Which statement correctly describes NPDES permit renewal submission timing?

• A. 90 days
• B. 180 days
• C. 240 days
• D. 120 days

Answer: (B)

The timing tested is the minimum lead time required to renew an NPDES permit. Renewal applications must be submitted at least 180 days before the current permit expires. This gives the permitting authority enough time to review the application, request any additional information, and complete any required steps (like public notice or negotiation) before the existing permit ends. Submitting earlier ensures continuity of coverage and reduces the risk of a lapse in authorization to discharge. Days like 90, 120, or 240 do not reflect the standard minimum interval, with 180 days being the correct guideline.