EPA is promulgating final language revising the regulation that sets forth EPA's process for initiating the withdrawal of a State's primary enforcement responsibility (primacy) for the Public Water System Supervision Program under the Safe Drinking Water Act and making technical clarifying amendments to other parts of the primacy regulation. The revised language clarifies issues of EPA's timing and discretion in initiating the primacy withdrawal process and simplifies some of the rule language. The intended effects of these revisions are to eliminate confusion about the Agency's primacy withdrawal policy and to respond to a court ruling that requires a change to the regulatory language on withdrawals. These revisions reflect existing Agency policy and therefore should not impose any burden on States or otherwise affect EPA-State relations.