KATHMANDU, Nepal—As the sun sets over central part of this city, young Nepali men and women gather at the Tundikhel's northern edge to collect drinking water for their families. The large park at the center of Kathmandu has served many purposes throughout its history: It was a military parade ground, a horse track, a cattle-grazing ground and a concert venue. These days, it's a refugee camp of sorts, hosting thousands of people who either lost their homes during Saturday's earthquake or believe them to be unsafe due to structural damage. It's also the potential epicenter for what many predict to be the aftershock to the quake's aftershocks, a sort of second disaster: the looming water crisis. The first few days in the government-constructed camp were difficult. Thousands and thousands flocked to the site after the first earthquake, which registered 7.9 on the Richter scale. Water was delivered in an Army tanker just once a day, says Samsad Ansari, a 22-year-old student who has been living here with his family since Saturday, when their nearby home was destroyed. At first, he would have to stand in line to fill the family's empties; now, in addition to the daily delivery of Army water, there's a tank that Ansari and others can use at their leisure. "It's much better," he says. For now, the camp seems fairly stable and optimistic. The smells of dinner cooking on various makeshift stovetops fill the air, and children sit outside on the grass, singing songs and playing clapping games. But when I ask Sarina Prabasi, a Nepal native who is CEO of the nonprofit WaterAid America, whether the country will rebound quickly, she replies, "Not to sound pessimistic, but I think we're going to see it get worse before it gets better." She and many others believe the core necessities for healthy living could soon be in short supply here. Lack of water, in particular, could be a major problem moving forward. "The town water supply is completely broken down," says Arjen Naafs, the South Asia regional technical adviser for WaterAid. Although the water source made it through the earthquake unscathed, the piping was significantly damaged. "Most of the taps are not working now," says Ritesh Hada, a project coordinator for the Nepal operations of Splash, a nongovernmental organization focusing on safe water. In addition, debris has blocked drainage across Kathmandu, further restricting water movement through the city. Tankers have been commandeered by the army to transport the water into the city, but it's slow going. Trucks might sit in the refill line for hours, and distribution is happening at a snail's pace, and with much confusion. At Tundikhel, for example, no one knew when the water would arrive. "Even before the earthquake, water was quite scarce," says Hada. Most Kathmandu residents typically buttress their tap supplies with purified water bought from private distributors. Those who could not afford to buy water would gather daily at the 389 beautifully carved ancient stone spouts that dot the city. But in recent years these spouts have fallen into disrepair, and at least half have gone dry. In the days following the earthquake, the price of bottled and purified water in Kathmandu has doubled, leaving more people priced out of this alternative source. Ultimately, though, the fear is not that people will die from thirst—it is that they will begin to forgo hygienic-water use and drink liquids that will make them ill. For years, Nepal has had major sanitation problems. According to the World Health Organization (WHO), just 37 percent of the country's population has access to adequate sanitation facilities. It's estimated that 60 tons of household wastewater (from toilets, sinks, showers) is dumped into rivers in Kathmandu every day. From there, it travels downstream and to lakes that make up the city's water source. In rural areas and even in parts of the city, open defecation has been a problem for years. Naafs worries that the developments of recent years (access to quality sanitation facilities rose to 37 percent from 34 percent between 2010 and 2012, for example) may be undone during the earthquake's aftermath. "Nepal was making progress getting open-defecation-free," Naafs says. "Now people are scared to get into their homes." For people forced to live outside, their waste has to go somewhere. The problem is that when people "abandon their normal hygiene habits," waste can easily get into someone else's drinking water.This is clear at the Tundikhel camp, where children throw empty soda bottles at each other and then pick them up off the ground, brush off the dirt with equally dirty hands and fill them from the water tanker's tap. "We are going to get a cholera outbreak somewhere," says Naafs. After the 2010 earthquake in Haiti, a widespread outbreak of the waterborne bacterial disease infected more than 700,000 people and killed 8,646, according to the WHO. And a cholera epidemic in Nepal would not be unprecedented: Last year, 600 people caught cholera, and in 2009 a major outbreak affected more than 300,000 people. Worse still, both those outbreaks came during monsoon season, which is now on the horizon. "With the rain, there is flooding and landslides, and whenever there is flooding there are major sanitation issues," says Prabasi. "And we are not going to be able to rebuild before the monsoons."