Storage Tanks in Connecticut: DEEP Registration, Training, and Fees

Connecticut’s storage tank regulations are administered by the Department of Energy and Environmental Protection (DEEP), which sets rules for installing, monitoring, insuring, and closing underground and aboveground tanks that hold petroleum or hazardous liquids. If you own a regulated tank, you file a notification with DEEP, pay an annual fee, keep trained operators on staff, carry financial responsibility coverage, watch for leaks every 30 days, and follow a strict script if you ever spill or close a tank. Small residential heating oil tanks serving four or fewer dwelling units sit outside the program entirely.

Which Tanks DEEP Regulates

The underground storage tank (UST) program covers any system where at least 10 percent of the tank’s volume sits below ground and the buried portion is not fully visible for inspection. “Nonresidential” reaches commercial, industrial, institutional, and public buildings, along with hotels, hospitals, nursing homes, correctional facilities, and residential buildings with more than four living units.¹ Farm tanks of 1,100 gallons or less used for motor fuel that is not resold are also in.

Residential underground heating oil tanks serving four or fewer dwelling units are excluded from the definition of a “UST system” under RCSA 22a-449(d)-1 and are not regulated by DEEP.² The exemption ends as soon as a tank serves a fifth unit. Homeowners with a residential heating oil tank can still face cleanup obligations under Connecticut’s general environmental statutes if the tank leaks, but the registration, testing, operator, and financial assurance rules described below don’t apply.

The program runs on two sets of rules: RCSA Section 22a-449(d)-1 for nonresidential petroleum USTs, and RCSA Sections 22a-449(d)-101 through 22a-449(d)-114 for the broader technical standards on federally regulated systems.³ Connecticut generally tracks federal EPA standards but layers stricter requirements on top in some areas, including closure sampling and operator training. When state and federal rules conflict, the more protective one wins.

Registering a Tank and Paying the Annual Fee

Every regulated UST must be registered with DEEP using the Notification for Underground Storage Tanks form (DEEP-UST-NOT-001), submitted through the ezFile portal.⁴ The form identifies the facility, the tank’s capacity and contents, the tank and piping construction materials, the leak detection method, the legal owner, and the person responsible for day-to-day operation.

Once registered, the information has to stay current. Owners must update the notification within 30 days of any change, including new installations, ownership transfers, or a switch in the substance stored.⁴ Test results and closures also go on the notification form.⁵

Installing a new regulated UST carries a one-time fee of $100 per tank. Every active or temporarily out-of-service tank then incurs a $100 annual fee per tank, payable through ezFile between August 1 and October 10 each year.⁴

Operator Training

Every UST facility must have at least one designated Class A, Class B, and Class C operator, and each designation must be submitted to DEEP through ezFile.⁶ The three classes reflect different levels of responsibility.

The Class A operator has primary regulatory responsibility, managing resources and personnel to keep the system in compliance. The Class B operator handles day-to-day operations, maintenance, and recordkeeping in the field, and a single Class B operator can cover multiple facilities. The Class C operator is an on-site employee who responds first to alarms, spills, and releases, and knows when to escalate. Class C operators are trained by the certified Class B operator at the same facility.

Falling behind on training is not a minor housekeeping problem. DEEP can shut down (or “red-tag”) a facility until operator training compliance is restored.⁶ Under federal rules, once a facility is found out of compliance, Class A and Class B operators have to be retrained within 30 days.

Leak Detection and 30-Day Walkthroughs

Federal rules require walkthrough inspections of spill prevention and release detection equipment at least once every 30 days, with containment sumps and handheld release detection devices checked at least annually.⁷ The 30-day phrasing replaced “monthly” in federal guidance because “monthly” was sometimes stretched past 30 calendar days. Pressurized piping requires an automatic line leak detector that shuts off flow, restricts flow, or triggers an alarm, and piping installed or replaced after April 11, 2016 must also use secondary containment with interstitial monitoring.

Warning signs of a suspected release include inventory discrepancies between fuel delivered and fuel dispensed, alarms from automatic tank gauging, unexpected water in a tank, and visible spills during delivery.⁸ Any of those triggers an obligation to investigate, and a confirmed release must be reported to DEEP.

Financial Responsibility After the Cleanup Fund Ended

Connecticut’s UST Petroleum Clean-up Program ended on June 23, 2025. Remaining appropriations were transferred to the general fund, and pending applications were cancelled.⁹ Tank owners can no longer rely on the state fund as a backstop. Every owner must now carry an independent financial responsibility instrument, and the deadline to have one in place was August 5, 2025.¹⁰

RCSA Section 22a-449(d)-109 lists the acceptable mechanisms. Non-government owners can use a financial test of self-insurance, a corporate guarantee, pollution liability insurance or risk retention group coverage, a surety bond, a letter of credit, a trust fund, or a combination of these. Local governments have several additional options, including a bond rating test, a local government financial test, and a local government fund.¹⁰

Coverage Amounts

Federal minimums apply. Petroleum marketers and any operation handling more than 10,000 gallons per month must carry at least $1 million per occurrence. Other petroleum UST owners need at least $500,000 per occurrence. Annual aggregate coverage must be at least $1 million for owners with 1 to 100 tanks and $2 million for owners with 101 or more tanks.¹¹ Self-insurance through the financial test requires tangible net worth of at least $10 million and at least ten times the aggregate coverage obligation.¹² For most small and mid-size owners, that leaves commercial pollution liability insurance as the practical choice.

