Inexpensive geophysical instruments can help meet a need for cost-effective siting of water wells in developing nations. We have developed resistivity, induced polarization, and seismic-refraction instruments that are useful in shallow hydrogeology studies. In addition, our free software can be used to interpret the data recorded by the instruments and produce predictions of subsurface lithologies. This entire suite of geophysical instruments, including a laptop computer for analysis and reports, can be assembled for less than US$600. It is hoped that trained indigenous well drillers and aid workers will use these instruments in support of their efforts to provide water to rural regions of the world that lack safe water.