The San Juan Bay Estuary Program conducts weekly monitoring of bacteriological levels at selected beaches and lagoons along the northeastern coastline of the island. The purpose is to regularly assess water quality and keep the public informed about the water quality in areas frequented by the public. The map below shows the sampling locations along with their respective enterococci levels. According to the Puerto Rico Environmental Quality Board (PQB), enterococci concentration is an indicator of the potential presence of pathogens in the water, which could cause disease in warm-blooded animals (2018). The enterococci parameter follows the threshold established by the U.S. Environmental Protection Agency, known as the "Beach Action Value," which allows the public to be informed about water quality in each sampled area. According to this parameter, if enterococci levels exceed 70 CFU/100 L, the area is not suitable for swimming or recreational activities requiring direct contact with the water. The most common causes of increased enterococci levels, according to the JCA, are the runoff of contaminants, illegal discharges into the storm sewer system, areas without adequate wastewater management systems, and poor septic tank maintenance. Additionally, increased enterococci levels have been identified during heavy rainfall events, as runoff reaches bodies of water such as beaches and lagoons. It is recommended to avoid contact with the water for twenty-four (24) hours after the rainfall event has ended.
- Four (4) sampled areas are unsuitable for swimming, of which two (2) are lagoons and two (2) are beaches. The areas found to be unsuitable for swimming are located in the following places: San Gerónimo (112 colones/100 L), Aguadilla Street (84 colones/100 L), Serra Street (201 colones/100 L), and Cervantes Street (98 colones/100 L). The watershed comprises seven (7) municipalities, but these four (4) locations are within the municipality of San Juan.
- In the case of the sample taken on Naim Street (63 col/100 L), the results were close to the threshold of the “Beach Action Value” that has been established by the Environmental Protection Agency (EPA).
