40 CFR § 147.2914 - Corrective action for wells authorized by rule.
Based on the Regional Administrator's discretion, corrective action to prevent movement of fluid into an USDW may be required for improperly sealed, completed or abandoned wells (i.e., wells or well bores which may provide and avenue for fluid migration into a USDW) within the zone of endangering influence (as defined in § 147.2904, Area of Review) of an injection well authorized by rule.
(iv)Plugging or replugging;
(3) A more stringent monitoring program; and/or
(b) If the monitoring discussed in paragraph (a) (3) or (4) of this section indicate the potential endangerment of an USDW, then action as described in paragraph (a) (1) or (2) of this section must be taken.