Faced with chronic shortages of water from an overloaded municipal system, residents on the southern fringe of Mexico City are returning to one of mankind’s most ancient methods to meet their water needs – capturing the rain.

A project launched by two Mexican-American industrial design students from the Rhode Island School of Design has installed more than 1,200 rainwater harvesting stations in Tlalpan, a semi-rural and largely low-income borough where water shortages are particularly bad. Another 9,000 units are expected to be installed over the next four to five years.

According to a study last year by the International Renewable Resources Institute, an independent think thank in Mexico, more than five million residents of Mexico City – a sprawling metropolis of 22 million – grapple with severe shortages of water supplied through an aging pipeline network that has not kept pace with the city’s rapid growth and which draws water from diminishing aquifers.

Enter Isla Urbana, a non-governmental organization that hopes to help remedy the problem by setting up easy-to-use system that funnels rainwater collected on rooftops through a series of flushes and filters, before depositing the clean water into storage thanks.

Enrique Lomnitz and Renata Fenton, the driving forces behind Isla Urbana, came up with their plan after noticing that many Mexico City residents described water shortages as their most pressing problem.

“It became clear to us that rainwater harvesting had to be an integral part of sustainable water management in this city,” Lomnitz said in an interview with Fox News Latino.

Lomnitz, 30, the son of a Mexican and a Chilean-American, spent part of his high school years in Chicago before going to the Rhode Island School of Design, from where he graduated in 2006. He then moved back to his hometown of Mexico City, where he still lives.

“There are more people, and the same amount of water. Water is divided up and there’s less water,” he said, adding that the problem was aggravated by the fact that “many aquifers are not yielding as much water as before.”

Few areas are worse affected than Tlalpan. An estimated 83,000 of its residents are not connected to the water grid at all. Most others cope with sporadic shortages when the pipes run dry and residents have to buy water from delivery trucks that often fail to arrive on schedule.

“We have no water. We’re not on the system,” Tlalpan resident Miguel Gomez Flores said in an interview. “Sometimes they (the water trucks) take months. Once they took three months. Sometimes we’ve had to ask neighbors for a few buckets of water when things got really bad.”

Mica Velazquez Garcia, a Tlalpan woman whose family recently had a rainwater harvesting system installed in her home, echoed the complaint.  “We had to keep asking for the trucks every month, and they were often a month and a half late.”

With a water collection unit from Isla Urbana, that problem has now gone away. The captured rainwater, she said, is of good quality. But Isla Urbana recommends that people do not drink the water unless additional filters are installed.

Lomnitz says that rainwater harvesting on a city-wide scale, complementing the existing water supply system, would ease the burden on the government.

“The real economic beneficiary is the government. They don’t have to find water, highly subsidized water,” he said. “If half the houses have harvesting storage tanks, the other half would be able to get more from the grid.”

Isla Urbana estimates that the installation of 10,000 rainwater harvesting systems in Tlalpan would allow the government to save between 30,000 and 60,000 water truck deliveries, thus easing demand on the municipal system.

Estimates on how much of Mexico City's water needs could be covered by rainwater harvesting vary widely, from 30 to around 50 percent.

In the past, Mexico City water officials have expressed a measure of skepticism about rainwater as a viable source of water for the city, noting that the cost of the systems – which range from about $218 to $818 per unit – might put rainwater out of the reach of many families.

Yet Tlalpan residents who no longer have to rely on water trucks see no drawbacks.

Many of the rainwater harvesting systems in Tlalpan have been paid for by Iniciativa Mexico, a reality television show backed by Televisa, TV Azteca and other media organizations to encourage social entrepreneurship – Tlalpan residents only had to pay for the installation.

Rainwater harvesting has been implemented with varying levels of success around the world, particularly in Australia, where millions of people rely on rainwater as a primary source of water.

The practice has also been implemented on a large-scale in Germany, Thailand, India and Brazil. In the United States, several states, such as Texas, have introduced legislation to promote and regulate rainwater harvesting.

Bernd Debusmann Jr. is a freelance writer based in Mexico City.

Follow us on twitter.com/foxnewslatino
Like us at facebook.com/foxnewslatino