in developing countries most of these deaths are from pneumonia and diarrhoea, which kill 1.3-million children a year worldwide.

The South African Medical Journal investigated this and said: "South Africa is sitting on a health time bomb caused by outright neglect of its water and sanitation systems."

Dr Jo Barnes, a specialist in community health risks at the University of Stellenbosch, said that a chronic lack of investment in infrastructure was creating a big problem. Waste water treatment plants release partially treated water, which joins other waste in rivers. This is being piped to communities through ageing infrastructure and inevitably arrives at taps already contaminated by faeces.

"The whole environment where people live is contaminated," Barnes said. Any waterborne diseases, such as diarrhoea, are therefore given a chance to prosper, she said. "Investment has been ignored for at least a decade so now the plants are on the verge of collapse, and it will require a fortune to fix the problem."

Deaths from diarrhoea are recorded, but the affliction weakens people and makes them susceptible to other diseases. This makes finding the actual number of people affected nearly impossible. Wealthier people also go to private doctors, and their cases do not find their way into the statistics, Barnes said.

"This is a massive, massive problem – but one that people will not talk about. There are just a few angry people trying to raise awareness," she said.

The local and national government departments involved, despite having two days to reply, either said they were not involved or did not respond to questions in time. But in parliamentary questions in 2010, the department of water affairs said R23-billion was required to fix the problem.