Rainwater Harvesting Systems Transform Lives Amid Mexico's Water Scarcity

Walking up a steep hill to a small informal settlement of about 45 houses in Cristo Rey, above San Gregorio Atlapulco in Mexico City, Ana Aparicio Bahena arrives at her simple home. As she walks through her lush, verdant garden, she points out plants such as the prickly pear, cactus leaves with tiny, hair-like spines, and picks blackberries hanging from a bush, handing them to her two daughters.

“I can grow vegetables,” says Aparicio Bahena proudly, holding up a small onion. “I have avocados, lemons, potatoes … I never used to be able to grow my own food. It’s wonderful.”

Like many informal settlements across Mexico, Aparicio Bahena’s metal-roofed home is not connected to the water network, and for years she had to collect water from a well about 30 minutes away. With such water scarcity, gardening wasn’t a priority.

That was until a rainwater harvesting system, which captures water from the roof and filters it, was installed in her garden four years ago. It stores 2,500 litres of water, while a smaller tank, used only for watering plants, holds 1,100 litres.

The system is provided by Isla Urbana, an organisation dedicated to tackling water scarcity. It creates rainwater harvesting systems that provide mainly low-income households with sustainable water access for five to eight months of the year (during the dry season rainfall is insufficient). Founded in 2009, it aims to reach 1 million people who would previously have had to collect water themselves, by next year.

While most users are based in Mexico City, Jalisco and the State of Mexico, it has installed systems nationwide, mainly for Indigenous communities, who lack access to water due to geographic, economic or sociopolitical reasons.

“Much of our work involves delivering water to areas that are hard to reach with conventional systems,” says co-founder Enrique Lomnitz, who studied industrial design at university before deciding to develop sustainable solutions for low-income households.

The company operates as a non-profit when installing its systems for low-income families, while selling its systems privately to fund its work, alongside grants and donations from Mexico, the US and elsewhere. Many of its private contracts are with the government to supply water-scarce, low-income regions.

For governments, the system either replaces or complements fleets of water trucks, says Lomnitz. In the past three years, Isla Urbana has increased its focus on schools, installing rainwater harvesting systems at 2,000 public schools across the country, as well as educating children on water sustainability.

“The intention is to build the foundations for a much more water-conscious and water-capable population, with useful knowledge about how they could harvest and store water safely at home,” says Lomnitz.

While Mexico approved a national water access policy last year that outlines the human right to water and prioritises personal and domestic consumption over industrial use, water scarcity remains widespread. Droughts are a regular occurrence and have become more frequent and severe due to the climate crisis.

Almost 17% of households struggle to meet basic water needs such as drinking, cooking and handwashing, according to the National Health and Nutrition Survey, while 74 million people (57% of the population) lack access to safe water.

In the neighbourhood of Benito Juárez in Mexico City, Dora Napolitano relies on a 5,000-litre rainwater harvesting system in her garden to cope with scarcity. While Napolitano has access to tap water, unlike Aparicio Bahena, the textile artist says she bought the system in 2018 for environmental reasons.

“I was increasingly aware that the way we were living in Mexico City was completely unsustainable,” says Napolitano, who lives with her husband and four children, aged between 17 and 25. “Parents would complain about the traffic, the poor air quality, the flooding and the lack of water, but nobody took any responsibility. I’m not exonerating the government, but I felt the need to discover how much I could do.”

Napolitano says the system, which cost about 40,000 Mexican pesos (£1,700), including installation, has been “a life-saver” during intense periods of drought, such as in 2018 and two years ago, when there was no mains water for several weeks.

“It has got us out of trouble several times,” she says. “We live in a privileged area of Mexico City, but if we lived somewhere without [tap] water, we would be using it a lot more. I really wanted to show that it was viable.”

Judith Domínguez, a research professor specialising in water management, the climate crisis and urban environment at El Colegio de México, says rainwater harvesting is a good alternative in areas lacking formal public services.

“These systems can mitigate water scarcity, especially during rainy seasons, as well as address social and water vulnerability,” she says. “They require minimal maintenance, are installed at the household level, and can purify the water on-site for various uses, including drinking.”

Yet the systems must be constantly monitored to ensure water quality is maintained to prevent health problems, says Domínguez.

“This also involves technical issues such as filter inspection and replacement, which the household must do itself once government or non-governmental organisation assistance is withdrawn,” she says. “The household bears the cost. Mechanisms must be found to make it more affordable than constantly buying bottled water or water delivered by tanker trucks from private vendors.”

Back in Cristo Rey, for Aparicio Bahena, the rainwater has not only enabled her to grow food but is also used for washing clothes, flushing toilets and cleaning, allowing the six-person household to bathe regularly. “We used to only be able to wash once a week,” she says.

While the harvested water is not drinkable, Aparicio Bahena uses a small plastic filter to convert this greywater into safe drinking water. For her, water is no longer a source of stress, adding to the two-hour journey she faces every day to get to work as a maid.

“The water harvesting system really changed our lives. Now we are able to dream and have more time,” she says. “It changed everything.”