1. (a) Performance standards for UST systems.The owner or operator of an UST system shall ensure that such system complies with the following requirements.

   1. (1) Tanks. Each tank that is part of an UST system shall:

      1. (A) Be properly designed and constructed in accordance with a code of practice developed by a nationally recognized association or independent testing laboratory, unless the commissioner has posted on the department’s internet website that use of such code of practice is unacceptable. In addition, the commissioner may post codes of practice deemed acceptable on the department’s internet website; and(B) Be constructed of:

2. (i) Fiberglass-reinforced plastic;

   1. (ii) Steel coated with a factory applied suitable dielectric material approved by the manufacturer of such tank for the proposed use and is equipped with corrosion protection through the use of either:
   2. (I) Galvanic cathodic protection attached to the tank; or(II) An impressed current cathodic protection system that allows the owner or operator to determine whether such impressed current system is properly operating; or(iii) Steel and clad or jacketed with a non-corrodible material;
   3. (C) Be equipped with contact plates under all fill and gauge openings; and(D) In addition to compliance with subdivision (1)(A) to (1)(C), inclusive, of this subsection, for tanks installed on or after October 1, 2003, be a double-walled underground storage tank with secondary containment that can fully contain regulated substances leaked from the primary containment until the regulated substances are detected and removed and that can prevent the release of regulated substances from the tank at any time during the operational life of such tank; and (i) For tanks installed on or after October 1, 2003, but on or before August 5, 2025, continuously monitor the interstitial space of the tank of such UST system using inert gas, liquid, a vacuum, electronic monitoring, or mechanical monitoring; and(ii) For tanks installed after August 5, 2025, have continuous interstitial monitoring that monitors both primary containment and secondary containment, such that the inner and outer walls are continuously monitored using technology such as inert gas, liquid, or a vacuum, except that tanks installed after May 7, 2025 may have an electronic or mechanical system that does not continuously monitor both the inner and outer wall, such as a system utilizing a dry space with a sensor, provided that the tank and piping, whichever is applicable, shall meet the following conditions;

   4. (I) Be used for the storage of petroleum only;

      1. (II) Be constructed of double walled fiberglass-reinforced plastic or composite steel;
      2. (III) Have striker plates beneath each access point present since time of installation;
      3. (IV) Utilize non-metallic piping;

   5. (V) Have piping containment sumps and under dispenser containment sumps that are liquid tight and monitored;

      1. (VI) Pass an interstitial test that meets the requirements of the Petroleum Equipment Institute, Recommended Practice 1200-12 every 6 months until permanently closed;
      2. (VII) Not be located within an aquifer protection area or within 1,000 feet of a potable well, not including potable wells on the site where the tank is located; and(VIII) Conduct line leak testing, when required by section 22a-449(d)-104 of the UST regulations, every 6 months; and(E) For a hazardous substance UST:

3. (i) Comply with subparagraphs (A) to (D), inclusive, of this subdivision;

   1. (ii) Be equipped with external liners, including vaults, designed, constructed, and installed to:

   2. (I) Contain 100 percent of the capacity of the largest tank within its boundary;

      1. (II) Prevent the interference of precipitation or ground-water intrusion with the ability to fully contain or detect a release of regulated substances; and(III) Surround the tank completely so that it is capable of preventing lateral and vertical migration of regulated substances; and(iii) If installed before October 1, 2003, be double-walled, be designed, constructed, and installed to detect and fully contain a release from any portion of the primary containment system, including the inner wall of a tank, and have a secondary containment designed, constructed and installed to:

   3. (I) Continuously monitor for any liquid in the secondary containment;

      1. (II) Fully contain any liquid that is in such secondary containment until such liquid is detected and removed, except for brine being used for the purposes of interstitial monitoring; and(III) Prevent the release of any liquid outside of such secondary containment.

