DEEP: Underground Storage Tank Regulation Summary

Underground Storage Tank
Regulatory Summary

An Environmental Program Fact Sheet

The underground storage tank (UST) regulations (PDF) and the Amendments to the UST Regulations, May 31, 2012 (PDF) are preemptive in nature. Both at federal and State levels, the regulations are designed to prevent releases by closely monitoring petroleum and chemical storage and by imposing deadlines for removal of older USTs (and UST components) before they fail. All commercial USTs, regardless of volumetric capacity, fall under Sections 22a-449(d)-1 or 22a-449(d)-101 through 113 of the Regulations of Connecticut State Agencies (RCSA) if containing motor fuels, heating fuels, waste oils or CERCLA-listed chemicals.

Tank facilities, including integral piping, with ten percent or more of total volume below grade are considered "underground."  Since November 1985, it has been illegal to install any nonresidential UST component which is neither fiberglass-reinforced plastic (i.e., noncorrosive) nor which has a manufacturer-applied, anti-corrosive coating and cathodic protection. USTs and UST components which meet these criteria are said to meet new installation standards. As of October 1, 2003, these standards require that new UST installations be double-walled UST systems with double-walled tank(s) having a continuous 360 interstitial space monitored continuously via inert gas or liquid, vacuum monitoring, electronic monitoring or mechanical monitoring and double-walled piping.

USTs that do not meet new installation standards (e.g., bare-steel or concrete tanks and piping) could not be legally installed after November 1985 and cannot be used for longer than twenty (20) years (average life expectancy of fifteen years plus five) from legal date of installation. Furthermore, steel or concrete UST components can only be used up to twenty years, providing failure determination tests are conducted twelve years after installation and annually thereafter, and the UST systems are determined not to be leaking. Unprotected USTs greater than twenty years of age prior to September 1, 1989 were required to be taken out-of-service before that deadline.

UST systems had to be upgraded to meet new installation standards for protected tanks and piping and equipped with spill and overfill protection prior to December 22, 1998.  If not so upgraded, USTs had to be taken out-of-service and permanently closed prior to December 22, 1998. 

All tank closures (excavation or abandonment in-place by cleaning and filling with a solid, inert material, usually dry sand or concrete) must be accompanied by a closure report which includes sampling of soils (and potentially groundwater) to verify that petroleum/CERCLA chemical releases have not occurred. If contamination is discovered, those releases must be reported immediately to the CT DEEP, and clean-up must be conducted to bring levels of contaminants below current departmental standards, as defined in the Remediation Standard Regulations (Section 22a-133(k)-1 through 22a-133(k)-3 of RCSA).

Daily inventories, weekly and monthly reconciliations of those readings must be conducted for USTs containing motor fuels and waste oils. Daily losses or gains exceeding one half of one percent of the total volumetric capacity of the tank system are considered "abnormal" and must be investigated and reported as potential leaks.

UST owners/operators of heating oil USTs need only conduct annual failure determination tests at the end of UST facility life expectancy to comply with state leak detection requirements. Options for leak detection, other than annual failure determination testing, include automatic tank gauging systems, interstitial monitoring (in the case of double-walled tanks), monthly sampling of groundwater monitoring wells or monthly monitoring of "vapor sniffing" wells.  Piping also must be periodically tested for integrity.

All test results, closures, new installations or general changes in status of UST systems or facilities MUST be reported to the Storage Tank Enforcement Unit of CT DEEP on prescribed DEP-UST-NOT-001 Notification Forms (Word, PDF, Instructions). Such notification is a federal and state legal requirement.  Any person who owns an UST system that stores or has stored petroleum or hazardous substances must notify the DEEP by submitting the form. 

The Notice of Intent to Amend was published on June 22, 2010.  A public hearing was held on July 28, 2010 regarding the proposed changes to the UST regulations.  Both oral and written testimony and comments were received.  A Statement of Reasons is being prepared by the Hearing Officer. 

For further information contact the Storage Tank Enforcement Unit at (860) 424-3374 or write to:

Department of Energy and Environmental Protection
Bureau of Materials Management and Compliance Assurance
Emergency Response and Spill Prevention Division
Storage Tank Enforcement Unit
79 Elm Street
Hartford, CT  06106-5127

Content Last Updated November 9, 2011