A unique water collection system, known as a chultún in Maya culture, has been discovered inside Building 25, also known as the House of the Halach Uinic, by researchers from the National Institute of Anthropology and History (INAH). This chultún, a design unique to the Mayan civilization, measures 2.48 meters in diameter and 2.39 meters in depth. The system's location inside a building, rather than outdoors, sets it apart from others found.

The discovery was made during the Archaeological Zones Improvement Program (Promeza), which is overseen by the Federal Culture Secretariat through the INAH. Unlike other chultúns, which were likely used to collect water, this one was roofed and contained human bone remains, suggesting it may have been used for rituals. This theory was proposed by José Antonio Reyes Solís, the coordinator of the Promeza Research Project in Tulum.

Enrique Marín Vázquez, the field supervisor and a member of the project, further explained that the chultún has a layer of ground coral, 1 to 2 centimeters thick, forming part of the surface soil. Beneath this layer, reddish clay was found. The structure also contained medium-sized stones, thick layers of pure ash, and at the deepest part, human bone remains and burnt stones. This suggests that continuous combustion processes took place before its construction.

The human remains are currently being investigated at the Physical Anthropology Laboratory of the INAH Quintana Roo. Preliminary findings suggest they could belong to three infants, who were buried with items such as deer antlers, shark teeth, and shell earrings.

While the architectural find will remain under protection and not open to the public for now, the INAH has announced plans to develop a virtual tour. This will allow the public to explore the inside of the structure in the near future.