The aim of this study is to demonstrate the positive impact of ponds on water quality in a small stream Čermná. Four sites were sampled regularly every month for one year. Simultaneously, pH and temperature were measured continuously. The concentration of ammonia nitrogen, nitrate nitrogen and nitrite nitrogen were determined by subsequent analysis of the water samples. The results were classified in compliance with Government Decree (GD) No. 401/2015 Coll., as amended, and Czech standard ČSN 75 7221. High concentrations of ammonia nitrogen that were detected during the whole period are the result of the discharge of all wastewater from the village of Dolní Čermná to flow Čermná. Although the results showed a positive effect pond Čermenský, during the growing season the concentration of ammonia nitrogen at SP No. 2 placed under the pond increased mainly due to fertilizing pond by manure to increase nutrients for the fish population in the pond.