Distributed Temperature Sensing (DTS) along a fiber optic cable can be used to identify specific locations of significant I/I sources active during wet weather events. The Milwaukee Metropolitan Sewerage District (MMSD) Wauwatosa DTS study was performed in the summer of 2020 during several significant storm events. The MMSD study provided sufficient data for quantifying actual I/I discharges and proved the technology was capable of working successfully in warm I/I conditions. Analysis of the MMSD study data allowed for development of an estimation technique for localized I/I source inputs during the wet weather event, with the estimates calibrated to known flow rates at the downstream end of the measurement cable. A process was developed to locate-specific flow inputs during active events and results were compared across all three monitored events. A Return on Investment (ROI) estimate for DTS use is also provided.