Hierve el Agua, Oaxaca’s Calcified Mineral Waterfalls

During my initial few months in Oaxaca, I had the comfort of time to explore the area at leisure. There were street food crawls and market wanders, cooking classes and long coffees with locals and expats to learn more about the city I decided to call home.

In the middle of these exploratory days was a jam-packed week when my mother planned a last-minute visit to town. We ate, we hugged, we drank a lot of mezcal, and we spent a whirlwind day of sightseeing. I took her to the archeological ruins at Mitla, to the widest tree in the world, El Tule, and to Hierve el Agua.

I hope to write about Mitla and the Tule tree another time, as both are fascinating in their own right. In the interim, I wanted to share a short post about Hierve el Agua, the calcified waterfalls roughly 70km (40-45 miles) South-east of the city Oaxaca de Juarez. Not only are they a gorgeous sight, but the history and geology make for interesting learning. Also, the oxymoron of the sight’s name merited a discussion on the blog.

Why are Oaxaca’s falls called Hierve El Agua?

Initially, I was confused looking at these waterfalls because in Spanish, hierve means to boil. I expected boiling water over the side of a mountain, an endless loop. Instead, Hierve el Agua looked frozen in time, cascading down the side of a cliff to the valley below.

After my visit, I learned that Hierve el Agua was created by mineral water that pushed through karstic limestone, depositing the falls onto the mountain’s edge. While the waterfalls are white, two mineral pools sit at the edge of the cliff, full of calcium carbonate, magnesium, and just enough sulphur to lend them a yellow hue.

Per the Merriam Webster Dictionary, the Greek word stalaktos means “to drip”. In the case of underground caves, rainwater trickles down, seeping through limestone and creating a calcite patch on the roof. In the case of Hierve el Agua, the process happened outside, with minerals that bubbled out from the middle of rocks, slowly calcifying over thousands of years into the rock formations that you see today. These ‘falls’ were named for the subtle phenomenon of mineral deposits “boiling” on the mountainside.

The name is slightly misleading because the springs aren’t actually boiling. They are heavily carbonated instead, with temperatures varying between 22-26C. To be fair they do spurt out from the rocks like boiling water might. And their nonthermal temperatures mean that swimming is a possibility. Yay!

A Brief History of Hierve el Agua Waterfalls

Hierve el Agua might be a tourist destination today, but the bubbling springs used to supply water to an intricate series of canals and terraces leading down to the valley, comprising one of the most complete terraced irrigation sites in Mesoamerica. An intricate network of canals and terraces carried mineral-rich water down the mountainside to agricultural fields in the valley below, allowing the Zapotec people to farm in an otherwise dry highland landscape. The work of James A Neely, including his paper entitled “Irrigated Agriculture at Hierve el Agua, Oaxaca, Mexico“, documents this system in detail, estimating that it was in active use for several centuries before being abandoned around 1300 CE.

What makes Hierve el Agua’s irrigation works particularly impressive is their completeness: unlike many pre-Columbian agricultural sites, enough of the canal and terrace infrastructure survives to give archaeologists a relatively clear picture of how the system functioned. Neely’s work suggests the Zapotecs engineered the canals to exploit the natural carbonate-rich springs, using the same mineral-heavy water that created the petrified falls to nourish their crops. Walking the trail today, you can still spot remnants of those terraces carved into the hillside.

Presently there are two falls to visit, a larger (called cascada grande, that sits approximately 9 stories (or 98 feet) high, and a smaller one (called, you know it, cascada chica at 4 stories (or 39 feet) high), which we visited at the same time. From the top of the mineral pools we hiked a short few minutes up, then looped around to the left to view the second, smaller fall from the other side of the rock’s edge.

We arrived early and I would suggest you do also, as the site gets awfully crowded during high season. There are changing rooms not far from the parking lot if you need to change into a swimsuit to take a dip in the mineral pools and cool off.

