The article contains evaluation of functionality of sewage treatment plant in Jasło for multiplicity 2010 - 2014. On the basis of the results raw and cleaned sewage physico-chemical analysis, the efficiency of sewage treatment, coefficient of technological reliability, technological efficiency of sewage treatment and risk of the negative assessment of work of sewage treatment plant, were obtained, for following pollutions indicators: total suspended solids, BOD5, CODCr, total nitrogen and total phosphorus.Based on obtained results its conclude the average reduction of pollution on level below 90%. Only for total nitrogen the average reduction is lower and is on level 77%. Based on other values of indicators of reliability work of sewage treatment plant its conclude that the tested sewage treatment plant may be certified to operate in high quality and the sewage treated by this plant doesn't threaten the collector of the treated sewage. ...