NaClO, Ca(ClO)(2), ClO2, as well as Cl-2 doses followed by UV irradn. were used sep. to disinfect water in swimming pools. The concn. of free CI in pool water changed in the range 0.36-0.74 mg/L The contents of nitrates and chlorides in pool waters were measured and compared with their contents in the water used for topping up. The oxidn. resulted in significant increase in the content of nitrates and chlorides in pool waters.