**1. Introduction**

Groundwater in Slovenia, as well as in many places across the globe, is the main source of drinking water. Apart from its use for drinking, it is often used for irrigation and other purposes. This makes groundwater valuable, and since it generally does not renew very quickly, it is often—as is the case in Slovenia—protected by national legislation. Quantity, however, is not the only issue we are facing in regards to groundwater. With the rapid increase in use of mineral nitrogen fertilizers and different agricultural as well as industrial chemicals in the past century, many of these substances found their way into groundwater. In last few decades—since the pollution was becoming more and more severe and even health threatening—a lot was done in terms of improving groundwater protection. Slovenia as an European Union member formed its legislation based on Water Framework Directive (WFD) and its recommendations. But despite that, groundwater status in some parts of the country is still not adequate, mostly because of the presence of nitrate. Main vulnerable areas are large alluvial plains—their flatness makes them very suitable for agricultural production, but their shallow soils make almost every activity on top of them affect the groundwater quality. The struggle is real, and on the following pages, we are about to uncover the theory and practice behind the groundwater protection in Slovenia.
