Water Quality Standards are a critical element in protecting and improving water quality.  The federal Clean Water Act establishes a mechanism by which tribes can qualify to set water quality standards for lands under their jurisdiction.  The purpose of this guide is to examine those provisions (known as the TAS or treatment as states provisions) and the requirements that tribes must satisfy in order to exercise their sovereign right to promulgate water quality standards within the reservation.  The guidebook contains information about the specific requirements that warrant special attention or present important decisions that will need to be made as a tribe considers whether or not to apply for TAS status under the Clean Water Act.