R18-11-120. Enforcement of Non-permitted Discharges

A. The Department may establish a numeric water quality standard at a concentration that is below the practical quantitation limit. Therefore, in enforcement actions pursuant to subsection (B), the water quality standard is enforceable at the practical quantitation limit. B. Except for chronic aquatic and wildlife criteria, for non-permitted discharge violations, the Department shall determine compliance with numeric water quality standard criteria from the analytical result of a single sample, unless additional samples are required under this article. For chronic aquatic and wildlife criteria, compliance for non-permitted discharge violations shall be determined from the geometric mean of the analytical results of the last four samples taken at least 24 hours apart. For the purposes of this Section, a “non-permitted discharge violation” does not include a discharge regulated under an AZPDES permit.