Publicly owned treatment works
Publicly owned treatment works or POTW means any device or system used in the treatment (including recycling and reclamation) of municipal sewage or industrial wastes of a liquid nature which is owned by a State or municipality (as defined by section 502 of the CWA). This definition includes sewers, pipes, or other conveyances only if they convey wastewater to a POTW providing treatment.
40 CFR § 260.10
When used in parts 260 through 273 of this chapter, the following terms have the meanings given below: