40 CFR §63.1580

1. (a)You are subject to this subpart if the following are all true:
   1. (1)You own or operate a publicly owned treatment works (POTW) that includes an affected source (§ 63.1595);
   2. (2)The affected source is located at a Group 2 POTW which is a major source of HAP emissions, or at any Group 1 POTW regardless of whether or not it is a major source of HAP; and
   3. (3)Your POTW is required to develop and implement a pretreatment program as defined by 40 CFR 403.8, or your POTW meets the general criteria for development and implementation of a pretreatment program.
2. (b)If your existing POTW treatment plant is not located at a major source as of October 26, 1999, but thereafter becomes a major source for any reason other than reconstruction, then, for the purpose of this subpart, your POTW treatment plant would be considered an existing source.
3. (c)If you commence construction or reconstruction of your POTW treatment plant after December 1, 1998, then the requirements for a new POTW apply.