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(continued)
(1) An independent third party testing laboratory shall evaluate and approve the method using the appropriate "EPA Standard Test Procedure" for leak detection equipment in Appendix IV; or,
(2) An independent third party testing laboratory shall evaluate and approve the method using a voluntary consensus standard that is intended for the method being evaluated; or,
(3) An independent third party testing laboratory shall evaluate and approve the method using a procedure deemed equivalent to an EPA procedure. Any resultant certification shall include a statement by the association or laboratory that the conditions under which the test was conducted were at least as rigorous as those used in the EPA standard test procedure. This certification shall include statements that:
(A) The method was tested under various conditions that simulate interferences likely to be encountered in actual field conditions (no fewer nor less rigorous than the environmental conditions used in the corresponding EPA test procedure);
(B) Each condition under which the method was tested was varied over a range expected to be encountered in 75 percent of the normal test cases;
(C) All portions of the equipment or method evaluated received the same evaluation;

(D) The amount of data collected and the statistical analysis are at least as extensive and rigorous as the data collected and statistical analysis used in the corresponding EPA test procedure and are sufficient to draw reasonable conclusions about the equipment or method being evaluated;
(E) The full-sized version of the leak detection equipment was physically tested; and
(F) The experimental conditions under which the evaluation was performed and the conditions under which the method was recommended for use have been fully disclosed and that the evaluation was not based solely on theory or calculation.
(4) The evaluation results referred to in subsections (f)(2) and (f)(3) shall contain the same information and shall be reported following the same general format as the EPA standard results sheet as any corresponding EPA test procedure.
(g) The underground storage tank owner or operator shall notify the local agency 48 hours before conducting a tank or piping integrity test unless the notification requirement is waived by the local agency. Within 30 calendar days of completion of an underground storage tank or piping integrity test, the tank owner or operator shall provide the local agency with a report. The results of any underground storage tank tests, other than those required by this article, performed on the underground storage tank or piping to detect an unauthorized release shall be reported by the owner or operator to the local agency within 30 calendar days of completion of the test. The report shall be presented in written and/or tabular format, as appropriate, and shall be at a level of detail appropriate for the release detection method used.


Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Section 25292, Health and Safety Code; 40 CFR 280.40-280.45.






s 2643.1. Tank Integrity Testing Requirements.
Tank integrity testing shall meet the requirements of section 2643(f) and shall be conducted using one of the two methods in subsections (a) or (b) below. Tank integrity test methods shall account for the effects of thermal expansion or contraction of the product, vapor pockets, tank deformation, evaporation or condensation, and the presence of water in the backfill:
(a) A volumetric tank integrity test shall be capable of detecting a release of 0.1 gallon per hour from any portion of the tank when the tank is at least 65% full of product or at any product level if the product-filled portion of the tank is tested under pressure equivalent to that of a full tank. If any volumetric tank integrity test is conducted at a product level lower than the overfill protection device set point, a test meeting the requirements of subsection (b) must be used to test the ullage portion of the tank.
(b) A nonvolumetric tank integrity test shall be capable of detecting a release of 0.1 gallon per hour from any portion of the tank at any product level.


Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Section 25292, Health and Safety Code; and 40 CFR 280.40 - 280.45.






s 2644. Non-Visual Monitoring/Qualitative Release Detection Methods.
(a) An owner or operator who is required, pursuant to section 2641, to establish a non-visual monitoring program, shall comply with the requirements of this section if a qualitative release detection method is used. Each qualitative release detection method, including interstitial monitors, shall have an independent third-party evaluation to certify accuracy and response time of the detection method in accordance with procedures in Appendix IV. Examples of qualitative release detection methods that may be used are in Appendix III.
(b) If vadose zone monitoring is used as a release detection method, it shall be conducted in accordance with section 2647.
(c) If ground water monitoring is used as a release detection method, it shall be conducted in accordance with section 2648.
(d) A qualitative release detection method which includes the installation of monitoring wells or drilling other borings shall comply with installation, construction, and sampling and analysis procedures in section 2649.
(e) Underground pressurized piping that is monitored at least monthly by a non-visual qualitative release detection method satisfies the annual tightness test requirement of section 25292(e) of the Health and Safety Code.


Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Section 25292, Health and Safety Code; 40 CFR 280.43.




s 2644.1. Enhanced Leak Detection.
(a) An owner or operator who is required, pursuant to section 2640(e), to implement a program of enhanced leak detection or monitoring shall comply with the requirements of this section as follows:
(1) Enhanced leak detection means a test method that ascertains the integrity of an underground tank system by introduction, and external detection, of a substance that is not a component of the fuel formulation that is stored in the tank system.

