One of the challenges the seawater desalination industry faces today is reverse osmosis (RO) membrane biofouling. Traditional water quality parameters such as SDI and the RO feed water turbidity are inadequate at protecting the membrane from biofouling. This research investigated the environmental and water quality parameters in a Southern California desalination plant in order to develop a set of seawater desalination RO membrane biofouling indicators. Statistical analysis was performed on data collected onsite over two years. The relationships between operation parameters, rain precipitations, TOC, UV254, chlorophyll fluorescence in raw seawater and the performance loss of the RO desalination process are presented. The environmental triggers for accelerated RO membrane biofouling was further investigated by developing membrane fouling simulators at the desalination pilot plant. Biofouling was confirmed by confocal laser scanning microscopy investigation of membrane biofilm and live and dead bacterial cell counts. The results of this study indicated that biofouling was significantly correlated with water quality changes. Thus, chlorophyll fluorescence measurements can be used as a precursor for desalination membrane biofouling. (C) 2013 Elsevier B.V. All rights reserved.