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The article presents general positions and features of a water quality assessment according to the norms of the European Union (EU), shows their difference from the national (Ukrainian) standards. It is proposed to improve the Ukrainian standards for assessing a water quality in accordance with the EU standards. On the example of the Danube and the Dniester rivers, a chronological variability of the water quality indicators is considered, the time trends of the indicators are approximated and the parameters of their distribution laws are determined. The following dependences are established: when approximating the distribution of the indicators it is better to use the lognormal law; an indicators time trend is reflected more accurately by the exponential dependence; a lognormal distribution of a trend-normalized indicator can be formally considered as one-parameter (one of the parameters -an average value of the logarithms of the normalized series -is zero). It is shown that for the previous period of time and in the future when normalizing the discharges of pollutants together with wastewater, a water quality assessment in the control points of the water bodies will meet the requirements of the EU standards on a frequency of exceeding the maximum permissible concentrations with the security which is equal to 5 or 10% depending on the purpose of the water body (5% -for fishery facilities, 10% -for drinking and recreational water use facilities).

The paper deals with the assessment of a surface water quality in the Kherson region, as well as the assessment of a technogenic load on the surface water bodies by the volumes of the wastewater and pollutants discharges over a long period of time. The problem of supplying the regions of Ukraine with water is urgent for many regions, including the Kherson region. The materials from the Regional reports, Ecological passports on monitoring a state the surface water as well as the data on the volumes of the sewage and pollutants discharges were used as baseline data. Water quality indicators was analyzed using the graphical method of a surface water quality complex assessment and method of estimation of surface water quality, based on hydrochemical parameters. Authors proposed to estimate a level of technogenic load on the surface water based on the calculation of the technogenic load module on the water objects (MWO). The purpose of the work was to assess a quality of the surface waters of the Kherson region as well as to assess a level of technogenic load on the surface water bodies of the region. It is obtained that a surface water quality of the region according to the fishery requirements in the most cases is characterized by classes IVa-IVd, category "very dirty", by drinking water-class II, category "polluted", class IIIa, category "dirty". There were significant exceedances of MPC according to fishery standards in terms of such substances as nitrites, Cr (VI), Cu and Ni. Maximum excesses were noted for Cr (VI) content. Also significant exceedances of the fisheries standards were observed in the content of sulfates, phosphates, Mn, BOC5, mineralization and others. In terms of economic and drinking requirements, the MPC was most often observed in such indicators as mineralization, BOC5 and Ni.With a general increase in water intake there is a decrease in the pollutants discharges. A level of technogenic load on the surface water bodies has significantly decreased. The obtained results are a part of a comprehensive study, which are devoted to the complex assessment of technogenic load on the surface water bodies of the Northwest Black Sea regions.