This bachelor thesis focuses on the assessment of surface water quality and wastewater treatment plants in the Czech Republic. The thesis follows the current methodology and legislation. The first part contains a literature search dealing with water quality and wastewater treatment plants in general. Aspects of surface water are discussed, including the development and classification of its quality, pollutants, surface pollution and point source pollution, with an emphasis on wastewater treatment plants. This is followed by a practical part, which analyses the development of the number of wastewater treatment plants operated by ČEVAK a.s. - Operational Area North in the South Bohemian Region. The second half of the practical part focuses on the assessment of the quality of the streams on which the WWTPs are located, according to the ČSN 75 7221 standard.