For example, in 1988 it was found that Hays County was one of the top five counties in central Texas for leaking storage tanks placed underground. These tanks are thought to be one of the most substantial sources of the state's ground water contamination. This has obvious devastating effects to the salamander and other water species. Along with ground water contamination by storage tanks, there have also been numerous gas and oil spills. There are two railroad bridges and a major highway crossing the San Marcos River.
Any spills drain directly into the river.
The specific name nana , meaning dwarf, refers to the salamander's small size. Unlike most salamanders, the San Marcos Salamander never changes to become terrestrial. The San Marcos Salamander has very large eyes compared to its body size. Their eyes have a dark ring surrounding the lens. They have highly developed gills that are brightly colored.