Mexico City is in the midst of a water crisis. Some experts have predicted the metropolitan region, which boasts the highest population of any metro area in North America at nearly 22 million people, may start to run out of water as early as June, a day described as “Day Zero.” And while there are options available to the city, larger issues with water infrastructure and management may be harder to remedy in the short term.

At issue are the aquifers beneath the city, where most of the city’s water comes from. “When the Spaniards arrived on the continent, they drained the lakes on which the city was was built,” said Caroline Houck, senior editor at Vox. “And so all of the impervious surfaces that have been built on top of those don’t really allow for the rainwater that does fall to replenish the aquifers.” That infrastructure, along with moderate-to-severe drought conditions exacerbated by climate change, has drained the aquifers.

But Mexico City isn’t alone in it water struggles, as Houck reported in a story for the “Today, Explained” newsletter. She spoke with “Marketplace” host Amy Scott about the intersection of drought and water infrastructure, both in Mexico City and around the globe. The following is a transcript of their conversation.

Amy Scott: Caroline, can you describe the situation briefly in Mexico City? How did it get so bad?

Caroline Houck: Yeah, so Mexico City right now is staring down a pretty acute water crisis. There’s there’s a couple of acute factors here. There’s been abnormally low rainfall for a long time. And some of that is exacerbated by current phenomenon, things like El Niño, the weather phenomenon that’s causing droughts across the region. But in other ways is a much more structural, kind of systemic issue. When the Spaniards arrived on the continent, they drained the lakes on which the city was was built. And so all of the impervious surfaces that have been built on top of those don’t really allow for the rainwater that does fall to replenish the aquifers that provide actually the vast bulk of Mexico City’s water. And then there’s also some particular issues with the water infrastructure itself. Mexico City, by some estimates loses about 40% of its water that does enter its system, whether it’s through leaky pipes or being stolen. And then all of this is also being exacerbated by climate change, making these droughts worse and more unpredictable.

Scott: And you write that this isn’t just happening in Mexico City. Where else are people are facing water shortages right now?

Houck: I think that’s what really struck me when I got into this and why I was interested in this piece. I remember visiting Cape Town right around when they had their own Day Zero water crisis back in the 2010s. And to your point, it’s not just Mexico City right now. So right now, we have El Niño exacerbating droughts throughout Latin America. Bogotá, Colombia has been rationing water for a month now, I believe. Early on, the president, Gustavo Petro, even told people — I think semi-jokingly, I hope — to leave the city and drink water elsewhere, just because the system was so strapped. The Panama Canal, this lifeline of international commerce, is having to restrict transit through because drought has brought down the canal levels too low. I’m sure you’re familiar with the Colorado River in the U.S. [which] is over indexed and over allocated, and it’s causing issues across the American Southwest. So this is not the issue of one city. This is the issue of how we treat water in the 21st century.

Scott: You mentioned Cape Town, South Africa, which got dangerously close to Day Zero back in 2018. How did they end up surviving that crisis?

Houck: Yeah, so I think there’s a little bit of hope and there’s a little bit of pessimism here in that the idea of this Day Zero campaign really kind of launched a lot in South Africa during the time. It was launched as this kind of awareness campaign to get people to reduce consumption, and that awareness campaign helped extend the runway. But as an expert told my colleagues over on the “Today, Explained” podcast, what ultimately helped in South Africa is that it rained. And we can’t always count on the rain. So I think we need to make systemic changes, or at least that’s what the experts I spoke to said, that we need to really rethink how we manage water as a resource.

Scott: Yeah, I mean, Mexico City is also counting on rains coming, hopefully next month, but what other options does the city have?

Houck: Yeah, so I think there’s like the short term ones that maybe you’re already thinking of, from what I said previously. You can fix these leaky pipes. If you’re saving 40% of water, that’s a big difference if you’re counting the days down before there’s no water at all. But ultimately, what needs to happen is also rethinking not just the way we manage water, but also, some experts said, rethinking the way we grow our cities, making it more possible for the aquifers we all rely upon to replenish and to avoid these kinds of boom-bust cycles where you get an intense rainstorm and everything floods. And instead of it all percolating down and being there for the long term for the city residents. it just floods out and rushes out to the rivers and the sea.

Scott: When I’ve reported on water issues, I’ve heard over and over again, that water is too cheap. In other words, especially for the biggest users like agriculture, the price doesn’t reflect the actual cost of that water. And if if we had to pay that cost, maybe we’d do a better job of conserving as a society. Are you hearing that as well?

Houck: Yeah, so I actually had like kind of an interesting discussion in the different academics I spoke to about this. I’m personally still torn, I’m not going to endorse any side, but one one person told me about the good that’s being done by charging industry in American cities for their wastewater, their sewage, their runoff, and how that’s incentivizing them to think more creatively about, instead of just using water once through a system, can they can they reuse it multiple times? And that sounded really convincing to me. I’ve also talked to people who say, look, this is fundamentally a human right. And when we’re talking about water and urban environments, treating it as a commodity can lead to gross inequities. I’m not sure exactly what the answer is, but I think there is like a rich discussion there about the best ways to treat this.

Scott: Yeah. And one thing I’ve heard is is priced appropriately for people who can pay and subsidized for those who can’t.

Houck: So yeah, and I think that’s one of the things that really jumps out to me also about Mexico City right now is the way this is exacerbating inequality, right? Like there’s obvious tensions around who does get water, whose pipes regularly work, but also when they don’t work, who has the money to pay for that increasingly expensive use of water.