As the population increases, the need to satisfy demands such as food and housing increases every day, to such an extent that, in some cases, human settlements are located close to river basins; and, on the other hand, when farmers use this water to irrigate the crops they produce, they end up contaminating it. All this brings about that the quality of the water in the rivers is affected. In this sense, the main objective of the research is to evaluate the quality of water for irrigation of rice crops in the lower Portoviejo River basin using the ICA-NSF method, which is a statistical tool to estimate the quality of a body of water, for the establishment of strategies to prevent and control this problem, taking as references two points. The first, located in the El Frutillo community; the second, at the Higueron of Rocafuerte Bridge. The results obtained show that the water quality in the lower Portoviejo River basin, at point 1, is medium; and, at point 2, is bad. This, as a result of the increase of salinity in the water, which can significantly affect the optimal growth of the plants if the properties to which the roots are exposed get exceeded, in addition to excessive levels of phosphate and the concentration of high heavy metals such as Cobalt and Manganese, due to wastewater discharges, anthropogenic activities, mainly from agriculture and other polluting sources such as the lubricators and population near the meander of the river, which discharge directly into this flow without any type of control or at least awareness of the people who carry out these polluting activities. Finally, it is concluded that the water quality of the lower Portoviejo River basin, especially for crops and in this case rice, is not the most adequate; but it must be clear that, for farmers in this area, it is the only source of water supply for these types of productive activities.