By Samira Mehta (C’21) and Pallavi Menon (C, W’21)

University of Pennsylvania

December 10, 2019


Imagine a day without water… from the simple flush of the toilet to that refreshing morning shower, water is a basic need and it impacts sanitation, hygiene, education, and health. Yet, according to a 2015 report from the United Nations, 2.1 billion people around the world (3 out of 10 people) lack access to clean drinking water. Currently, 11 cities around the globe are at risk of reaching Day Zero, or the day when taps run dry. Amongst them is Mexico City, a city that is flooding but is still running out of water.

Isla Urbana at Penn students assess Rosa’s roof and strategize on how to best adapt the system to fit the conditions of Rosa’s house.

Unsustainable water management practices have put Mexico City at risk of running out of water. A large majority of the city’s water supply comes from an underground aquifer that is being drained at a rate faster than it can refill. The ground is covered with concrete, which means that when it rains, rather than seep through the soil and return to the aquifer, the rainwater runs off. This collects pesticides and pollutants, which contaminate other water sources like rivers and lakes. Due to the quickly depleting aquifer, Mexico City is sinking downwards an estimated 1 meter every year[1].

Within the center of the Mexico City, the water scarcity issue has led to frequent water shut-offs. However, it is in the mountainous outskirts, that people are most vulnerable. In these areas, people are living off-grid and do not have access to water because there are no pipes from the city delivering water to people’s taps. Those that live in these regions rely on government supplied water trucks, known as las pipas, to bring them water. These trucks, however, are very unreliable, not coming for weeks at a time without notice. For this reason, many families in these regions are living off of 20 L of water per day per person. To put that in perspective, the average person in the US takes an 8-minute shower each day, which consumes about 65 L of water! You can imagine the strain that it puts on individuals to divide their 20 L ration for drinking, doing laundry, washing hands, dishwashing, and sanitation purposes. There often will not be enough water for sanitation and hygiene, which can lead to health concerns. Additionally, when the water trucks do not come, a burden is often placed on women and children to trek long distances to obtain water for their families. This prevents them from investing time in their careers and education.

In an attempt to address the water crisis, The Mexico City government has announced a rainwater catchment program for homeowners who live in parts of the capital with limited or non-existent water supply. Mayor Claudia Sheinbaum mentioned in a Twitter post that the government’s Environment Secretariat will install 10,000 rainwater harvesting systems this year in neighborhoods “with the biggest drinking water supply problems.” Isla Urbana is a non-profit organization that is playing a major role in this project by installing affordable and patented rainwater harvesting systems that are adaptable to the conditions of each house. They use a first flush system called a Tlaloque, which captures and discards the first few minutes of rain, which are the most polluted with air contaminants. The rest of the rain fall passes through a leaf-filter, a 50 micron filter to remove pests, and lastly a carbon filter before entering a cistern for storage. The cistern is equipped with a turbulence reducer, so that newly entering water doesn’t disturb any sediment that has settled to the bottom of the cistern, as well as chlorine to ensure that the water stays free of bacteria. A floating hose ensures that only water just below the surface, where it is cleanest, will be removed for use. These systems, installed in schools and homes, are able to provide families with 40%-100% of their annual water needs, depending on the size of the system installed. As a result, Isla Urbana rainwater harvesting systems also help mitigate city flooding and pollution problems since the water is collected and stored, hence preventing runoffs and pollution of local water resources.

Isla Urbana Summer Program students installed a rainwater harvesting system in the home of a woman named Rosa in Chiltepec.

Isla Urbana at Penn is the first student-run University chapter of this organization, based at the University of Pennsylvania in Philadelphia. Beyond fundraising during the year to support the efforts of Isla Urbana, each summer a group of motivated students arrive on site in Mexico City to work directly with its parent organization to help install rainwater harvesting systems for local schools and homes. During the summer of 2019, the University chapter was instrumental in installing a rainwater harvesting system in the house of a woman named Rosa, who is part of a mountain community in Quiltepec. Another member of the community named Elena narrated her story about her life before she had an Isla Urbana system installed in her home. She said that the government supplied water from las pipas (the water trucks), which only provided her with enough water for basic needs, such as drinking. She barely had enough for sanitation or washing clothes. As a result of the Isla Urbana system, Elena has become empowered to share sustainable practices within the community. Not only do many of the houses in the community now have rainwater harvesting systems, but they also have bio-digesters and they reuse their gray water. She hopes to build a community center where generations of people can gather to learn about sustainability.

On a global level, Isla Urbana is a replicable and a scalable model that can be implemented in countries suffering from water scarcity around the world. With the intent of working hand-in-hand with the community, policymakers and partnering NGOs, we can collectively come closer to solving the global water crisis.




Samira is a junior studying biochemistry in the Vagelos MLS program  at the University of Pennsylvania. She first became involved with Isla Urbana during her junior year of high school and has since then visited Mexico three times to install rainwater harvesting systems into rural communities.



Pallavi is a junior pursuing Biology and Healthcare Management through the Vagelos Program in Life Sciences and Management at the University of Pennsylvania. Having been raised in Bangalore, India, she has been involved in water conservation related efforts since high school. She co-founded the Isla Urbana student chapter at the University of Pennsylvania and has become very passionate about fundraising and installing rainwater harvesting systems to combat the water crisis in Mexico City.