   4. (2) Piping. The owner or operator of an UST system shall ensure that all piping that routinely contains regulated substances and is part of such UST system is:

      1. (A) Properly designed and constructed in accordance with a code of practice developed by a nationally recognized association or independent testing laboratory, unless the commissioner has posted on the department’s internet website that use of such code of practice is unacceptable. In addition, the commissioner may post codes of practice deemed acceptable on the department’s internet website; and(B) Constructed of a non-corrodible material; or(C) Constructed of steel. If such piping is constructed of steel, such piping shall not come in contact with the ground or any water unless such piping is:

4. (i) Coated with a suitable factory applied dielectric material approved by the manufacturer of such piping for the proposed use; and(ii) Equipped with:

   1. (I) Galvanic cathodic protection attached to the piping; or(II) An impressed current cathodic protection system that allows the owner or operator to perform a structure to soil voltage test of such system to determine whether such system is properly operating; and(D) In addition to compliance with subparagraphs (A) and (B) or (C) of this subdivision:

5. (i) Except for repairs to piping pursuant to section 22a-449(d)-103(m)(2)(C) of the UST regulations, piping installed on or after October 1, 2003, shall:

   1. (I) Be double-walled with secondary containment that is capable of fully containing regulated substances released from primary containment and preventing the release of regulated substances from the piping at any time during the operational life of the UST system; and(II) Be equipped with interstitial monitoring, that, at a minimum, has sensors at both ends of the piping run or a vacuum that provides continuous interstitial monitoring; and(ii) All piping that conveys regulated substances under pressure shall be equipped with an automatic line leak detector capable of detecting the presence of a release of 3 gallons per hour at 10 pounds per square inch line pressure within 1 hour by restricting or shutting off the flow of regulated substances through piping.
   2. (E) The owner or operator shall ensure that all underground piping associated with a hazardous substance UST:

6. (i) Complies with the requirements of subparagraphs (A) to (D), inclusive, of this subdivision; and (ii) If such piping is installed before October 1, 2003, that such piping is equipped with secondary containment that is designed, constructed and installed to:

   1. (I) Allow proper monitoring for a release from such piping;

      1. (II) Fully contain any liquid that is in such secondary containment until such liquid is detected and removed, except for brine being used for the purposes of interstitial monitoring; and(III) Prevent the release of any liquid outside of such secondary containment.
   2. (3) Cathodic protection systems. All cathodic protection systems required by this subsection shall meet the specifications of the manufacturer of the component being protected and shall be capable of continuously providing corrosion protection.

   3. (4) Spill and overfill prevention equipment. The owner or operator of an UST system which receives transfers of 25 gallons or more of a regulated substance at one time shall ensure that such UST system complies with the following requirements:

      1. (A) Spill prevention equipment, such as a spill bucket, shall be capable of containing the amount of regulated substances in a transfer hose used to deliver regulated substances to an UST when such hose is detached from the fill pipe. Spill buckets that are part of an UST system shall be liquid tight. In no event shall such spill bucket be less than 5 gallons; and (B) Overfill prevention equipment shall:

7. (i) Automatically shut off flow into an UST when such tank is no more than 95 percent full; or (ii) Alert the transfer operator when an UST is no more than 90 percent full by triggering a high-level alarm that is both audible and visual.

   1. (5) Containment Sumps. The owner or operator of an UST system shall ensure that such UST system complies with the following requirements:

      1. (A) For an UST system installed on or after August 8, 2012:

8. (i) If the UST system includes a dispenser, it shall be equipped with under-dispenser containment sumps that comply with the requirements specified in subparagraph (C) of this subdivision; and(ii) No owner or operator shall install piping containment sumps unless such sump complies with the requirements specified in subparagraph (C) of this subdivision; and(B) For an UST system installed on or after May 7, 2025, no owner or operator shall use or operate such UST system, unless such UST system is equipped with piping containment sumps, and as applicable, under-dispenser containment sumps, that comply with the requirements specified in subparagraph (C) of this subdivision.

   1. (C) The owner or operator shall ensure that each under-dispenser containment sump or piping containment sump, as applicable:

9. (i) Prevents any liquids that may accumulate in such containment sump, including, but not limited to, liquid from the piping or pump, or from the dispenser, as applicable, from leaving the containment sump;

   1. (ii) Be capable of immediate visual inspection and provides immediate access to the components of such sump and the components contained therein; and(iii) Be equipped with an alarm or other device such as a sensor capable of immediately alerting the owner or operator whenever any liquid, including precipitation, is present in any such sump. The owner or operator shall ensure that any such alarm or other device:

   2. (I) operates as intended;

      1. (II) is not removed, disabled, or otherwise rendered inoperable; and (III) is located so that any liquid present in such sump can be detected.