(2) The enhanced leak detection test method shall be third party certified, in accordance with section 2643(f), for the capability of detecting both vapor and liquid phase releases from the underground storage tank system. The enhanced leak detection test method shall be capable of detecting a leak rate of at least 0.005 gph, with a probability of detection of at least 95% and a probability of false alarm no greater than 5%.
(3) Owners and operators subject to the requirements of this section shall have a program of enhanced leak detection reviewed and approved by the local agency within 6 months following notification by the board The enhanced leak detection shall be implemented no later than 18 months following receipt of notification from the board and repeated every 36 months thereafter.
(4) Owners and operators of underground storage tanks subject to the requirements of this section must notify the local agency at least 48 hours prior to conducting the enhanced leak detection test unless this notification requirement is waived by the local agency.
(5) Owners and operators of underground storage tanks subject to the requirements of this section shall submit a copy of the enhanced leak detection test report to the board and the local agency within 60 days of completion of the test.


Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Sections 25283, 25291, 25292 and 25292.4, Health and Safety Code; and 40 CFR 280.40 and 280.41.





s 2645. Manual Tank Gauging and Testing for Small Tanks.
(a) Manual tank gauging may be used as part of a non-visual monitoring program for existing underground storage tanks which have a total system capacity of 2,000 gallons or less and which can be taken out of service for at least 48 or 72 continuous hours each week as indicated in Table 4.1.
(b) Manual tank gauging shall be conducted weekly in accordance with subsection (d). Piping testing shall be conducted in accordance with section 2643(c), (d), or (e). Tanks with a capacity of 1,001 to and including 2,000 gallons shall also receive a tank integrity test each year. Tanks with a capacity of 551 to and including 1,000 gallons shall also have an annual tank integrity test unless the gauging period is 60 hours or more. Requirements of section 2643(b) do not apply to tanks which are monitored in accordance with this section.
(c) Manual tank gauging shall not be used on tanks with secondary containment and shall not be used as a leak detection method after December 22, 1998, for underground storage tanks with a capacity greater than 1,000 gallons.
(d) Owners or operators of existing underground storage tanks who use manual tank gauging as part of a non-visual monitoring program shall conduct weekly gauging according to the following specifications:
(1) Tank liquid level measurements shall be taken at the beginning and end of a gauging period which shall be at least 36 or 60 continuous hours as set forth in Table 4.1 during which no liquid is added to or removed from the tank. The underground storage tank shall be secured to prevent inputs or withdrawals during the gauging period. No product shall be added to the tank within the 12- hour period preceeding the gauging period. The liquid level measurements shall be based on an average of two consecutive stick readings at both the beginning and end of the gauging period; and,
(2) The equipment used shall be capable of measuring the level of the product over the full range of the tank's height to the nearest one-eighth of an inch; and,
(3) If the variation between beginning and ending measurements exceeds the weekly or monthly standards set forth in Table 4.1, a second 36-hour or 60-hour test shall begin immediately and all measurements and calculations checked for possible errors. If the second test confirms a variation which exceeds the weekly or monthly standards in Table 4.1, a tank integrity test shall be conducted within 72 hours of completion of the second test. The local agency may extend this 72-hour period up to 30 calendar days, if all contents of the underground storage tank are safely and properly removed within the 72-hour period.
(e) If the results of a tank integrity test confirm an unauthorized release, the owner or operator shall comply with the release reporting requirements of Article 5 and shall replace, repair, upgrade, or close the underground storage tank in accordance with the applicable provisions of this chapter.
Table 4.1

Manual Tank Gauging Measurement Standards


Weekly Monthly Testing Total Time
Standard Standard Period Out of Service
Tank Size One Test Average of [FNa1] (hours) (hours)
(in Gallons) (Gallons) 4 tests
(Gallons)
550 or less 10 5 36 48
551 to and
including 1,000 12 6 60 72
[FNaa1] 551 to and
including 1,000 13 7 36 48
[FNaa1] 1,001 to and
including 2,000 26 13 60 72

[FNa1] The tank must be taken out of service at least 12 hours before the test (gauging) period begins.
[FNaa1] An annual tank integrity test is required.


Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Sections 25292 and 25293, Health and Safety Code; 40 CFR 280.43.




s 2646. Manual Inventory Reconciliation.
(a) Manual inventory reconciliation may be used as part of a non-visual monitoring program set forth in section 2643(b)(4) for existing underground storage tanks which contain motor vehicle fuels.
(b) After January 1, 1993, manual inventory reconciliation shall not be used to comply with the requirements of this article where the existing ground water level or the highest anticipated ground water level is less than 20 feet below the bottom of the tank. The ground water level shall be determined in accordance with the requirements of section 2649(c). After December 22, 1998, manual inventory reconciliation shall not be used to satisfy underground storage tank monitoring requirements.
(c) Each underground storage tank shall be individually monitored using a method that incorporates the following procedures:
(1) Separate daily measurements shall be taken and recorded for both the motor vehicle fuel and any water layer. For the purpose of this section, "daily" means at least every day that motor vehicle fuel is added to or withdrawn from the tank, but no less than five days per week. The number of days may be reduced by the number of public holidays that occur during the week if there is no input to or withdrawal from the tank on the holiday. Local agencies may reduce the frequency of monitoring to not less than once every three days at facilities that are not staffed on a regular basis, provided that the monitoring is performed every day the facility is staffed. Measurements shall be:
(A) taken when no substance is being added to or withdrawn from the tank;
(B) performed by the owner, operator, or other designated persons who have had appropriate training;
(C) based on the average of two readings if dipstick or tape measurements are used.
(D) determined by equipment capable of measuring the level of the product over the full range of the tank's height to the nearest one-eighth of an inch. If a dipstick is used to determine the product level, a substance capable of rendering the readings legible shall be applied to the dipstick before use, if necessary to obtain accurate readings;
(E) determined by equipment capable of measuring, to the nearest one-eighth of an inch, water present in the bottom of the tank. If a dipstick is used, water-finding paste shall be applied to the dipstick. If the tank is not level, and the measurements are taken manually, the measurements shall be taken at the lowest end of the tank.
(F) measured at the center of the longitudinal axis of the tank if access is available or measured at the lowest end of the tank with a calibration measurement at both ends, if possible, to determine if any tank tilt exists, and, if so, its magnitude; and

(G) converted to volume measurements based on a calibration chart for the tank. This chart shall, where feasible, take into account the actual tilt of the tank.
(2) Daily readings shall be taken for input and withdrawals. The amount of product inputs indicated by delivery receipt shall be compared with measurement of the tank inventory volume before and after delivery. Product input shall be determined by a method that introduces the least amount of error in the monthly inventory reconciliation calculations. Underground storage tanks that are connected by a manifold may require time for the level to stabilize before a measurement is taken. Product shall be delivered to the tank through a drop tube that extends to within 12 inches of the bottom of the tank.
(d) The daily variation shall be the difference between the physically measured inventory in storage and the calculated inventory in storage. The physically measured inventory shall be measured daily by taking a liquid level measurement and converting it to gallons using a calibration chart. The calculated inventory shall be determined daily by adding the amount of product added to the tank and subtracting the withdrawals from the inventory measured on the previous day. These variations shall be algebraically summed for a period of one month. If the absolute value of the monthly variations exceeds a variation of 1.0 percent of the total monthly input to or withdrawals from the tank plus 130 gallons, the variation shall be investigated in accordance with subsection (e).
(e) If the monthly manual inventory reconciliation exceeds the allowable variation, the owner or operator shall:
(1) within 24 hours of completing inventory reconciliation which exceeds the allowable variation, notify the local agency of the suspected unauthorized release;
(2) within 24 hours of discovering a variation which exceeds the allowable variation, review the inventory records for the preceding 30 days to determine if an error in calculations was made. If investigation shows that an error in calculations was made and that variations have not been exceeded, no further steps need to be taken;
(3) within 24 hours of discovering a variation which exceeds an allowable variation, have all readily accessible facilities carefully inspected for leakage by appropriately trained persons. If an unauthorized release is detected, the owner or operator shall comply with the requirements of Article 5. If no unauthorized release is detected, the owner or operator shall continue with the following steps:
(4) have dispenser meters, which determine the amount of product withdrawn from the tank, checked and recalibration, if necessary, within 24 hours of completing the procedure required in subdivision (3) above. Dispenser meters shall comply with California Code of Regulations, Title 4, Division 9, "Division of Measurement Standards, Department of Food and Agriculture." Meters shall be inspected by the County Department of Weights and Measures or a device repairman as defined in the California Business and Professions Code, Division 5, Chapter 5.5. This subdivision applies to all meters used for determining withdrawals, including those at non-retail facilities;
(5) continue to conduct inventory reconciliation according to the requirements of this section. If a second 30-day period of data confirms the initial results, the owner or operator shall comply with the requirements of Article 5; and
(6) conduct additional tests or investigations as required by the local agency and, if applicable, replace, repair, upgrade, or close the tank in accordance with the applicable provisions of this chapter.
(f) Whenever any of the steps in subsection (e) of this section are performed, the results shall be documented in the monitoring record required under section 2712. If completion of any of the steps in subsection (e) indicates that the apparent excessive variation is not due to a release or tank failure, the remainder of the steps need not be completed.
(g) On an annual basis, the owner or operator shall submit a written statement to the local agency verifying under penalty of perjury that all monthly reports were summarized and that all data are within allowable variations. If data exceeded allowable variations, the owner or operator shall provide the local agency with a list of times, dates, and corresponding variations which exceeded allowable variations. This information shall be signed by the owner or operator under penalty of perjury.
(h) The transfer of hazardous substances into and out of the underground storage tank may continue while the steps in subsection (e) are being implemented, provided the steps are completed within the specified periods. Daily inventory readings and monthly reconciliation shall continue while the steps are being implemented.
(i) Dispenser meters which determines the amount of product withdrawn from the tank shall comply with the provisions of Title 4, Division 9, "Division of Measurement Standards, Department of Agriculture." Meters shall be inspected and recalibrated by the County Department of Weights and Measures or a device repairman as defined in Division 5, Chapter 5.5 of the Business and Professions Code.


Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Sections 25291 and 25292, Health and Safety Code; 40 CFR 280.43.




s 2646.1. Statistical Inventory Reconciliation.
(a) When approved by the local agency, statistical inventory reconciliation may be used as part of a non-visual monitoring program, set forth in section 2643(b)(3), for existing underground storage tanks which contain motor vehicle fuel.
(b) Each underground storage tank shall be individually monitored using a method prescribed by section 2646(c).
(c) On a monthly basis, the tank owner must provide the minimum number of data records to the statistical inventory reconciliation provider as required by that provider. The previous month's data may be included with the current month's data to total the minimum number of records necessary to complete the statistical inventory reconciliation. Data submissions to the statistical inventory reconciliation provider and subsequent receipt of reports from the provider shall be completed monthly within 20 calendar days of the end of the data collection period. To give the owner or operator an opportunity to become proficient in the use of statistical inventory reconciliation, the requirements in subsection (d) do not apply if any of the first three reports are inconclusive. The owner or operator shall inform the local agency of the results of the first three reports, regardless of the results.
(d) If the results of a report are inconclusive or indicate a possible unauthorized release, the owner or operator shall, within 24 hours of receipt of the report:
(1) notify the local agency of the possible unauthorized release, and within 10 calendar days, submit a copy of the report to the local agency. The local agency may allow up to 10 additional calendar days in which to submit the report;

(2) inspect the inventory records for errors to determine if data were collected properly;
(3) have all accessible portions of the underground storage tank system inspected for leakage by appropriately trained persons. If an unauthorized release is detected, the owner or operator shall comply with the requirements of Article 5. If no unauthorized release is detected, the owner or operator shall continue with the steps in subdivision (4) below:
(4) have dispenser meters, which determine the amount of product withdrawn from the tank, checked and recalibrated if necessary within 48 hours of receipt of the report. Meters shall be recalibrated by the County Department of Weights and Measures or a device repair person as defined in the California Business and Professions Code, Division 5, Chapter 5.5. This subdivision applies to all meters used for determining withdrawals, including those at non-retail facilities. Dispenser meters shall comply with California Code of Regulations, Title 4, Division 9, "Division of Measurement Standards, Department of Food and Agriculture."
(e) Daily readings shall continue to be taken and recorded during the investigation specified in subsection (d) above. If the second statistical inventory reconciliation report does not indicate a tight system, the owner or operator shall comply with the release reporting requirements of Article 5.
(f) The owner or operator who reports a suspected release in accordance with subsection (e) above shall conduct additional tests or investigations as required by the local agency and, if necessary, replace, repair, upgrade, or close the tank in accordance with the applicable provisions of this chapter.
(g) A tank integrity test meeting the requirements of section 2643.1 is also required every two years when statistical inventory reconciliation is used. The first tank integrity test shall be conducted within the first year of implementation of a monitoring program which includes statistical inventory reconciliation.
(h) The owner or operation shall conduct a piping tightness test and, if necessary, a tank integrity test within 15 calendar days of receipt of two successive reports which are inconclusive or which indicate a possible unauthorized release. The local agency may also require a piping tightness test and, if necessary, a tank integrity test if frequent inconclusive results are reported.
(i) Piping connected to a tank which is monitored using statistical inventory reconciliation shall be tested in accordance with section 2643(c), (d), or (e).
(j) On an annual basis, the owner or operator shall submit a written statement to the local agency which indicates the results from the statistical inventory reconciliation reports for the previous 12 months.
(k) Dispenser meters which determine the amount of product withdrawn from the tank shall comply with the provisions of Title 4, Division 9, "Division of Measurement Standards, Department of Agriculture." Meters shall be inspected and recalibrated by the County Department of Weights and Measures or a device repair person as defined in Division 5, Chapter 5.5 of the Business and Professions Code.


Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Sections 25291 and 25292, Health and Safety Code; and 40 CFR 280.43.




s 2647. Vadose Zone Monitoring Requirements.
(a) Owners or operators of existing underground storage tanks who use vadose zone monitoring as part of a non-visual monitoring program shall comply with the requirements of this section. Vapor monitoring, soil-pore liquid monitoring, or a combination of these or other vadose zone monitoring methods may be used.
(b) Vadose zone monitoring shall not be used as the sole release detection method of non-visual monitoring where the monitoring well cannot be located within the backfill surrounding the tank, or where the existing ground water level or the highest anticipated ground water level, including intermittent perched ground water, is less than ten feet below the bottom of the tank. Ground water levels shall be determined in accordance with section 2649(c).
(c) Vadose zone vapor monitoring shall be conducted continuously. Other vadose zone monitoring shall be conducted at least weekly. All manual sampling in the vadose zone shall be conducted in accordance with section 2649(g).
(d) The number, location, and depths of vadose zone monitoring points shall be selected to achieve the objective specified in section 2641(a). Where possible, monitoring points shall be located within the excavation backfill surrounding the underground storage tank. The owner or operator shall determine the exact location of the underground storage tank and associated piping before attempting to install monitoring wells and/or devices pursuant to local agency approved.
(e) Vadose zone vapor monitoring shall comply with the following minimum requirements:
(1) The vapor characteristics of the stored product, or a tracer compound placed in the underground storage tank system, shall be sufficiently volatile to result in a vapor level that is detectable by the monitoring devices;
(2) Backfill materials and soils surrounding monitoring points shall be sufficiently porous to readily allow diffusion of vapors;
(3) The level of background contamination in the excavation zone and surrounding soils shall not interfere with the method used to detect releases from the underground storage tank;
(4) The monitoring devices shall be designed and operated to detect any significant increase in concentration above the background of the hazardous substance stored in the underground storage tank, a component or components of that substance, or a tracer compound placed in the tank system;
(5) The location and depth of each monitoring point shall be placed according to the most probable movement of vapor through the backfill or surrounding soil;
(6) Vapor monitoring wells located in the backfill shall be constructed so that any unauthorized release that may pond at the horizontal interface between the backfill and natural soils can be detected in the vapor well; and
(7) All vapor monitoring wells shall be installed, constructed, and sampled according to the requirements specified in sections 2649(b), (c), (e) and (f).
(f) Soil-pore liquid monitoring and other forms of vadose zone monitoring shall comply with the following minimum requirements:
(1) The stored substance shall be susceptible to detection by the proposed release detection method;
(2) The stored substance shall not corrode or otherwise attack the materials from which the detection system is constructed or otherwise render the detection system inoperable or inaccurate; and
(3) Site-specific conditions (e.g., precipitation, ground water, soil-moisture, background contamination) shall not interfere with the operability and accuracy of the release detection method.
(g) Compliance with the requirements of subsections (e) and (f) shall be based on a site-assessment including assessment of the underground storage tank excavation zone.


Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Section 25292, Health and Safety Code; 40 CFR 280.43.




s 2648. Ground Water Monitoring Requirements.
(a) Owners or operators of existing underground storage tanks who use ground water monitoring as part of a non-visual monitoring program shall comply with the requirements of this section. Ground water monitoring may be used in combination with other quantitative or qualitative release detection methods or, where permissible under this section, as the sole release detection method.
(b) Ground water monitoring may be used as the sole release detection method of non-visual monitoring for existing underground tanks only where all of the following conditions exist:
(1) The hazardous substance stored is immiscible with water and has a specific gravity of less than one;
(2) Continuous monitoring devices or manual methods are used which are capable of detecting the presence of at least one-eighth of an inch of free product on top of the ground water in the monitoring wells. This capability shall be certified by an independent third party using an appropriate evaluation procedure. Examples of acceptable evaluation procedures are in Appendix IV;
(3) The existing ground water level or the highest anticipated ground water level, including intermittent perched ground water, is less than 20 feet from the ground surface. These ground water levels shall be determined according to the requirements of section 2649(c);
(4) The hydraulic conductivity of the soil(s) between the underground storage tank and the monitoring wells or devices is at least 0.01 cm/sec (e.g., the soil consists of gravels, coarse to medium sands, or other permeable materials);

