The determination of disinfection byproducts (DBPs) has become extremely important to drinking water companies due to the newly imposed regulatory testing requirements by the EPA. The difficulty and expense involved in regulatory testing has necessitated the need for a low cost, simple, quantitative test for DBPs that can be done in real time. The new method, THM Plus, allows for the screening of chloroform, also called trichloromethane (TCM), dibromochloromethane (DCBM), bromodichloromethane (BDCM), tribromomethane (TBM), trichloroacetic acid (TCAA), dichlorobromoacetic acid (DBCAA), bromodichloroacetic acid (BDCAA), tribromoacetic acid (TBAA), chloral hydrate (CH), 1,1,1-trichloro-2-propanone (111-TCP), and 1,1,1-trichloroacetonitrile (TCAN). No extraction or concentration steps are required. No hazardous materials are used or generated in the proposed method. The new colorimetric method can be used to quickly adapt to changing influent water characteristics and to establish trending data for the information of DBPs throughout the distribution system. Multiple samples from across the United States were analyzed in comparison to the three EPA Methods for DBPs to validate the new method. Includes 4 references, tables, figures.