The lack of water in the future will force society to find more sophisticated solutions for treatment and improvement of groundwater wherever it comes from. Contamination of soil and groundwater is a legacy of modern society, prevention of contaminants spread and secondary water reuse options shall be considered. The aim of the book chapter is to give oversight view on problems and challenges linked to groundwater quality in Eastern Baltic region whilst through case studies explaining the practical problems with groundwater monitoring, remediation and overall environmental quality analysis. The reader will get introduced with case studies in industry levels as credibility of scientific fundamentals is higher when practical solutions are shown. Eastern Baltic countries experience cover contamination problems that are mainly of historic origin due to former Soviet military and industrial policy implementation through decades. Short summaries for each case study are given and main conclusions provided in form of recommendations at the very end of the chapter.