California Code of Regulations › Title 23 - Waters › Division 3 - State Water Resources Control Board and Regional Water Quality Control Boards › Chapter 16 - Underground Tank Regulations › Article 4 - Existing Underground Storage Tank Monitoring Requirements › Section 2643 - Non-Visual Monitoring/Quantitative Release Detection Methods

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
(a)
				  Non-visual quantitative release detection methods shall comply with the
				  requirements of this section. Subdivision (b) contains monitoring requirements
				  for underground storage tanks; subdivision (c) for pressurized piping;
				  subdivision (d) for suction piping; and subdivision (e) for gravity-flow
				  piping. Examples of release detection methods that may be used to meet the
				  requirements of this section are in Appendix III.
(b) Quantitative release detection methods
				  used to monitor underground storage tanks shall be conducted according to one
				  of the methods listed in paragraphs (1) through (4) below. These quantitative
				  monitoring methods shall meet the requirements of section
				  2643(f) and shall
				  be capable of detecting release rates specified in this section with at least a
				  95 percent probability of detection and not more than a five percent
				  probability of false alarm.
(1) Automatic
				  tank gauge --
The automatic tank gauge shall test the tank at least once
					 every 30 days after product delivery or when the tank is filled to within 10
					 percent of the highest operating level during the previous 30 days and shall be
					 capable of detecting a release of 0.2 gallons per hour. The automatic tank
					 gauge shall generate a hard copy of all data reported including time and date,
					 tank identification, fuel depth, water depth, temperature, liquid volume, and
					 the duration of the test. Automatic tank gauge systems installed on or after
					 January 1, 1995, shall also generate a hard copy of the calculated leak rate
					 and leak threshold.
(2)
				  Statistical inventory reconciliation plus tank integrity testing --
Statistical inventory reconciliation shall be conducted at
					 least once every 30 days in accordance with section
					 2646.1 and shall be capable of
					 detecting a release of 0.2 gallons per hour. In addition, a tank integrity test
					 shall be conducted at least once every 24 months in accordance with section
					 2643.1. On and after October 1,
					 2018, statistical inventory reconciliation shall report a quantitative leak
					 rate using a threshold value that does not exceed one-half the minimum
					 detectible leak rate at least once every 30 days.
(3) Continuous in-tank leak detection --
On and after October 1, 2018, continuous in-tank leak
					 detection shall be capable of detecting an unauthorized release of 0.2 gallons
					 per hour. Continuous in-tank leak detection shall operate on an uninterrupted
					 basis or within a process that allows the system to gather incremental
					 measurements to determine the leak status of the tank at least once every 30
					 days.
(4) Other test methods
				  --
Other equivalent test methods may be used following review
					 by the State Water Board for compliance with this subdivision and subdivision
					 (f) below.