Blog

Cenote Conservation

Threats, Sunscreen Bans & How We Help

The cenotes we dive today face unprecedented threats. Rapid development along the Riviera Maya, agricultural runoff, improper waste disposal, and mass tourism are contaminating these ancient water systems. Chemical sunscreens damage the delicate microorganisms that keep cenote water clean. At The Dive Machine, conservation isn't marketing — it's our mission through The Change Machine initiative.

Under Threat

The Crisis Facing Cenotes

The cenotes we dive today are not guaranteed to exist in their current state for the next generation. Rapid development along the Riviera Maya corridor, industrial agriculture, inadequate sewage treatment, and mass tourism are contaminating the underground aquifer that feeds every cenote on the Yucatan Peninsula. The water that was crystal-clear a decade ago is measurably degraded at several popular sites.

The problem is invisible from the surface. Because cenotes are connected to a vast underground river system, pollution from a construction site in Playa del Carmen can appear in a cenote 50 kilometers away. Pesticides from farmland seep into the aquifer. Untreated sewage from hotels percolates through the porous limestone. And the endemic species that evolved over millions of years in pristine conditions are now encountering chemicals their biology has no defense against.

Major Threats

What Is Killing Cenotes?

Urban Development

Construction of hotels, resorts, and housing developments disrupts natural water drainage patterns. Improperly sealed foundations leak directly into the aquifer. Deforestation removes the jungle canopy that regulates cenote water levels and temperature through shade and root systems.

Chemical Sunscreen

Oxybenzone and octinoxate — chemicals found in most commercial sunscreens — are toxic to the microorganisms that maintain cenote water quality. A single swimmer wearing chemical sunscreen introduces contaminants that persist for weeks. Biodegradable, reef-safe sunscreen is mandatory at all cenotes. Better yet: wear a rashguard.

Mass Tourism

Some cenotes receive hundreds of visitors daily. The cumulative impact of sunscreen, body products, urine, and physical contact with formations degrades water quality and damages structures that took thousands of years to form. Responsible operators like The Dive Machine limit group sizes to minimize impact.

Agricultural Runoff

Pesticides and fertilizers from farms seep into the aquifer and contaminate cenote water. Elevated nitrate levels — indicators of agricultural pollution — have been detected in cenotes across the peninsula. This feeds algae blooms that deplete oxygen and disrupt the natural ecosystem.

Sewage Contamination

Much of the Riviera Maya's sewage infrastructure is inadequate for the region's explosive population growth. Poorly maintained septic systems and illegal sewage discharge allow untreated waste to reach the aquifer. Coliform bacteria have been detected in cenotes near heavily developed areas.

Infrastructure Projects

Large-scale infrastructure developments near cenote zones risk disrupting underground water flow and potentially damaging cave structures. Environmental impact assessments do not always account for the fragile interconnected nature of the aquifer system.

Our Response

The Change Machine Initiative

What We Do

The Change Machine is The Dive Machine's conservation arm — not a marketing campaign, but a structured program with measurable impact. Our initiatives include:

  • Cleanup dives: Regular organized dives to remove trash and debris from cenotes and reefs
  • Environmental monitoring: Water quality testing at dive sites we operate
  • Sunscreen enforcement: Free biodegradable sunscreen provided to all clients
  • Small group policy: Maximum 4-6 divers per guide to minimize environmental impact
  • Community education: Programs with local schools about aquifer protection
  • Buoyancy training: Every diver receives cenote-specific buoyancy instruction

How You Can Help

Every diver who visits a cenote has the power to protect or damage it. Here is what you can do:

  • Use only biodegradable sunscreen — or better, wear a rashguard and skip sunscreen entirely
  • Perfect your buoyancy before entering cenotes — never touch formations, walls, or the bottom
  • Choose responsible operators who limit group sizes and enforce environmental protocols
  • Never remove anything — not shells, rocks, or archaeological material
  • Shower before swimming — body products and insect repellent contaminate cenote water
  • Spread awareness — share what you learned about cenote conservation with other travelers
The Future

What Is at Stake

The cenotes we dive today took millions of years to form. The formations inside them grew over tens of thousands of years. The species that inhabit them evolved over millions of years in pristine isolation. None of this can be recreated, replicated, or restored once lost.

If current pollution trends continue unchecked, scientists estimate that water quality in many popular cenotes could degrade to unswimmable levels within decades — not centuries. Elevated nitrate levels, chemical contamination, and bacterial counts are already measurably higher than they were 20 years ago at monitoring stations across the Riviera Maya.

This is not inevitable. Cenotes can be protected through proper wastewater treatment, regulated development, sustainable tourism practices, and community stewardship. The Maya managed these water sources for over 3,000 years without degrading them. Modern technology gives us even more tools — if we choose to use them.

At The Dive Machine, we believe that every diver who sees a cenote becomes an advocate for protecting it. When you experience the crystal-clear water, the ancient formations, and the unique life forms firsthand, you understand viscerally what is at stake. That is why we invest in conservation through The Change Machine — and why we encourage every diver to make choices that protect these irreplaceable ecosystems for future generations.

Ready?

Experience This With The Dive Machine

Our expert guides take you to the cenotes where you can experience this firsthand. Small groups, personalized attention, and 3,800+ five-star reviews.

Explore Cenote Diving Book Now
FAQ

Frequently Asked Questions

Chemical sunscreens contain oxybenzone and octinoxate which damage aquatic microorganisms and disrupt cenote ecosystems. Only biodegradable, reef-safe sunscreen is permitted. Better yet, wear a rash guard.

Many cenotes face contamination from development, agriculture, and tourism. While not officially "endangered," water quality has declined measurably in several popular cenotes over the past decade.

Use biodegradable sunscreen, maintain perfect buoyancy to avoid touching formations, never remove anything, choose responsible operators like The Dive Machine, and support conservation organizations.

The Change Machine is The Dive Machine's conservation initiative focused on cenote and ocean ecosystem protection. It includes cleanup dives, environmental education, and community partnerships.

Construction disrupts natural water flow, sewage systems can leak into underground rivers, and deforestation removes the jungle canopy that regulates cenote water levels and temperature.

Explore More

Best Cenotes for Diving

12 expert-picked cenotes ranked by difficulty, visibility, and unique features.

Bull Shark Diving

Seasonal encounters with bull sharks — and how we contribute to their conservation.

Diving Prices 2026

Transparent pricing for every dive experience. No hidden fees.

The Dive Machine Logo

The Dive Machine

SSI Instructor Training Center in Playa del Carmen, Mexico. Over 3,800 five-star reviews. Our team of 10+ certified SSI instructors specializes in cenote, reef, and bull shark diving since 2018. SSI certifications are internationally recognized — equivalent to PADI worldwide.