StacksVerified U.S. regulatory reference

40 CFR §264.227

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (a)A surface impoundment must be removed from service in accordance with paragraph (b) of this section when:
    1. (1)The level of liquids in the impoundment suddenly drops and the drop is not known to be caused by changes in the flows into or out of the impoundment; or
    2. (2)The dike leaks.
  2. (b)When a surface impoundment must be removed from service as required by paragraph (a) of this section, the owner or operator must:
    1. (1)Immediately shut off the flow or stop the addition of wastes into the impoundment;
    2. (2)Immediately contain any surface leakage which has occurred or is occurring;
    3. (3)Immediately stop the leak;
    4. (4)Take any other necessary steps to stop or prevent catastrophic failure;
    5. (5)If a leak cannot be stopped by any other means, empty the impoundment; and
    6. (6)Notify the Regional Administrator of the problem in writing within seven days after detecting the problem.
  3. (c)As part of the contingency plan required in subpart D of this part, the owner or operator must specify a procedure for complying with the requirements of paragraph (b) of this section.
  4. (d)No surface impoundment that has been removed from service in accordance with the requirements of this section may be restored to service unless the portion of the impoundment which was failing is repaired and the following steps are taken:
    1. (1)If the impoundment was removed from service as the result of actual or imminent dike failure, the dike's structural integrity must be recertified in accordance with § 264.226(c).
    2. (2)If the impoundment was removed from service as the result of a sudden drop in the liquid level, then:
      1. (i)For any existing portion of the impoundment, a liner must be installed in compliance with § 264.221(a); and
      2. (ii)For any other portion of the impoundment, the repaired liner system must be certified by a qualified engineer as meeting the design specifications approved in the permit.
  5. (e)A surface impoundment that has been removed from service in accordance with the requirements of this section and that is not being repaired must be closed in accordance with the provisions of § 264.228.