The purpose of the QTRACER2 is to serve as a technical guide to various groups who must address potential and/or existing contamination problems in hydrological systems. Tracing are always appropriate and probably necessary, but analyses can be difficult and tedious. This document and associated computer programs alleviate some of these problems. The Qtracer2 take basic input data obtained at the start and finish of a hydrologic tracer test and performs the basic calculations for extracting critical hydraulic and geometric information about the flow system under investigation. Tracer testing is generally regarded as the most reliable and efficient method of gathering surface and subsurface hydraulic information.