Principal river systems include the Santa María, the Ayutla River and the Jalpan River with their tributaries such as the Concá River in the south of the municipality. The Santa María enters the municipality from San Luis Potosí and flows along a 400 meter deep canyon until it merges with the Ayutla River. This river flows northeast, forming another canyon then merges with the Jalpan River. There are about 100 accessible sources of water in the municipality with most located in the communities of Salitrillo, Concá and Ayutla. The municipality is home to the junction of two of the major rivers of the Sierra Gorda, the Santa María and the Ayutla River at a location called Las Adjuntas. The Santa María River here flows warm to hot in the summer and the Ayutla River remains cold. Although the two rivers have different water colors and temperatures, both are regulated by the surrounding environment. The Santa María River has a number of beaches which are open to camping. There is also sports fishing of native catfish. The northern border of the municipality is partially formed by the Verde River. The Concá Waterfall is located just south of the town of the same name. This waterfall is fed by a fresh water spring and falls into the Santa María River. Despite the name (which means dry stream or dry arroyo), most of the arroyos in the area have water in them most of the year. The municipality has ten easily accessible sources of surface water. However, the over extraction of water has led to dropping water tables and many of the area's fresh water springs are flowing at slower rates or have dried up.