An individual or group must have "standing" to file a Clean Water Act lawsuit. This means they must have a connection to the adverse impacts that have been caused by a facility that is out of compliance with its permit or by the EPA not performing a mandatory duty. For example, you may need to prove that some of your members use or live on the stretch of river downstream from a permit violation or an unpermitted discharge.
To demonstrate standing in federal court, a person must show a “reasonable concern” over the environmental harm caused by the allegedly unlawful activity to a specific body of water which that person has reason to care about (i.e., uses or lives on) (Friends of the Earth, et al., v. Laidlaw Environmental Services Inc., 120 S.Ct. 693 (2000)).