Balancing water treatment processes to adequately deal with the immediate threat from microbiological contaminants and the long term health effects of disinfection byproducts was the major challenge faced by the group of stakeholders who negotiated the second stage of the Disinfection Byproducts (DBP) rule and the LT2ESWTR. In order to take advantage of the vast amount of data collected as a part of the Information Collection Rule, the technical working group (TWG) supporting the stakeholders developed a computer program termed Surface Water Analytical Tool (SWAT). This program utilized the data available from the Information Collection Rule (ICR) database to determine the level of treatment process improvement necessary for each subjected plant to achieve the compliance criteria. Once this was done for all the subjected plants, the results were aggregated to determine the distribution of process improvements necessary (i.e. a compliance forecast) for a given compliance criteria. This computer program allowed the evaluation of the large water systems in the US and helped estimate the level of process improvement necessary for achieving compliance with various regulatory alternatives that were considered during the development of the proposed rule. In planning water treatment process improvements, engineers typically practice the concept used in the SWAT program. Use of this program as a planning tool allows a quantitative assessment (through the predictions made by the WTP simulation model) of the planning alternatives with respect to compliance with disinfection and DBPs. This paper gives a description of the tool and some examples of how this tool can be used in planning. Includes figures.