Primary sources of inflow and infiltration (I&I) include leaky manholes, lateral connections and sewer mains–yet too often rehabilitation efforts target assets indiscriminately. And while I&I can account for up to 45% of the throughput at a treatment plant, an analysis-driven strategy to address I&I is seldom discussed. If municipalities identify I&I problem areas, they can address the defects found in a comprehensive manner—adding to their success rate. By implementing a total system approach of inspecting for sources of I&I and then planning rehabilitation efforts accordingly, municipalities can achieve approximately a 50% reduction of I&I. The white paper, Working Smarter Against I&I, lays out tools and strategies available to wastewater systems to address inflow and infiltration. With the concepts presented in this paper, not only will you understand how to assess the condition of your sewer system, you’ll be prepared to cut I&I by up to half.