   3. (6) Dispensers. An owner or operator shall ensure that all dispensers used with an UST system have the following:

      1. (A) A breakaway device that is compatible with the regulated substance being dispensed and that is installed in a vehicle fueling hose and separates when excessive pulling force is applied to the hose, including when a vehicle leaves the dispenser area with the nozzle from the fueling hose still in the vehicle fill pipe. When excessive pulling force is applied to such hose, a breakaway device shall prevent the flow of liquids from either section of the parted hose as well as protect the dispenser from damage;
      2. (B) A shear valve or crash valve that, when fueling occurs under pressure, automatically shuts off the flow of fuel to the dispenser in the event of a fire inside the dispenser or a severe impact to the dispenser; and(C) Except for dispensers located at a marina, a mechanism or a design for ensuring that a fuel dispensing hose is not on the ground when such hose is not in use.

10. (b) Installation and Testing Requirements.

    1. (1) Installation (A) The owner or operator shall ensure that every component of an UST system is installed in accordance with a code of practice developed by a nationally recognized association or independent testing laboratory and in accordance with the manufacturer’s instruction, unless the commissioner has posted on the department’s internet website that use of such code of practice is unacceptable. In addition, the commissioner may post codes of practice deemed acceptable on the department’s internet website.

       1. (B) The owner or operator shall ensure that for the installation of a tank or piping, all work listed in the manufacturer’s checklist or similar document from the manufacturer regarding installation has been completed and one of the following conditions is satisfied:

11. (i) The manufacturer of the tank or piping, as applicable, has certified the installer, in writing, to install such equipment; or(ii) The installation of such tank or piping has been inspected and approved, in writing, by a registered professional engineer licensed in the state of Connecticut and who has education and experience in UST tank and piping installation.

    1. (C) Within 30 days after completion of installation of a tank or piping as part of an UST system, the owner or operator shall submit to the commissioner a certification, on a form and in a manner prescribed by the commissioner, signed by the installation contractor, certifying that the installation has been carried out in accordance with clause (i) or (ii) of subparagraph (B) of this subdivision.

    2. (2) Installation Testing (A) (i) No owner or operator installing an UST system on or after August 8, 2012, shall place any regulated substances into such system until the owner or operator has conducted testing that demonstrates that there is no release or loss of any liquids from any component of such system.

       1. (ii) With the exception of a spill bucket, no owner or operator installing an UST system component on or after May 7, 2025 shall place any regulated substances or accept a delivery of regulated substances, as applicable, into such system until the owner or operator has conducted testing that demonstrates that there is no release or loss of any liquids from any component of such system.
       2. (iii) No owner or operator installing a spill bucket on or after May 7, 2025 shall accept a delivery of regulated substances into such system until the owner or operator has conducted testing that demonstrates that there is no release or loss of any liquids from the newly installed spill bucket.
       3. (B) The owner or operator of an UST system shall ensure that any test conducted to satisfy the requirements of subparagraph (A) of this subdivision shall be performed in accordance with the manufacturer’s guidelines and standards. If there are no manufacturer’s guidelines or standards, the owner or operator shall perform such tests in accordance with an applicable method specified in an industry code or engineering standard. If there are no applicable manufacturer’s guidelines or standards, industry codes, or engineering standards, the owner or operator shall perform all such tests using a test method that, before use, is approved in writing by a registered professional engineer licensed in the state of Connecticut. The owner or operator shall ensure that the person who performs the testing required by subparagraph (A) of this subdivision has the qualifications and experience to perform such testing, and the owner or operator shall maintain the results of such testing, which shall be made available for inspection by the commissioner.
       4. (C) Notwithstanding subparagraph (B) of this subdivision, an owner or operator shall not use a test method to comply with subparagraph (A) of this subdivision if the commissioner has posted on the department’s internet website that use of such test method is unacceptable. In addition, the commissioner may post test methods deemed acceptable on the department’s internet website.
    3. (3) Recordkeeping The owner or operator of an UST system shall maintain records demonstrating compliance with the requirements of this subsection in accordance with the requirements of section 22a-449(d)-114 of the UST regulations.
12. (c) Use of most stringent provision.If use of any manufacturer’s specifications and recommendations are required under this section and such specifications or recommendations are inconsistent with any provision of this section, the provision which imposes the most stringent and protective requirement shall be required.

(Effective July 28, 1994; Amended May 31, 2012; Amended December 1, 2021; Amended May 7, 2025)