A user shall have an affirmative defense to an enforcement action brought against it for noncompliance with the general requirements in § 50.015 or the specific prohibitions in § 50.016 if it can prove that it did not know, or have reason to know, that its discharge, alone or in conjunction with discharges from other sources, would cause pass through or interference and that either:
(A) A local limit exists for each pollutant discharged and the user was in compliance with each limit directly prior to, and during, the pass through or interference; or
(B) No local limit exists, but the discharge did not change substantially in nature or constituents from the user’s prior discharge when the city was regularly in compliance with its NPDES permit, and in the case of interference, was in compliance with applicable sludge use or disposal requirements.
(Ord. 02-09, passed 5-28-02)