(5) The ground water proposed for monitoring has no present beneficial uses (e.g., domestic, municipal, industrial, agricultural supply) or is not hydraulically connected to ground or surface water which has actual beneficial uses; and
(6) Monitoring wells or devices are located within the excavation zone or as close to the excavation zone as feasible.
(c) Compliance with the conditions specified in subsection (b) shall be based on a site-assessment, including assessment of the areas within and immediately below the underground storage tank excavation zone. If ground water monitoring is approved as the sole release detection method of a non-visual monitoring program, the number and location of the monitoring wells and/or devices as approved by the local agency shall also be based on this site-assessment with minimum requirements as follows:
(1) Single tank - two wells, one at each end of the tank.
(2) Two or three tanks - three wells equally spaced.
(3) Four or more tanks - four wells, at least two of which shall be downgradient and the remainder equally spaced.
(4) Pipelines - additional wells, if needed, as determined by the local agency.
(d) Ground water monitoring shall be conducted at least monthly or continuously. Any continuous monitoring system shall be capable of detecting the presence of hazardous substance on top of the ground water in the monitoring well and shall allow periodic collection of samples. Ground water samples shall be analyzed by visual observation or field or laboratory analysis as approved by the local agency depending on the method of monitoring and the constituents being evaluated. The local agency may require periodic laboratory analysis where visual observation or field analysis does not provide an adequate degree of detection as compared to that of laboratory analysis. Sampling conducted which requires field or laboratory analysis shall comply with the minimum requirements of section 2649(g).
(e) The number, location, and depths of ground water monitoring wells shall be selected to achieve the objective specified in section 2641(a). Monitoring wells shall be located as close as possible to the underground storage tank or the perimeter of the underground storage tank cluster, subject to the review and approval of the local agency.


Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Section 25292, Health and Safety Code; 40 CFR 280.43.





s 2649. Well Construction and Sampling Requirements.
(a) Owners or operators who use a qualitative release detection method shall comply with the requirements of this section and any applicable requirements of sections 2644, 2647, and 2648.
(b) The installation of all monitoring wells and the drilling of all other borings shall be in accordance with local permitting requirements or, in their absence, with the following requirements:

(1) All monitoring wells and all other borings shall be logged during drilling according to the following requirements:
(A) Soil shall be described in the geologic log according to the Unified Soil Classification System as presented in Geotechnical Branch Training Manual Numbers 4, 5, and 6, published in January of 1986 (available from the Bureau of Reclamation, Engineering and Research Center, Attention: Code D-7923-A, Post Office Box 25007, Denver, Colorado 80225);
(B) Rock shall be described in the geologic log in a manner appropriate for the purpose of the investigation;
(C) All wet zones above the water table shall be noted and accurately logged. Where possible, the depth and thickness of saturated zones shall be recorded in the geologic log; and
(D) Geologic logs shall be prepared by a professional geologist or civil engineer, who is registered or certified by the State of California and who is experienced in the use of the Unified Soil Classification System. The geologic logs may also be prepared by a technician trained and experienced in the use of the Unified Soil Classification System who is working under the direct supervision of one of the aforementioned professionals, provided that the professional reviews the logs and assumes responsibility for the accuracy and completeness of the logs.
(2) All drilling tools shall be thoroughly steam cleaned immediately before each boring is started;
(3) All well casings, casing fittings, screens, and all other components that are installed in a well shall be thoroughly cleaned before installation;
(4) Soil and water sampling equipment and materials used to construct a monitoring well shall be compatible with the stored hazardous substance and shall not donate, capture, mask, or alter the constituents for which analyses will be made. All perforated casings used in the construction of monitoring wells shall be factory perforated;
(5) Drilling fluid additives shall be limited to inorganic, non-hazardous materials which conform to the requirements of subsection (b)(4). All additives used shall be accurately recorded in the boring log;
(6) Representative samples of additives, cement, bentonite, and filter media shall be retained for 90 calendar days for possible analysis for contaminating or interfering constituents;
(7) If evidence of contamination is detected by sight, smell, or field analytical methods, drilling shall be halted until a responsible professional determines if further drilling is advisable;
(8) All borings which are converted to vadose zone monitoring wells shall have the portion of the boring which is below the monitored interval sealed with approved grout;
(9) All borings which are not used for ground water or vadose zone monitoring shall be sealed from the ground surface to the bottom of the boring with an approved grout. All slurry-type grouts used to seal an abandoned boring or an abandoned well shall be emplaced by the tremie method; and
(10) All monitoring wells shall be clearly marked and secured to avoid unauthorized access and tampering. Surface seals may be required by the local agency.
(c) When installing a vadose zone or ground water monitoring well, the highest anticipated ground water level and existing ground water level shall be determined. Highest anticipated ground water levels shall be determined by reviewing all available water level records for wells within one mile of the site. Existing site ground water levels shall be established either by reviewing all available water level measurements taken within the last two years at all existing wells, within 500 feet of the underground storage tank which are perforated in the zone of interest, or by drilling at least one exploratory boring constructed as follows:
(1) The exploratory boring shall be drilled downgradient, if possible, and as near as possible to the underground storage tank within the boundaries of the property encompassing the facility, but no further than ten feet from the underground storage tank;
(2) The exploratory boring may be of any diameter capable of allowing the detection of first ground water;
(3) The exploratory boring shall be drilled to first perennial ground water, or to a minimum depth of 20 feet for vadose zone monitoring wells, or to a minimum depth of 30 feet for ground water monitoring wells if permitted by site lithology;

