Workload, cost, and time can all be significantly reduced through the use of sensitive field detectors that can screen samples and detect dilute concentrations of toxic contaminants. Such a sensor must be portable and cost effective, minimize sample handling, waste and need for reagents, have negligible false positives and negatives, and automatically provide unambiguous results to either field personnel or a central monitoring facility. In this paper, the suitability of Surface-Enhanced Raman Spectroscopy (SERS) as such a monitor will be discussed. The emphasis will be on the ability to rapidly (30 s) detect toxins, whether naturally occurring cyanotoxins or chemical warfare agents, in water supplies at ppb concentration levels. Includes 5 references, table, figures.