This paper is designed to show environmental engineering students the importance of developing scientific skills in unit conversions. These topics are discussed in the first semester of Physics. Although this topic is relatively easy to learn, traditionally it is only focused on the classical procedure of multiplying a given value by the indicated conversion factor. This way of solving these exercises tends to mechanize the students since it is customary to use a simple recipe to perform a linear, area or volumetric conversion. In this problem set, a series of exercises have been designed to work on unit conversions in a different way from the traditional one, i.e., they are problems in context applied to environmental engineering. All the exercises require a certain logical analysis to then propose a solution strategy and, finally, to clearly answer the questions indicated in it.