(4) If ground water is encountered, and ground water monitoring is the monitoring method, the boring shall be converted to a ground water monitoring well consistent with the provisions of this section; and
(5) If ground water is encountered, but ground water monitoring is not the monitoring method, or if the exploratory boring does not encounter ground water, the boring shall be sealed in accordance with the provisions of subsection (b)(9).
(d) In addition to the requirements of subsection (b), all ground water monitoring wells shall be designed and constructed according to the following minimum requirements:
(1) Ground water monitoring wells shall extend at least 20 feet below the lowest anticipated ground water level and at least 15 feet below the bottom level of the underground storage tank. However, wells shall not extend through laterally extensive impermeable zones that are below the water table and that are at least five feet thick. In these situations, the well shall be terminated one to two feet into the impermeable zone;

(2) Ground water monitoring wells shall be designed and constructed as filter packed wells that will prevent the migration of the natural soil into the well and with factory perforated casing that is sized to prevent migration of filter material into the well;
(3) Ground water monitoring well casings shall extend to the bottom of the boring and shall be factory perforated from a point of one foot above the bottom of the casing to an elevation which is either five feet above the highest anticipated ground water level or to within three feet of the bottom of the surface seal or to the ground surface, whichever is the lowest elevation;
(4) All well casings shall have a bottom cap or plug;
(5) Filter packs shall extend at least two feet above the top of the perforated zone except where the top two feet of the filter pack would provide cross-connection between otherwise isolated zones or where the ground surface is less than ten feet above the highest anticipated ground water level, the local agency may reduce the height of the filter pack so long as the filter pack extends at least to the top of the perforated zone. Under such circumstances, additional precautions shall be taken to prevent plugging of the upper portion of the filter pack by the overlying sealing material;

(6) Ground water monitoring wells shall be constructed with casings having a minimum inside diameter of two inches and shall be installed in a boring whose diameter is at least four inches greater than the outside diameter of the casing;
(7) Ground water monitoring wells shall be sealed in accordance with local permitting requirements or, in their absence, with the Department of Water Resources Standards for Well Construction (Reference Bulletins 74-81 and 74-90 on Water Well Standards are available from the Department of Water Resources, Sacramento);
(8) Seventy-two or more hours following well construction, all ground water monitoring wells shall be adequately developed and equilibrium shall be established prior to any water sampling;
(9) Well heads shall be provided with a water-tight cap and shall be enclosed in a surface security structure that protects the well from surface water entry, accidental damage, unauthorized access, and vandalism. Traffic lids shall be clearly marked as monitoring wells; and

(10) Pertinent well information including well identification, well type, well depth, well casing diameters (if more than one size is used), and perforated intervals shall be permanently affixed to the interior of the surface security structure and the well identification number and well type shall be affixed on the exterior of the surface security structure.
(e) In addition to the requirements of subsection (b), all vadose zone vapor monitoring wells shall be cased and sealed as follows:
(1) Well casings for vapor monitoring shall be fully perforated except for the portion adjacent to a surface seal and that portion used as a free liquid trap;
(2) Surface seals for vapor wells that are completed no more than five feet below the bottom of the underground storage tank and which are above any free water zones may be required at the discretion of the local agency on a site-specific basis;
(3) If surface seals for vapor wells are completed in or below a potential free water zone, the seal shall not extend below the top of the underground storage tank; and

(4) Vapor wells need not be sealed against infiltration of surface water if constructed wholly within backfill that surrounds the underground storage tank and which extends to the ground surface.
(f) Undisturbed (intact) soil samples shall be obtained from all borings for the installation of monitoring wells and all other borings and analyzed according to the following minimum requirements, unless the local agency waives this requirement under this subsection:
(1) Borings shall be drilled and sampled using accepted techniques which do not introduce liquids into the boring and which will allow the accurate detection of perched and saturated zone ground water. If this cannot be accomplished using acceptable techniques, the requirement for soil sampling may be waived by the local agency provided, however, that installation of the vadose zone or ground water monitoring system shall be completed; and provided further, that once below the water table, borings need not be advanced using the same method that was used in the vadose zone;
(2) Soil samples shall be obtained at intervals of five feet or less and at any significant change in lithology, beginning at the ground surface. Sampling is not required in unweathered bedrock which has little on no permeability;

