Lomnitz is the director of Isla Urbana, a local environmental group that is pushing what it says is a simple solution to at least part of Mexico City’s water crisis — rainwater harvesting. Lomnitz says, “As the water situation gets worse and worse, our proposal gets stronger and stronger.” He explains that rainwater harvesting is a natural fit in Mexico City, since over a million homes already have tanks, or cisterns, for storing water from either the intermittent city water system or delivery trucks.
Lomnitz says water from the rainy season in the summer and fall can supply a household for up to six months. And with tanks already in place, he says Isla Urbana’s system is quick and easy to install. All that is required are some new gutters to channel the rainwater, new plumbing to draw off the first flush of water in a rainstorm, which is often contaminated with air pollutants, and a couple of special filters. The total cost is no more than six hundred bucks per household.