Groundwater litigation by environmental groups is increasing.  Both at the federal and the state level, increasingly sophisticated laboratory detection methods and other technological advances, as well as increasingly complex legal theories, are preesnting new challenges for industry, water purveyors and suppliers and governmental entities.  This presentation will include a discussion of the advances in technology, the changing landscape of legal theories and applications and offer some strategies both for asserting and defending these claims.  Particular emphasis will be placed upon litigation involving the federal Clean Water Act and Safe Drinking Water Act, but attention also will be devoted to novel legal frameworks such as California's Safe Drinking Water and Toxic Enforcement Act (Proposition 65).