(3) A soil sample shall be obtained at the termination depth of a dry boring regardless of the spacing interval;
(4) Soil samples shall be of sufficient volume to perform the designated analyses including soil vapor and soil extract analyses and to provide any specified replicate analyses;
(5) Soil samples shall be acquired, prepared, preserved, stored, and transported by methods that are appropriate for the objectives of the investigation which safeguard sample integrity and satisfy the requirements of subsection (g);
(6) Samples shall be analyzed in a State-certified laboratory by methods that provide quantitative or qualitative results. Lower detection limits shall be verified by the laboratory;
(7) Samples shall be analyzed for one or more of the most persistent constituents that have been stored in the underground storage tank. If the use of the underground storage tank has historically changed, samples shall be analyzed for at least one constituent from each period of use. If the hazardous substance is known to degrade or transform to other constituents in the soil environment, the analysis shall include these degradation and/or transformation constituents;
(8) If hazardous substances known or suspected to have been contained in the underground storage tank are detected at concentrations in excess of background concentrations (background concentrations shall be applicable only if the constituent occurs naturally at the site), further soil analysis is not necessary pursuant to this subsection. The hazardous substance(s) shall be assumed to have originated from the underground storage tank. In this situation, the remainder of the soil samples need not be analyzed pursuant to these regulations and the owner or operator shall comply with subdivision (9) below. A permit shall not be granted unless further detailed investigation clearly establishes that the underground storage tank is not the source of the hazardous substance or that it has been properly repaired since the unauthorized release and that any subsequent unauthorized release from the underground storage tank can be detected despite the presence of the hazardous substance already in the environment; and
(9) If soil analysis indicates that an unauthorized release has occurred, the owner or operator shall comply with the release reporting requirements of Article 5 and shall replace, repair, upgrade, or close the underground storage tank pursuant to the applicable provisions of this chapter.
(g) The qualitative release detection method shall include consistent sampling and analytical procedures, approved by the local agency, that are designed to ensure that monitoring results provide a reliable indication of the quality of the medium (e.g., ground water, soil-pore liquid, soil vapor, or soil) being monitored. Some acceptable procedures are listed as references in Appendix I, Table C. The owner or operator shall provide a written detailed description, to be specified in the permit and to be maintained as part of the records required under section 2712 of Article 10, of the procedures and techniques for:
(1) Sample collection (e.g., purging techniques, water level, sampling equipment, and decontamination of sampling equipment);
(2) Sample preservation and shipment;
(3) Analytical procedures; and
(4) Chain-of-custody control.


Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Section 25292, Health and Safety Code; 40 CFR 280.43.





s 2650. Reporting and Recording Applicability.
(a) The requirements of this article apply to all owners or operators of one or more underground storage tanks storing hazardous substances.
(b) The owner or operator shall record or report any unauthorized release from the underground storage tank, and any spill or overfill, in accordance with the appropriate sections of Chapter 6.7 of Division 20 of the Health and Safety Code and this article.
(c) The owner or operator of an underground storage tank with secondary containment shall record any unauthorized release described in section 25294 of the Health and Safety Code in accordance with section 2651.
(d) Owners or operators subject to the requirements of this article shall report all spills and overfills in accordance with section 2652.
(e) The owner or operator of an underground storage tank shall report to the local agency any unauthorized release described in sections 25295 and 25295.5 of the Health and Safety Code, and shall also record and report any of the following conditions in accordance with section 2652:
(1) Any unauthorized release recorded or reported under subsections (c) or (d) which the owner or operator is unable to clean up or which is still under investigation within eight hours of detection;
(2) The discovery by the owner or operator, local agency, or others of released hazardous substances at the site of the underground storage tanks or in the surrounding area. This includes the presence of free product or vapors in soils, basements, sewer and utility lines, and nearby surface or drinking waters;

(3) Unusual operating conditions observed by the owner or operator including erratic behavior of product dispensing equipment, the sudden loss of product from the underground storage tank, or an unexplained presence of water in the tank, unless system equipment is found to be defective, but has not leaked, and is immediately repaired or replaced; and
(4) Monitoring results from a release detection method required under Article 3 or Article 4 that indicate a release may have occurred, unless the monitoring device is found to be defective, and is immediately repaired, recalibrated or replaced, and additional monitoring does not confirm the initial results.
(f) The reporting requirements of this article are in addition to any reporting requirements in section 13271 of Division 7 of the California Water Code and other laws and regulations.


Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Sections 25294, 29295 and 25295.5, Health and Safety Code; 40 CFR 280.52.





s 2651. Recording Requirements for Unauthorized Releases.
(a) Owners or operators required by section 2650 to record a release or condition shall comply with the requirements of this section.
(b) The operator's monitoring records, as required under section 2712 of Article 10, shall include:
(1) The operator's name and telephone number; (continued)