The aim of the study is to determine the fractional share of organic pollutants in washings samples, collected after pressure filters washing. The evaluation of the physicochemical and toxicological quality of raw washings, fraction <200 kDa, <30 kDa and <300 Da has been presented. Separation of selected fractions was carried out with the participation of a multistage pressure membrane system using ultra- and nanofiltration. The physicochemical analysis was conducted based on the total organic carbon (TOC) concentration, dissolved organic carbon, and total carbon. The toxicological classification of isolated fractions was also prepared using the percentage of toxicity effects obtained in commercial bioassays—Microtox^® and Artoxkit M. The concentration of TOC in the analyzed samples of raw washings was ranged from 2.50 to 11.00 mgC / L. The presented study showed a significant share of the organic pollutants fraction with a molar weight below 300 Da in the examined washings (the TOC was from 0.71 to 1.48 mgC/L). No correlation was observed between the concentration of TOC and the percentage of toxic effect. Screening toxicity tests can be a signal of swimming pool water quality; but they need to be extended with additional test organisms or observations of more morphological parameters of these organisms.