How much does it cost to protect the environment and what are the benefits? These key questions have been the basis of STELLA's work for almost two decades. STELLA's unmatched experience in economic and financial analyses ranges from studying the feasibility of various options for water and waste management to assessing the costs and benefits of implementing EU environmental legislation. We have assessed tariffs for water and waste management services and assisted utilities in improving billing. We have estimated the financial and economic Net Present Value and Internal Rate of Return of a large number of infrastructure projects.