Contaminated floodwaters and white foam spread in Naucalpan after heavy rains
The Verde River overflowed in Naucalpan, Mexico, on June 22, 2025, after intense rainfall, inundating streets with up to 1.5 m (5 feet) of water and spreading toxic foam.
Los Cuartos Dam after heavy rainfall on June 22, 2025. Credit: Ciudad Naucalpan
Intense rainfall caused the Verde River to overflow in Naucalpan, Mexico, on June 22, triggering urban flooding that affected at least 50 houses. The floodwaters also carried chemically contaminated foam into residential streets, raising environmental and health concerns.
The overflow occurred after rainwater exceeded the drainage capacity of local waterways and drainage systems.
Authorities reported that solid waste accumulation in channels such as the Verde and Hondo Rivers worsened the water flow and accumulation. Several neighborhoods, including San Rafael Chamapa and Nueva San Rafael Chamapa, experienced floodwaters ranging from 30 cm to 1.5 m (1 to 5 feet) in depth.
Flooded areas were covered in dense white foam, which was later identified as a mixture of domestic sewage, detergents, and industrial effluents.
Health authorities issued public warnings advising residents to avoid physical contact with the foam as it posed risks of skin irritation, chemical burns, and infectious disease. Field assessments confirmed the presence of irritants and high organic load, potentially hazardous for both human exposure and the environment.
The Federal National Water Commission (CONAGUA) reported that close to 700 tonnes of garbage were recently cleared from local drainage systems, but the infrastructure still couldn’t handle the runoff. Civil Protection units, the Mexican Army, and the National Guard were deployed to conduct cleanup operations and assist residents.
Local authorities denied that the Los Cuartos dam had overflowed, stating that its level remained controlled. They attributed the flooding solely to the river system, whose capacity was exceeded by excess water and debris accumulation.
No casualties have been reported so far as cleanup and health risk mitigation measures remain ongoing.
References:
1 El desbordamiento de una presa en Naucalpan provoca fuertes inundaciones – El Pais – June 23, 2025
2 Inundaciones por desborde de presa en Naucalpan causan contaminación – Digital News Qr – June 23, 2025
3 Se desborda presa Los Cuartos en Naucalpan; espuma residual cubre calles aledañas – El Economista – June 23, 2025
4 Gobierno de Naucalpan negó desbordamiento de la presa Los Cuartos en Naucalpan, Edomex – Infobae – June 23, 2025
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