Rainwater Harvesting Architecture Leads This Mexican Home
The Rain Harvest Home by Javier Sanchez of JSa architects and Robert Hutchison of Robert Hutchison Architecture in Mexico combines style and sustainability
About two hours west of Mexico City, in the Temascaltepec area, a recently completed home for an architect and his family is giving water conservation a new face. Comprised of three small structures including a main residence, an art studio, and a bathhouse, the Rain Harvest Home incorporates rainwater harvesting architecture – an uncommon practice despite the region having abundant rainfall.
Designed by home owner Javier Sanchez of JSa architects and Robert Hutchison of Robert Hutchison Architecture, the concept behind Rain Harvest Home is rooted in the unique qualities of its location – within Reserva el Peñón, a landscape-focused development that achieved water self-sufficiency for a community of 80 families in 450 acres of a nature reserve.
“In this reserve, each house is required to incorporate rain harvesting, with most of it coming from the individual house’s rainwater harvesting system and a small part coming from reservoirs on the reserve,” Sanchez explains. “We wanted to try and raise the bar and see if we could harvest 100% of our water from our individual site, rather than relying on external sources.”
Hutchison adds: “The reserve has really framed our thinking about sustainability in general and rainwater harvesting in particular. To a great extent, that pushed us to think on a much larger level, where the whole reserve became the site, and the house was a part of it. The house is 100% water self-sufficient and in times of surplus it is water positive and feeds the excess water back into the larger reservoir system in the community. Understanding that on-site water and power systems are part of a living process that fluctuates with changing natural conditions, the client continues to experiment with ways to optimize the system through seasonal calibrations and refinements. .
Each of the buildings has a system of aboveground and underground tanks that purify and store rainwater to supply the house throughout the year. The onsite water treatment system is primarily gravity fed and contains five cisterns that provide potable and treated water. A chemical-free blackwater treatment system also treats wastewater on site, allowing it to be reused as gray water for toilets or to water the orchard in the park, which together with the bio-agricultural gardens contributes to maintain a self-sustaining food system.
Creating a water-efficient home was of particular importance to Sanchez, who uses the residence as a place of retirement with his family. “We have a severe water shortage in Mexico City, which is absurd because it rains a lot, but we don’t harvest that rainwater. Instead, we pump water in and out of the valley. As designers, we need to talk about these issues in our designs and experiment with new possibilities. Sometimes when you have an example built, it’s easier to understand new possibilities, especially around rainwater harvesting.
He adds: “The project is an ongoing experiment, to see what is possible with rainwater harvesting in a closed loop system. Nothing is as objective as science suggests because things always change over time depending on the amount of rain and the timing. The house has to live with that, and it’s a constant learning experience for us as designers. It is about integrating design into the cycle of water and life.
Aesthetically, the buildings also articulate a symbiotic relationship with their natural surroundings. Each structure has a significant amount of covered outdoor space, blurring the line between indoors and out. The main residence is configured as a pavilion, with more than two-thirds of its footprint as outdoor space that can be used year-round. Rectangular in shape and largely horizontal, the main house is fitted with roof monitors to allow natural light to filter into all of its rooms.
“The site is relatively flat, but is in a mountainous environment. All around there are cliffs and steep slopes, but our site rests on a small vegetated plateau of continuous, single-storey shrubs and brush. Due to these site conditions, we wanted to see if we could make the buildings disappear into the vegetation. That’s why we designed a series of three low pavilions that nestle into the landscape and are scattered across the site,” says Sanchez.
“We wanted a strong link between each building and the landscape. Often as architects we think about how spaces are created between buildings, but it was about letting the landscape be that interstitial space. The landscape becomes the link between the buildings, just as it delimits the spaces between them. As you move around the site, it feels like the buildings are constantly disappearing and reappearing. It’s a process of discovery, where you don’t see it all at once.
This relationship becomes introspective in the public bath, which includes a hot tub, steam shower, sauna, and toilet that surrounds a cold plunge pool left uncovered.
“We liked the idea that each of the bathhouse’s four bathing spaces had no visual connection to the outdoors, but we wanted to bring the sun or moonlight down into these volumes through a skylight,” says Sanchez. “The light that descends into each of these spaces changes depending on the time of day.” §