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UST Program - Available Local Guidance (LG) Letters

UST Program - Local Guidance (LG) 152


March 18, 1998

To: Local Agencies and Other Interested Parties

The purpose of this letter is to clarify how California’s Underground Storage Tank (UST) laws and regulations apply to the aboveground piping associated with an UST system. Part I discusses the applicability of the UST laws and regulations and Part II summarizes the corrosion protection, monitoring, secondary containment, and upgrade requirements.

Part I. Applicability Of The UST Laws And Regulations To The Aboveground  Piping Associated with An UST System

Aboveground piping that is part of an UST system is subject to the provisions of Chapter 6.7 of the Health and Safety Code (H&SC) and Title 23, Division 3, Chapter 16 of California Code of Regulations (CCR).  California’s requirements are more stringent than the federal UST regulations which exclude the unburied portion of a UST system.

For example, under-dispenser piping and marina piping (the entire section of the piping that connects a land-based UST to the dispenser located on a marina dock) that are associated with a UST systems are subject to Title 23 CCR regulations.

Legal Authorities:

  • Section 25281(x) H&SC state that , “Underground Storage Tank means any one or combination of tanks, including piping connected thereto, which is used for the storage of hazardous substances and which is substantially or totally beneath the surface of the ground”.
  •  Section 2611 CCR states that , “Substantially beneath the surface of the ground means that at least 10 percent of the UST system volume, including the volume of any connected piping, that is below the ground surface or enclosed below earthen materials”.
  • Section 25281(y) H&SC states that, “underground tank system or tank system means an underground storage tank, connected piping, ancillary equipment, and containment system, if any”.
  • Section 25281.5 H&SC states that, “pipe means all parts of any pipelines, used in connection with the storage of hazardous substances, including, but not limited to, valves and other appurtenances connected to the pipe, pumping units, fabricated assemblies associated with pumping units, and metering and delivery stations and fabricated assemblies therein”.


The following provides a clarification for the two issues often raised by the regulated community regarding applicability of the UST requirements to aboveground piping associated with a UST system:
    1. As defined in Section 2611 CCR, “connected piping” means all underground piping including valves, elbows, joints, flanges, and flexible connectors attached to a tank system through which hazardous substances flow.  This definition was incorporated into the California regulations from 40 CFR 281.12 (Federal UST regulations) during the 1994 rulemaking.  This definition has led to the misinterpretation that above ground piping associated with an UST is not part of the system.  However, excluding the aboveground piping associated with a UST system from the regulations is not consistent with the legal authorities cited above.  If the intent of the law was to exclude this piping, it would be listed in the exclusions of Section 25281.5 H&SC.
    2. Section 25281.5(a)(3) H&SC excludes, “unburied delivery hoses, vapor recovery hoses, and nozzles which are subject to unobstructed visual inspection for leakage” from the definition of piping.  Some have suggested that the shore-to-dock flexible piping is considered a delivery hose and therefore, is exempt from the UST regulations.  A delivery hose refers to the portion of the system that transfers fuel from a dispensing unit to vehicles.  Shore-to-dock piping and under-dock piping connects a UST to the fuel dispenser located on the marina dock and is not a “delivery hose.”

Part II. Construction And Monitoring Requirements For Aboveground Piping Associated with an UST System

Corrosion Protection

The exterior surface of piping that is made of corrodible material and is in contact with soil or water must be protected against corrosion.  Piping constructed of fiberglass-reinforced plastic, flexible non-corrodible material, and steel with cathodic protection fulfill corrosion protection requirements.  Corrodible piping that is exposed to an open corrosive environment may also need to be protected from corrosion (e.g. coating).


Single-wall piping - All single-wall piping must be monitored using a method that will detect leaks “at the earliest possible opportunity” [Section 2641(a) CCR]. Monitoring requirements are covered in Section 2641 CCR. Visual monitoring requirements are in Section 2642 CCR and non-visual monitoring requirements are in Section 2643 CCR.

Visual Monitoring - Piping that is exposed and offers an unobstructed view of all surfaces may be inspected visually. If the exposed piping is close to surface water or is situated such that product may leak into surface water, visual monitoring alone may not be approved by the local agency. Local agencies may require additional or more frequent monitoring plan based on the reliability and consistency of the existing or proposed monitoring plan and the proximity of the UST system to surface waters [Section 2641 (g) CCR]. For piping located at Marinas, due to proximity to surface water, local agencies may require additional monitoring such as a line tightness test.

Non-Visual Monitoring - Pressurized piping must be monitored using a combination of an automatic line leak detector with positive pump shut-off and an annual tightness test [Section 2643(c) CCR].  Suction piping requirements are covered in Section 2643(d) CCR and gravity piping requirements are covered in Section 2643(e) CCR.

Double-wall piping - All double-wall piping require a continuous monitoring system connected to an audible and visual alarm system. Requirements for monitoring double-wall piping are in Sections 2636(f) & (g) CCR.

Secondary Containment Requirement

Motor vehicle fuel systems - All piping that is connected to a tank installed after July 1, 1987, must have secondary containment [Section 2636(a) CCR].

Other hazardous substance systems  - All piping that is installed after January 1, 1984,  must have secondary containment [Section 2631(a) CCR].

Aboveground piping that is located inside a building or a vault or in an area where the surrounding structure provides secondary containment as approved by the local agency, is in compliance with this requirement.  Suction piping that meets the requirements of Section 2636(a)(3) CCR is exempt from the secondary containment requirement.

December 22, 1998 Upgrade Requirements

Motor vehicle fuel systems - Single-wall piping connected to a tank installed prior to July 1, 1987 must be retrofitted with corrosion protection if constructed of corrodible material [Section 2666(b) CCR]. Automatic line leak detectors installed on single-wall pressurized  piping must be upgraded to provide positive pump shut-off [Section 2666(c) CCR].

Other hazardous substance systems - This piping must be retrofitted with secondary containment [Section 2666(a) CCR] meeting the requirements of Section 2636 CCR.

Closure Requirements

Closure requirements of Articles 5, 7, and 11 CCR apply to the entire UST system including aboveground piping.

If you have any questions regarding this letter, please call Shahla Farahank at (916) 227-4350.

[Original signed by:]

Allan Patton, Manager
Underground Storage Tank Program

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