Juba, South Sudan - By 10am, the unforgiving morning sun begins to beat down on the dusty streets and mud huts of Hai Gabat, a neighbourhood in the east of Juba, South Sudan's capital.

Sam, a 45-year-old water seller from Uganda, has been up for four hours. He is busy securing the last of six jerrycans on to the rusty frame of his old, heavy bicycle.

Around him women, children and men gather beneath the sprawling boughs of a leafy tree, seeking shelter from the sun and filling dozens of yellow jerrycans with running tap water.

The cluster of taps is one of Juba's two UNICEF-installed water points, where water from the River Nile is treated with aluminum sulfate and chlorine before some 50,000 litres are pumped out daily for private and commercial use.

This small oasis offers a source of potable water in a city where access to safe water isn't readily available. Only 15 percent of Juba's residents are able to access municipal water. Much of the population is left vulnerable to waterborne diseases such as cholera, dysentery and the Guinea worm disease.

According to the United Nations, water scarcity affects more than 40 percent of the global population with 1.8 billion people worldwide drinking water that is fecally contaminated and some 1,000 children dying each day from preventable water and sanitation-related diseases.

Since June 2016, South Sudan has recorded 6,774 cases of cholera, including 221 deaths.

Sam, who did not want to give his last name, and his colleagues provide a vital service. They are an integral part of Juba's water system, given the job of delivering safe drinking water to some of the city's most vulnerable neighbourhoods.

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Dependence on mobile water vendors

Juba's water vendors start getting ready for their gruelling day's work as soon as the sun rises at 6.30am.

After paying their daily fee of just under $1 to use the water facilities, they fuel up on a breakfast of bread, eggs and tea at a nearby restaurant. Then they begin their rounds, which continue throughout the day. They only stop when the sun sets at 7pm.

South Sudan has plenty of surface and ground water potential, yet, according to an African Development Bank report, "access to water supply services is among the lowest in Africa".

Over the years, the state-run water services have increasingly deteriorated, with little government investment to expand the availability of water to households.

"People in this area depend on us," says Sam, barely audible against the roar of UN charter planes taking off from a nearby airport.

The Kampala-born water vendor moved to South Sudan five years ago, drawn to Juba by the promise of better work opportunities at a time when the newborn capital appeared to be flourishing.

That period was short lived. A violent civil war tore through the country just two years after its independence from Sudan. The clashes were triggered by a falling out between President Salva Kiir and his deputy Riek Machar in December 2013 and were followed by a renewed surge in violence in July 2016. Last December, a member of a UN commission on human rights said that a "steady process of ethnic cleansing" was under way.

The conflict has displaced some 3.5 million people and about two-thirds of the population are in need of humanitarian assistance. Around 4.9 million individuals are considered to be food insecure and 100,000 live in what the UN has called a "man-made" state of famine.

"There is only so much that humanitarian assistance can achieve in the absence of meaningful peace and security," Joyce Luma, head of the World Food Programme in South Sudan, said in a statement in February.

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The business of selling water

With the country's economic collapse and the spiralling costs of food, Sam can hardly afford to pay for his daily breakfast, let alone send money to his wife and five children in Kampala.

"I was a businessman in Uganda, I was buying and selling produce," Sam says.

"I need to eat a lot because it [delivering water] takes up a lot of energy," he says, pushing his bicycle briskly down a dirt road, his load too heavy to pedal.

The number of jerrycans worth of water sold each day depends primarily on the seller's strength, Sam says.

"There is no limit. When you have enough energy you sell more," he laughs. "The most I've made in one day is 500 [South Sudanese] pounds." That's equal to just under $3.50 on the black market for about 50 jerrycans of water at 10 pounds each.

"But with 500 you can't even eat. Saving [money] is a problem."

After a short walk through the Hai Gabat neighbourhood, Sam reaches the home of his second buyer. A young woman in a blue dress greets him from behind a makeshift wall of sticks and branches. The woman is head of a family of 10 and pays just under $1 a day for clean water, which she and her family use for drinking and cooking.

In order to save money, they bathe and wash their clothes with untreated water from the river. It's an alternative that does not come without its complications.

"While washing clothes in river water is not much of a risk provided they are sun dried and ironed, the risk of skin infections is high when one bathes in contaminated river water," says Sibonakaliso Mpala, water, sanitation and hygiene project manager for aid group World Vision.

With the agility of someone who has been doing this job for a number of years and the charm of a good salesman, Sam chats cheerfully with his clients while emptying the water into a large blue plastic barrel, before saying goodbye and returning to the cluster of taps under the increasingly hostile sun.

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Precarious water situation

Back at the water site, vendors refill their jerrycans.

"Since it was installed we've had clean water and the sicknesses cannot reach our homes. I feel safe," says 21-year-old Margaret Joan. Her child was recently sick with diarrhoea. "Now he's OK," she adds with a smile.

One of the vendors there is 27-year-old Lawrence Moghenzi, who came to Juba in 2011 from the Rwandan capital Kigali.

Like Sam, Moghenzi came to Juba after hearing about job opportunities. But Moghenzi is an electrician by trade, and soon discovered that in a country where only an estimated 1 percent of the population is connected to the national power grid, his skills were not in demand.

He soon found that he could profit from the city's dire water situation and that on a good day he could make up to $6. This, he says, allows him to travel home to visit his family.

Collecting water is free for private individuals, but vendors are required to pay a daily fee each morning.

While UNICEF provides water purifying structures and the government subsidises chlorine, one of the two chemicals used to treat the water, the vendors' fee is supposed to cover the cost of the second chemical.

Some vendors struggle to pay this fee, Moghenzi says.

"Our first problem is the supply of aluminum sulfate," he says.

It's getting harder for the vendors to earn money.

According to Sam, six years ago, one jerrycan sold for less than two South Sudanese pounds, versus today's 10 pounds.

"People don't have the money," he says. "It affects me because the money which I was getting, now I'm not. The [living] conditions are very hard."

The collapse of the South Sudanese pound has driven up prices, meaning more people are unable to afford to buy clean water and must increasingly rely on untreated river water. This has resulted in stagnant or dwindling incomes for the vendors and greater risk of diseases for people.

"Before the July 2016 crisis, more households could afford to buy treated water mainly for drinking and cooking," says Mpala of World Vision.

"Currently households are increasingly reliant on cheaper untreated water for domestic use including drinking and cooking."

But while most of the city's residents live far from water points, the people of Hai Gabat not only have daily access to safe water, they have also made a gathering place of the site, where they can chat while waiting for the cans to fill up.

A gaggle of restless children screech happily as they chase one another with filled water bottles, emptying them on each other's heads. Nearby, a mother with a tiny baby strapped to her back fills up a jerrycan and swiftly balances it on top of her head before turning to walk back to her home, clutching the afternoon's load of clean water.

Sam readies himself for the last delivery before his one-hour lunch break, after which he will work without stopping until the sun goes down and it becomes too dangerous to stay out on Juba's streets.