Urban wastewater management and the associated modelling has become indispensable today. Reliable calibration is essential for these models, and water level data is used as a standard. However, data collection can be limited due to high sensor costs and harsh conditions in the sewer. A novel solution is collecting data using low-cost temperature sensors, placing one in the stream, the other at the crest of the weir. In the case of dry weather, the sensor measures the air phase, whereas, in the case of Combined Sewer Overflow (CSO), the discharged storm and wastewater is measured. Autocalibration was performed using OSTRICH for a SWMM model in Berlin, with water level and fictional temperature data, and various number of measuring sites. Results showed that calibration using temperature data was as good as using water level data, with promising outcomes achieved by using one measuring site, offering a cost-effective alternative for water utilities.