The present work was developed in the city of Mérida, located on the Yucatán Península with 900,000 inhabitants approximately including its surrounding areas . All area is formed by a very permeable karst surface . Due to karstic conditions, there are a lot of fractures in the subsoil, the aquifer receives water from rainfall including any pollution that is picked up from the land surface [2,3]. The aquifer is also the unique source of water in the region. The main sources of pollution of the aquifer are the wastewater and sludge from the municipal wastewater system (septic tanks, small treatment plants and waste water from small industry).