Threats to cenotes and how to help
Cenotes are threatened by untreated sewage, pig-farm and crop chemicals, overcrowding, sunscreen and construction over caves. The Tren Maya railway drew strong criticism from cave divers and scientists for building over and into cave systems near Playa del Carmen and Tulum (reported).
Why cenotes are fragile
Cenotes are windows into the only freshwater source for millions of people on the Yucatán Peninsula. There are almost no rivers, the soil is thin and the limestone is full of holes, so anything spilled on the ground can reach the water fast and travel through connected caves for kilometres.
Main threats
- Wastewater: many towns and hotels rely on septic tanks or poorly treated sewage (reported), which seeps into the aquifer.
- Farm pollution: large pig farms in Yucatán state and crop chemicals add nitrates and pesticides (reported).
- Overtourism: crowds, sunscreen, lotions and stirred-up sediment.
- Construction over caves: roads, hotels and rail pillars on thin cave roofs.
- Rubbish dumping: some cenotes on private land were used as dumps.
- Saltwater rising: pumping too much fresh water and sea-level rise push saltwater inland.
The Tren Maya controversy
The Tren Maya railway (opened in stages from 2023) drew strong criticism for Section 5 between Playa del Carmen and Tulum. Cave divers and scientists reported steel pillars driven through cave roofs into flooded passages, and cement spilling into caves (reported). The government said damage was limited and that measures were taken. The debate is ongoing.
Who protects cenotes
- Mexico's INAH protects archaeological finds in cenotes.
- State environment agencies and some protected areas (for example the Ring of Cenotes state reserve in Yucatán, reported).
- Community-run (ejido) cenotes that depend on clean water for income.
- Groups such as cave-diving survey teams and local NGOs that map and monitor caves.
Restoration and community work
Projects in Yucatán have cleaned rubbish from cenotes and trained local communities to care for them, linking conservation with Maya culture and tourism income (reported).
How visitors can help
- Shower before swimming; skip sunscreen, lotion and bug spray.
- Never use soap or shampoo near a cenote.
- Don't touch formations or take stones, roots or artifacts.
- Stay on paths and inside roped areas.
- Choose community-run cenotes and eco-certified tours.
- Take all rubbish with you.
- Stay in hotels that treat their wastewater.
New to cenotes? Start with our main guide: what is a cenote. Ready to visit? See the best cenotes in Tulum.
Tren maya cenotes: frequently asked questions
What are the biggest threats to cenotes?
Sewage, farm chemicals, overtourism and construction over caves.
Did the Tren Maya damage cenotes?
Divers and environmental groups reported steel pillars driven into caves along Section 5, but the government disputed the scale.
Are cenotes protected by law?
Archaeological finds are, and some areas are protected, but the rules vary.
Why is sunscreen banned in cenotes?
It leaves a film on the water and adds chemicals to drinking water and to wildlife's home.
How can tourists help protect cenotes?
Shower first, skip lotions, follow the rules and support community-run cenotes.