Owners and operators must monitor tanks and underground piping for leaks in accordance with the requirements of this part. This section specifies general release detection requirements. WAC 173-360A-0610 and 173-360A-0615 identify allowed release detection methods for monitoring tanks and piping. WAC 173-360A-0620 through 173-360A-0675 specify requirements for each release detection method.

(1) Applicability. The following tanks and underground piping must be monitored for leaks in accordance with this part:

(a) Any portion of a tank that routinely contains regulated substances; and

(b) Any underground piping that routinely contains regulated substances. However, underground piping conveying regulated substances under suction does not need to be monitored for leaks if the piping is designed and constructed to meet the following standards:

(i) The below-grade piping operates at less than atmospheric pressure;

(ii) The below-grade piping is sloped so that the contents of the pipe will drain back into the storage tank if the suction is released;

(iii) Only one check valve is included in each suction line;

(iv) The check valve is located directly below and as close as practical to the suction pump; and

(v) A method is provided that allows compliance with (b)(i) through (iv) of this subsection to be readily determined.

(2) Closure of UST systems. Any UST system that cannot be monitored for leaks in accordance with the requirements of this part must be closed in accordance with Part 8 of this chapter.

(3) Release detection methods. Tanks and underground piping must be monitored for leaks using one of the applicable methods, or combination of methods, of release detection specified in WAC 173-360A-0610 and 173-360A-0615. Results from periodic release detection must be conclusive.

(4) Notification of changes in methods. Within thirty days after any change in release detection methods used, owners and operators must notify the department in writing.

(5) Performance standards for methods. Release detection methods must be able to meet:

(a) The performance standards specified for the method in this part, with any performance claims and their manner of determination described in writing by the manufacturer, vendor, or installer; and

(b) The compatibility requirements in WAC 173-360A-0350.

(6) Certification of methods or equipment. Except for inventory control (WAC 173-360A-0620) and weekly manual tank gauging (WAC 173-360A-0625), the methods or equipment used to perform release detection must be certified in writing by the manufacturer or vendor or an independent third party as capable of meeting the performance standards specified for the release detection method in this part using a test procedure:

(a) Developed by the U.S. Environmental Protection Agency;

(b) Developed by a nationally or internationally recognized association or independent testing laboratory; or

(c) Deemed equivalent by a nationally or internationally recognized association or independent testing laboratory to a test procedure developed by the U.S. Environmental Protection Agency.

(7) Performance of release detection. Release detection must be performed in accordance with:

(a) Any requirements specified for the method in this part;

(b) Any instructions specified by the equipment manufacturer; and

(c) Any conditions or limitations specified in the certifications required under subsection (6) of this section, if applicable.

(8) Suspected releases. When the results of release detection under this part indicate a release may have occurred, the suspected release must be reported and investigated in accordance with Part 7 of this chapter. The establishment of leak indication thresholds is a means of setting a standard for the equipment or method used. It is not intended to imply that actual leak rates or quantities less than the thresholds are allowable. No release is acceptable, and any indication that a release may have occurred should be reported and investigated in accordance with Part 7 of this chapter.

(9) Recordkeeping. Records of release detection must document compliance with this part, including the following:

(a) Any certifications of release detection methods or equipment required under this part. Certifications must be maintained for as long as the method or equipment is used;

(b) Any site evaluations required under WAC 173-360A-0660 or 173-360A-0665 for using vapor monitoring or groundwater monitoring as a release detection method. Site evaluations must be maintained for as long as the method is used; and

(c) The performance of release detection required under this part, including the results of all monitoring, testing, and sampling.

(i) For tank tightness testing (WAC 173-360A-0635), line tightness testing (WAC 173-360A-0650), and vapor monitoring using a tracer compound in accordance with WAC 173-360A-0610 (3)(d) or 173-360A-0615 (3)(b), at least the last two test results must be maintained.

(ii) For all other release detection methods, results must be maintained for at least three years.