8.92.040   Amendments to Subchapter 16, underground tank regulations, Title 23 of the California Administrative Code.
   A.   Section 2632(C)(1)(D)(i) is changed to read:
   Laboratory or field analysis of the liquid. If the observed liquid constitutes an unauthorized release the local agency shall be notified within 24 hours. The release shall be treated as a reportable release pursuant to Section 2652 of this chapter.
   B.   The following is added to Section 2635(b)(8):
         (D)   A ball check valve which prevents the inflow of the hazardous substance into the primary vent pipe and the vapor recovery line on the underground storage tank.
   C.   Section 2641(c)(3)(A) is changed to read:
      (3)   Vadose zone monitoring, soil sampling, and underground storage tank testing:
         (A)   This monitoring alternative shall, at a minimum, include vadose zone monitoring and analysis of soil samples taken from the boring(s) made for vadose zone monitoring and tank testing. This alternative shall not be approved if the highest anticipated ground water, including intermittent, perched ground water is less than 30 feet deep, and this ground water has actual or potential beneficial uses (domestic, municipal, agricultural, or industrial supply) or is hydraulically connected to ground and surface waters which have actual or potential beneficial uses.
   D.   Section 2641(c)(3)(B) is changed to read:
   The determination that first ground water is significantly deeper than 30 feet shall be by an on-site boring(s) constructed according to the specifications in Subsection (p) of Section 2648 of this article or by evidence based on an evaluation pursuant to subsection 2648 (p) of this article.
   E.   The following are added to Section 2641(c), as subsections (9) and (10):
      (9)   Inventory reconciliation, underground storage tank testing, and testing for water in the underground storage tank.
         (A)   This monitoring alternative shall, at a minimum, utilize inventory reconciliation, underground storage tank testing and testing for water in the underground storage tank.
   The use of this alterative is limited to those underground storage tanks where perennial ground water is at the top of the underground storage tank.
         (B)   Inventory reconciliation shall be performed according to the procedures specified in Section 2644 of this article. The owner or operator of an underground storage tank that experiences an inventory reconciliation in excess of allowable variations shall implement the evaluation procedures specified in Subsection (f) of Section 2644 of this article within the times specified.
         (C)   Underground storage tank testing shall be performed yearly, at a minimum, according to the procedures specified in Section 2643 of this article.
         (D)   A test to determine if water is present in the underground storage tank shall be performed monthly. Upon detection of water in the underground storage tank the permitting authority shall be informed and a tank test per Section 2643 of this article may be required.
      (10)   Compare yearly usage.
         (A)   This monitoring alternative shall, at a minimum, keep inventory records of the yearly input and compare these records to the proceeding year(s). The use of this alternative is limited to those underground storage tanks which are personal residential underground storage tank(s).
         (B) A variation of yearly usage of 10 percent or greater shall be reported to the local agency. Procedures in Section 2652 for an unauthorized release may be required by the local agency.
   F.   Section 2646(a) is changed to read:
   All owners of existing underground storage tanks implementing one of the monitoring alternatives described in Section 2641 of this article which requires vapor or another form of vadose zone monitoring shall implement the vadose zone detection monitoring system pursuant to the manufacturer's and permitting authority's instruction or pursuant to Subsections (b) through (h) of this section.
   G.   Section 2648(p)(3) is changed to read:
   The exploratory boring shall be drilled to first perennial ground water or to a minimum depth of 100 feet for alternatives 2, 3, and 6, or to a minimum depth of 30 feet for alternatives 3 and 4.
   H.   Section 2648(q) is changed to read:
   All borings that are not used for ground water or vadose zone monitoring shall be sealed from the ground surface to the bottom of the boring with grout material consisting of neat cement or cement grout.
   I.   Section 2648(r) is changed to read:
   All borings that are converted to vadose zone monitoring wells in which the monitored interval is shallower than the total depth of the boring shall have the portion of the boring which is below the monitored interval sealed with grout material consisting of neat cement or cement grout.
   J.   Section 2648(v) is changed to read:
   If evidence of contamination is detected by sight, smell, or other field analytical methods, drilling shall be halted until the responsible professional determines if drilling deeper is advisable. The permitting authority shall be notified of the contamination within 24 hours.
   K.   Section 2671(a) is changed to read:
   This section applies to those underground storage tanks in which storage has ceased but where the owner or operator proposes to retain the ability to use the underground storage tank within 1 year for the storage of hazardous substances.
(Prior code § 16.01.026)