Designed to be a guide for community action, this booklet examines issues and trends related to groundwater contamination. Basic concepts about groundwater and information about problems affecting it are covered under the categories of (1) what is groundwater? (2) availability and depletion; (3) quality and contamination; (4) public health considerations; (5) detection and monitoring; (6) federal legislation; (7) state and local legislation; (8) descriptions of three state programs; (9) community organizing efforts (including three examples); and (10) recommendations for citizen action. Appendices deal with how to have your water tested, additional information on legislation, suggested lists, and citizen organizations and contacts in most states. The booklet is one in the series of community action guides developed by Concern, Inc. (TW).