Examples of violations that can be enforced by Section 505 citizen suits
Permit-related:
Lack of a permit when it is required
Discharges in excess of permit limits
Failure to monitor and/or report
General permit violations (e.g., not submitting Notice of Intent to be covered under the general permit, not meeting a requirement listed in the general permit)
Stormwater permit violations (e.g., not developing a stormwater management plan, not putting BMPs in place, not monitoring and inspecting as required)
EPA mandatory duty-related:
No action during required timeframe for review of or inappropriate approval of state-submitted water quality standards, 303(d) list or TMDL
No consultation with USFWS on approval of water quality standards or TMDL (filed under both ESA and CWA probably)