The tests were to specify the toxic effect on the basis of Vibrio fischeri luminescence inhibition caused by chemical compounds present in pool water samples. The testing tool was Microtox^®. This biotest produces quick results thus making it a comfortable tool for testing water for various toxicants. Furthermore, UV₂₅₄ absorbance measure was carried out and its value was a proxy parameter for defining participation of precursors to disinfection by-products in the samples. Some of the samples had high UV₂₅₄ values, one of them was 144 m^-1. The Microtox^® quality tests of indoor and outdoor swimming pool water presented in the paper proved impact of such factors like air exchange or supply of pool water circulation on water quality. Seasonal bathing waters had lower toxicity values. In the context of the work specifies that impurities in the water cause its toxicity. However, there was no relationship between high UV₂₅₄ absorbance values and higher toxicity of the samples. The toxicological analysis may serve as a screening test of swimming pool water quality. It is of key importance to check the free chlorine value for a water sample. High chlorine concentration can cause higher bioluminescence inhibition values.