This paper determines the evolution of the sanitation service provision at the level of 10 administrative-territorial units in Timis County during the period 2007-2017. In this respect we use the Data Envelopment Analysis methodology as a performant non-parametric method for determining efficiency. Subsequent to the general research goal, we demonstrate certain limitations of the methodology that can be remedied by an exhaustive mathematical approach. The results of the empirical analysis indicate small differences at the level of efficiency registered by the administrative-territorial units considered in the 11 years of the analysis and a lack of a trend to increase the efficiency level of the units. This work can be a guide for public decision-makers in the waste management area, for sanitation operators and attracts interest to citizens as users of the service.