LIMA, Peru — “We are the poorest of the poor. Why do we have to pay the most?” asks Diana Ureta as she washes a bucket of potatoes using turbid water fetched in a jug from a discolored plastic barrel beside her front door.

Two chickens peck at the uneven dirt floor while her 4-year-old daughter, dressed in a baggy, stained T-shirt, watches her mother ferrying yet another quart from the barrel back to the kitchen.

Like most of her neighbors here in the Lomo de Corvina neighborhood of Villa El Salvador, a gritty suburb sprawling on the dusty Andean foothills southeast of Lima, the Peruvian capital, Ureta has neither running water nor sewerage.

Cooking and cleaning up afterward are one of many daily ordeals. The family, which includes her 38-year-old mototaxi driver husband Nico Catunta, three children, two nephews, and Catunta’s 78-year-old father, all share a single “dry” toilet, essentially a hole in the ground. Bathing is in a cement lined tub set in the ground, with cold water given that the family has no electricity and cannot afford gas.

Ureta and Catunta are among an estimated 1.2 million residents in this city of 10 million who depend on an unregulated fleet of privately owned tanker trucks for their water needs. The water supply challenge is compounded by Lima’s geography: it is the world’s second most-populous city, after Cairo, located in a desert.

The trucks pass daily through the neighborhood, selling water at around 20 sols (just over $6) per cubic meter – compared to the 1.3 sols per cubic meter that SEDAPAL, the Lima water utility, charges more-affluent consumers for potable tap water.

The trucks’ water is often untreated, sucked up from any available source, including streams and even ditches. Some owners conscientiously keep the insides of the tankers clean. Others do not. “We have to boil the water we use for cooking or to drink,” says Ureta, 30. “That is another cost. We use firewood and it takes up so much time every day.”

Ureta and her family’s story is typical of some 40 percent of the world’s population, roughly 3 billion people, who suffer water scarcity in some form, according to the United Nations Development Programme. It’s Sustainable Development Goals aim to ensure “universal and equitable access to safe and affordable drinking water” for all by 2030.

The number of people without reliable access to clean water is expected to rise further before it eventually falls. Meanwhile, 2.4 billion people lack access to toilets or other basic sanitation. No wonder then that 1.8 billion rely on water sources that are contaminated with fecal matter, according to the multilateral agency.

The result is a global public health crisis, with high levels of malnutrition, anemia, diarrhea and other diseases directly attributable to communities’ enforced reliance on unclean water sources.

Day Zero’ Approaching for Many Countries

Climate change, a global population boom and rapid urban growth have created an unholy cocktail of challenges that makes the UNDP objective “very ambitious,” says Leo Heller, the U.N. Special Rapporteur on Water and Sanitation. “We will have to see in a few years’ time if we are on track.”

Yet despite that, Heller insists, the problem is not insufficient water supplies but rather inadequate public policy with municipal and national governments frequently failing to prepare for the hydrologically stressed present, never mind the future.

The most obvious current example is Cape Town, which is now forecast to hit “Day Zero” – when the South African city runs completely dry – sometime next year.

However, numerous regions around the world, particularly in the Middle East, sub-Saharan Africa and various parts of Latin America from Mexico to Bolivia, are all facing similar problems. So, too, is a broad swath of the Southwestern United States, particularly Arizona, California, and New Mexico.

In each area, the challenge is distinct and Day Zero may yet be a long way off – but it will eventually arrive unless authorities, business and citizens manage water use in new and more strategic ways.

“What happened in Cape Town?” asks Heller. “Governments cannot say that climate change is a surprise. We have known this was coming for a long time. This is a question of planning. Good infrastructure and systems are essential.”

“We know that the quantity of surface water and groundwater fluctuates over the seasons. That is only going to get worse going forward. We need to have the flexibility and adaptability to cope with that.”

Few places may be as hydrologically complex as Peru. As the source of the Amazon River, the country is unusually blessed with water resources. However, roughly two-thirds of its 31 million people live on the other side of the Andes, on the arid coast, where there is less than one inch of average annual rainfall.

Indeed, the Incas and other large pre-Columbian population centers were located in the mountains, where there is no shortage of precipitation. It was only thanks to the conquering Spaniards, with their limited environmental awareness and need for a Pacific port to transport gold and silver back to Europe, that Lima was founded in the dust beside the Pacific.

That problematic historical legacy has been compounded in recent decades with massive migration from Peru’s mountains and jungles to the capital. Many of the impoverished new arrivals end up, like Ureta and Catunta, squatting on unoccupied and marginal land on the urban outskirts.

That has created a nightmare for SEDAPAL, which is now scrambling to catch up with the shantytowns springing up on often steep terrain around Lima. “Putting a pipe up to the top of a hill is difficult and costly,” says Yolanda Andia, the utility’s head of production and distribution.

“It’s not just the pipe. You need a series of pumps as well. Water doesn’t run uphill. If it were up to SEDAPAL, we would have people settling in a more ordered fashion.”

Currently, Lima’s people require 27 cubic meters of water per second, yet the cities’ three seasonal rivers have an average flow of just 23 cubic meters per second. Although rainfall patterns in the watersheds that supply Lima, high up in the mountains, are declining and glaciers vanishing, SEDAPAL is investing nearly $7 billion in the next four years to bridge that gap.

New infrastructure will include a desalination plant on the coast just south of the capital, and more high-altitude reservoirs to store precipitation from the rainy season that approximately coincides with the northern winter.

Yet for many of Lima’s poorest residents desperate for potable tap water, bureaucracy is actually a bigger hurdle than climactic limitations.

Land Tenure a Growing Problem for World’s Poor

When Catunta first arrived at Lomo de Corvina a decade ago, he bought his 960-square-foot plot of land for 4,000 sols (roughly $1,200) from a neighbor. He then built the family’s flimsy wooden single–story home with his own hands.

But the seller – who left the community years ago – had never legally owned any of it. This kind of land trafficking among the poor is common in Peru and elsewhere in Latin America. Indeed, most of Catunta’s neighbors fell for the same trick. And SEDAPAL can only install water to properties whose owners have valid documentation.

Catunta, Ureta and their neighbors are unable to apply to the municipality for titles to the land based on having inhabited it for years because the local zoning is for agricultural and industrial use. That has even ruled out the classic fudge in some developing nations, where it is routine for the poor to squat on unoccupied land, of handing out “certificates of possession” in lieu of land titles.

As a result, 28,000 residents of Lomo de Corvina have banded together to contract with a Spanish company for $100,000 to carry out the studies necessary for the municipality to change the local zoning to residential – the kind of study that normally would be carried out by a public agency at no direct cost to local communities.

“Land tenure is a big problem around the world,” says Heller. “Many governments argue that if you don’t have titles you are not entitled to basic services. This is both discrimination and a violation of human rights. Access to water and sanitation is a human right and should not be conditioned on whether or not you own the land on which you live.”

For Ureta and Catunta, the notion that clean, affordable water is actually their right is something of a novelty. “We just want it because it will make our lives so much easier, and because it will be cheaper,” she says as she heads with an empty jug yet again back to the plastic barrel.