Single-Walled Vent or Riser Piping

Underground storage tanks installed between July 1, 1987 and June 30, 2003 with single-walled vent or riser piping meeting California Code of Regulations, title 23, division 3, chapter 16 (UST Regulations), section 2636(a)(1) cannot also use the overfill prevention equipment (OPE) exemption outlined in UST Regulations, section 2635(c)(2).  Single-walled vent or riser piping installed during this period must be equipped with OPE that meets the performance standards of UST Regulations, sections 2635(c)(1)(B) or (C).

As previously discussed in UST Technical Advisory Group meetings, conferences, UST monthly updates and Local Guidance letter 150-3 CUPAs cannot waive the OPE requirement for single-walled vent or riser piping that uses the secondary containment exemption identified in UST Regulations, sections 2636(a)(1).  The secondary containment exemption requires single-walled vent or riser piping to be equipped with OPE that meets UST Regulations, sections 2635(c)(1)(B) or (C).

For single-walled vent or riser piping that improperly uses the OPE exemption, owners and/or operators can bring their USTs back into compliance by modifying or repairing as follows:

  1. Secondarily contain all vent and/or riser piping; or
  2. Systems with an automatic tank gauge and vent restrictor installed before October 1, 2018, in accordance with UST Regulations, section 2635(c)(1)(B), must be inspected in accordance with UST Regulations, section 2637.2 and marked as “Audible/Visual Alarms and Ball Float” for the primary OPE in the California Environmental Reporting System (CERS); or
  3. Install new or inspect existing positive shutoff in accordance with UST Regulations, sections 2635(c)(1)(C) and 2637.2 and mark the primary OPE as “Fill tube shutoff valve” in CERS.

During the CUPA Performance Evaluation, State Water Board staff will review CERS data and UST facility files to determine if any USTs with single-walled vent or riser piping in the CUPA’s jurisdiction do not meet UST Regulations and Health and Safety Code, chapter 6.7 (HSC) requirements.  CUPAs should identify if any USTs with single-walled vent or riser piping use both exemptions within their jurisdiction.  If a CUPA discovers these types of UST systems in their jurisdiction, the CUPA must take appropriate enforcement action, pursuant to UST Regulations and HSC, and provide owners and/or operators of these facilities with the options listed above to return their USTs to compliance.