High concentrations of fecal bacteria, which are naturally found in both human and animal waste, may indicate a health risk to people who swim or wade in the creek—activities called “contact recreation” in the Texas Surface Water Quality Standards.

Yes, bacteria are naturally present in the Guadalupe River, as they are in all natural freshwater bodies. The primary concern for swimmers is typically E. coli, which serves as an indicator of fecal contamination from warm-blooded animals. While many strains are harmless, high levels can indicate the presence of pathogens that cause skin infections or gastrointestinal distress. In 2026, organizations like the Upper Guadalupe River Authority (UGRA) continue to monitor "swimability" at popular spots like Kerrville and New Braunfels. Bacteria levels frequently spike after heavy rainfall due to urban and agricultural runoff "washing" contaminants into the river. Conversely, during extreme droughts, low water flow can lead to stagnant conditions where bacteria become more concentrated. It is generally advised to avoid swimming if you have open wounds, to keep river water out of your nose and mouth, and to check local water quality reports—especially if the water appears unusually murky or discolored—to ensure the risk of illness remains low for your specific location.