And because it’s me, I’d be remiss if I did not mention the food: there are stalls serve the usual corn snacks, perfect for the next leg of your journey: quesadillas, memelas, and more. We got ours filled with stringy quesillo, Oaxacan cheese, and squash blossoms. Also recommended for a snack: freshly chopped jicama, a delicious Mexican turnip that is faintly sweet and extremely refreshing, especially when dipped into a combo of chili, lime, and salt.

Responsible Tourism is a Must when Hiking and Visiting, Anywhere!

As with any beautiful natural wonder, it’s important to be responsible in your visit. This means no activities that could damage the land, not straying off the walking paths, and of course not leaving a trace. There is a moderately challenging loop trail near San Lorenzo Albarradas with paid parking at the entrance. It’s approximately 2.6km (1.7 miles) long, and should not be deviated from in order to protect the surrounding flora and fauna. It is worth noting that recent trail reviews mention that hikers should not complete the full loop alone due to snakes and the risk of getting lost.

In 2019, two tour companies were singled out by Hierve’s municipality San Isidro Roaguía for not following laws and customs at the site (link is Spanish), and the site is far busier and Instagram-popular than it was when we visited.

For more information about how to travel responsibly, please see these 20 tips from Uncornered Market.

Sustainability concerns remain for Hierve El Agua

Oaxaca has become a more and more popular place to visit, with a focus on the textile, food, and mezcal of the region. As more tourists poured into the Oaxaca Valley, Hierve el Agua became more and more crowded as well. According to a Conde Nast Traveler article about the closure, the president of the land affairs committee in the San Lorenzo Albarradas municipality where Hierve el Agua is located said that the falls drew anywhere from 2,500 people to 7,000 people per day pre-pandemic.

Despite these soaring numbers of tourists, the local area, predominantly inhabited by Zapotec people, has remained mired in poverty. Community landowners in San Lorenzo Albarradas have maintained that the Oaxaca government did not transfer millions of pesos it was owed from entry fees to Hierve el Agua, and that state management of the falls did not make room for sustainable tourism plans.

When and How to Visit to Hierve El Agua

• Best time to visit: The dry season from November to April is the best time to visit, with warm, sunny weather and less chance of rain.
• Camping: Camping at the site is now possible for 100 pesos per person, which is a lovely option for photographers or those who want to beat the early crowds
• Accessibility note: The terrain is uneven and the trails are not paved. For wheelchair users, or those who are less mobile, it may only be possible to see the falls from slightly farther away.
• Getting there: (1) the simplest is to hire a driver, and combine Hierve with other sights in the region, such as Mitla and the gorgeous El Tule Tree, the widest tree in the world. If you would like to use a driver, I have a trustworthy recommendation for you — just send me an email via the contact form on the site. There are (2) some tours that are specific to Hierve el Agua, but I have not used them other than Suzanne Barbezat’s Discover Oaxaca tours, which I can recommend. She does private tours to Hierve el Agua and elsewhere in the Oaxaca Valley. The cheapest would be to (3) take a bus or collectivo (shared taxi) from Oaxaca City just outside the baseball stadium (north of the city center) to Mitla. From there, you can grab another shared taxi or shared pickup truck to Hierve el Agua; you’ll see them holding signs for your destination.
• A note about tolls: Note that there is now highway leading from Oaxaca to Hierve el Agua, and there is a toll of 50 pesos to take that new road. In addition, the pueblo of San Lorenzo Albarradas has put up what they refer to as road maintenance toll on the way to Hierve, which is an additional 10 pesos per person. Finally, there is an ejido (community property toll) charged about 2 miles before the main entrance, reported at around 50 pesos per person.
• Entrance fees and parking: Entrance to the springs are paid separately, at 50 pesos per person. And finally, if you do hire a driver, the parking at Hierve el Agua is 80 pesos per car.

More about Hierve el Agua from Visit Mexico’s official site here.