Start Worrying About Your Tap Water

Trouble is the act has proved fairly easy to circumvent: It has been interpreted as applying to "navigable" waters. That reading would mean that polluters only face clear limits on dumping waste into waterways that allow ships, but as soon as a river gets too shallow, those constraints are ill-defined.
Waters of the U.S. would specify that the CWA extends to streams and wetlands that drain into larger bodies of water. It's a logical effort to control so-called externalities -- in this case, when the expense and harm caused by a polluter are borne by the public.