Reporting a Spill or Release

Connecticut General Statutes Section 22a-450 requires anyone who causes or discovers a spill, discharge, or uncontrolled loss of petroleum, chemical liquids, or hazardous waste to report it immediately to DEEP’s Emergency Response Unit at 860-424-3338 or 1-866-DEP-SPIL, staffed 24 hours a day.¹³

Under RCSA Section 22a-450-4, the initial report has to reach DEEP within one hour of discovery. For certain lower-risk releases that have already been fully contained, the window is two hours.¹⁴ The owner must also act immediately, using properly trained personnel, to contain and remove the released material. That is one of the tightest reporting windows in the country.

Failing to report carries a fine of up to $1,000 for the individual and up to $5,000 for the employer. For gasoline releases, those figures rise to $5,000 and $10,000.¹⁵ Those penalties are separate from any cleanup liability.

Closing a Tank

Permanently closing a UST starts with written notification to DEEP at least 30 days before any physical work begins.¹⁶ The 30-day window lets DEEP coordinate oversight. RCSA Section 22a-449(d)-107 then sets out the procedure.

The person doing the closure needs a 40-hour Hazardous Waste Operations and Emergency Response (HAZWOPER) certification under 29 CFR 1910.120, a passing score on the International Code Council Decommissioning Exam U2, and current annual HAZWOPER refresher training.¹⁷ This is not general-contractor work.

After the tank is emptied, cleaned of all liquids and sludge, and either removed or filled with inert material, a qualified sampler with at least three years of environmental sampling experience must conduct a site assessment within five days. Samples have to cover all sides and the bottom of the excavation, any visibly stained areas, spots around holes or perforations in the removed tank, and the locations of spill buckets, containment sumps, or dispensers. Piping requires at least one sample at every 10-foot interval where contamination is most likely, and shorter runs still require at least one sample. All samples must be analyzed by a laboratory certified by the Connecticut Department of Public Health.¹⁷

Once the physical work and lab analysis are complete, the owner submits a separate closure notification through ezFile to remove the tank from DEEP’s active inventory.¹⁶ If sampling turns up contamination above applicable standards, the site moves into corrective action, which can add substantial time and cost.

Aboveground Tanks

Aboveground storage tanks in Connecticut are governed primarily by federal Spill Prevention, Control, and Countermeasure (SPCC) rules at 40 CFR Part 112. A facility needs an SPCC plan once its total aboveground oil storage capacity exceeds 1,320 gallons, with containers under 55 gallons excluded from the calculation.¹⁸ Secondary containment must hold at least 110 percent of the tank’s capacity. Facilities storing 10,000 pounds or more of substances like gasoline, diesel, propane, or kerosene may also face reporting under the Emergency Planning and Community Right-to-Know Act (EPCRA). SPCC rules originate with EPA, but DEEP can still enforce state environmental statutes against any AST owner whose tank causes a release.

Penalties for Storage Tank Violations

Beyond the spill-reporting fines, Connecticut imposes civil penalties under Section 22a-6b for storage tank violations, in two tiers.¹⁹ Registration and reporting failures, including missed notifications, unfiled reports, and unregistered tanks, carry up to $1,000 for the initial violation plus up to $100 for each day it continues. Discharge and contamination violations, including unauthorized discharges, operating a tank in violation of a regulation or permit, and maintaining conditions that cause pollution, carry up to $25,000 for each day the violation continues.

These are civil penalties, so DEEP can pursue them administratively without going through the criminal courts. At $25,000 per day, a contamination violation left unaddressed even for a few weeks can generate a bill larger than the underlying compliance work would have cost. DEEP also has authority to issue orders requiring immediate corrective action, and violating a final DEEP order carries additional penalties stacked on top of the original violation.

1
Connecticut eRegulations. Connecticut Code 22a-449(d)-1 – Control of the Nonresidential Underground Storage and Handling of Oil and Petroleum Liquids
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Connecticut Department of Energy & Environmental Protection. Underground Storage Tanks Serving Five or More Residential Units
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Connecticut Department of Energy & Environmental Protection. Underground Storage Tanks
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Connecticut Department of Energy & Environmental Protection. Underground Storage Tank Program Fact Sheet
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Connecticut Department of Energy & Environmental Protection. Underground Storage Tank Regulation Summary
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Connecticut Department of Energy & Environmental Protection. UST Operator Training
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U.S. Environmental Protection Agency. Release Detection for Underground Storage Tanks – Introduction
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U.S. Environmental Protection Agency. Suspected Release Investigation, Confirmation of Releases, and Closure
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Connecticut Department of Energy & Environmental Protection. UST Clean-Up
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Connecticut eRegulations. Connecticut Code 22a-449(d)-109 – Financial Responsibility
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eCFR. 40 CFR 280.93 – Amount and Scope of Required Financial Responsibility
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eCFR. 40 CFR 280.95 – Financial Test of Self-Insurance
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Connecticut Department of Energy & Environmental Protection. Reporting Requirements for Spill Incidents
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Connecticut eRegulations. Connecticut Code 22a-450-4 – Reporting Requirements
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FindLaw. Connecticut Code 22a-450 – Report of Discharge, Spill, Loss, Seepage or Filtration
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Connecticut Department of Energy and Environmental Protection. Notification of Scheduled Permanent Closure of Underground Storage Tanks
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Connecticut eRegulations. Connecticut Code 22a-449(d)-107 – Closure of an UST System
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Connecticut Department of Energy & Environmental Protection. Petroleum Storage and Dispensing
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Justia Law. Connecticut General Statutes 22a-6b – Imposition of Civil Penalties