40 CFR § 265.444 - Inspections.
(a) During construction or installation, liners and cover systems (e.g., membranes, sheets, or coatings) must be inspected for uniformity, damage and imperfections (e.g., holes, cracks, thin spots, or foreign materials). Immediately after construction or installation, liners must be inspected and certified as meeting the requirements of § 265.443 by a qualified Professional Engineer. This certification must be maintained at the facility as part of the facility operating record. After installation, liners and covers must be inspected to ensure tight seams and joints and the absence of tears, punctures, or blisters.
(b) While a drip pad is in operation, it must be inspected weekly and after storms to detect evidence of any of the following:
(1) Deterioration, malfunctions or improper operation of run-on and run-off control systems;
(2) The presence of leakage in and proper functioning of leakage detection system.
(3) Deterioration or cracking of the drip pad surface.
See § 265.443(m) for remedial action required if deterioration or leakage is detected.