(1) Owners and operators of UST systems with spill and overfill prevention equipment and containment sumps used for interstitial monitoring of piping must meet the following requirements to ensure the equipment is operating properly and will prevent releases to the environment:

(a) containment sumps used for interstitial monitoring of piping and spill prevention equipment, such as a catchment basin, spill bucket, or other spill containment device, must prevent releases to the environment by meeting one of the following:

(i) the equipment is double walled and the integrity of both walls is periodically monitored at a frequency not less than the frequency of the walkthrough inspections described in ARM 17.56.307. Owners and operators must begin meeting (1)(a) and conduct a test within 30 days of discontinuing periodic monitoring of this equipment; or

(ii) the spill prevention equipment and containment sumps used for interstitial monitoring of piping are tested at least once every three years to ensure the equipment is liquid tight by using vacuum, pressure, or liquid testing in accordance with one of the following criteria:

(A) requirements developed by the manufacturer only if the manufacturer has developed requirements;

(B) code of practice developed by a nationally recognized association or independent testing laboratory; or

(C) requirements determined by the department to be no less protective of human health and the environment than the requirements listed in (1)(a)(ii)(A) and (B) or follow one of the department-approved methods listed below:

(I) hydrostatically test all containment sumps once every three years with liquid for one hour to a height six inches above the highest sump penetration. A passing test must show no liquid loss measured during the testing interval; or

(II) vacuum or pressure test containment sumps in accordance with the testing equipment manufacturer's instructions and pass/fail requirements.

(2) Testing conducted pursuant to (1) must be accomplished by a licensed installer or compliance inspector.

(3) Failed tests pursuant to (1) shall be reported to the department in accordance with ARM Title 17, chapter 56, subchapter 5.

(4) Overfill prevention equipment and containment sumps used for interstitial monitoring of piping must be inspected at least once every three years and meet the following:

(a) at a minimum, the inspection must ensure that overfill prevention equipment is set to activate at the correct level specified in ARM 17.56.201(1)(c) and will activate when regulated substance reaches that level; and

(b) inspections must be conducted in accordance with one of the criteria in (1).

(5) The code of practice from Petroleum Equipment Institute Publication RP1200, "Recommended Practices for the Testing and Verification of Spill, Overfill, Leak Detection and Secondary Containment Equipment at UST Facilities." may be used to comply with (1).

(6) Owners and operators must begin meeting these requirements for UST systems in use on or before October 13, 2018. The initial spill prevention equipment test, containment sump test, and overfill prevention equipment inspection must be conducted no later than October 13, 2021.

(7) For UST systems brought into use after October 13, 2018, these requirements apply at installation:

(a) owners and operators must maintain records in accordance with ARM 17.56.305 for spill prevention equipment, containment sumps used for interstitial monitoring of piping, and overfill prevention equipment;

(b) all records of testing or inspection must be maintained for three years; and

(c) for spill prevention equipment and containment sumps used for interstitial monitoring of piping not tested every three years, documentation showing that the prevention equipment is double walled and the integrity of both walls is periodically monitored must be maintained for as long as the equipment is periodically monitored.