Waters co-produced during petroleum extraction are normally considered wastes but are also possible resources, especially in water-stressed regions. Produced waters can be chemically complex. High salinity, naturally occurring radioactive materials, and organic substances derived from the producing formation can complicate treatment processes. Rapid screening methods to characterize produced waters could be important in determining effective and efficient treatment strategies, as the composition of these produced waters can vary dramatically. In this study, excitation-emission matrix spectroscopy (EEMs) was used to assess the types of fluorescent dissolved organic matter (fDOM) present in produced waters from six unconventional petroleum plays in the United States. EEMs is a fast analysis that requires little to no sample preparation and can be done on-site of oil and gas operations, making it an ideal field screening tool. Eighteen produced water samples were analyzed using EEMs, absorption spectroscopy, and non-purgeable dissolved organic carbon analysis.