Environmental · Connecticut cleanup rules
Connecticut's Release Based Cleanup Regulations, explained.
Since March 1, 2026, what starts the clock on a contaminated site in Connecticut isn't selling the property. It's finding the contamination. Here's how the new rules work, from the Licensed Environmental Professionals who work under them.
What changed
Finding contamination now starts the clock.
Under the Transfer Act, cleanup obligations were triggered when certain properties changed hands. Under the Release Based Cleanup Regulations (RBCRs), in effect since March 1, 2026, they're triggered by the "discovery" of a release: laboratory data showing contamination in soil, groundwater or soil vapor, or several lines of evidence pointing to it. That includes old contamination, even if the state already knew about it.
The RBCRs replaced the Remediation Standard Regulations (RSRs), and the cleanup standards came with them: the numbers a site has to meet are the ones that have been in place since 1996, with some additions. What changed is the process around them. Releases now have reporting deadlines, they're assigned to "tiers" based on risk, and each one carries an annual fee to the Connecticut Department of Energy and Environmental Protection (DEEP) until a Licensed Environmental Professional (LEP), the person the state authorizes to sign off on a cleanup, verifies it's closed.
Under the new rules, the order you do things in can decide how a release is tiered and what it costs. We plan that order before anyone takes a sample.
Our LEPs
The LEPs behind this guidance.
This page is built on the advice Tory has given owners, utilities and engineers since before the new rules took effect.
Victoria Man, LEP
Tory has led ZUVIC's environmental practice since 2009 and has advised owners, utilities and engineers on the new rules since before they took effect.
Daniel Pinho, LEP
Dan takes commercial, industrial and utility sites from first sample to final report, from Eversource's decommissioned substations to tank closures across Connecticut.
Discovery
Not every detection has to be reported.
Any detected level of a contaminant counts as discovering a release. Whether you then have to report it depends on what was found and how much. The regulations carve out several cases:
- In soil, a substance other than a volatile organic compound or PFAS at no more than 25 percent of its cleanup criterion is treated as incidental: no further requirements.
- Up to 50 percent of the criterion is also incidental if the source is known and two more soil samples confirm it.
- Metals at naturally occurring levels aren't a release. The regulations set the test: how many samples, and how the results compare to DEEP's background ranges.
- Some sources are excluded outright, such as utility poles and landscaping timbers still in use, automotive exhaust, and fertilizer or pesticides applied according to their labels.
Getting this sorting right is often the difference between a report, a tier and a fee, and none of the three.
Reporting deadlines
Three kinds of release, three clocks.
New spills
"Emergent reportable releases" require immediate action.
- 10 gallons or more of oil or petroleum
- 3 gallons or 20 pounds or more of other materials
- Smaller spills are still reported to DEEP under the spill regulations
Significant existing releases
Report within 72 hours of discovery, or 24 hours if a drinking water well is affected. Immediate actions start right away.
- A public or private drinking water well is contaminated
- Groundwater above the groundwater protection criteria within 500 feet of a drinking water well
- Soil within two feet of the surface far above the direct exposure criteria
- Volatile contamination in groundwater within 15 feet of a building, at 10 times the volatilization criteria or more
- Groundwater far above the surface water protection criteria, or free product, close to surface water
- Followed by immediate actions, plans due within 30 to 90 days depending on the type of release, and an LEP-verified Immediate Action Report
Other existing releases
Everything else that has to be reported, on a longer clock.
- Within 120 days: more than twice the cleanup criteria (for petroleum, if more than 2 cubic yards of soil are affected), or free product at least 1/8 inch thick
- Within 365 days: lower concentrations that still require reporting
- No report at all if the release is characterized, cleaned up and closed with an LEP-verified Release Remediation Closure Report before the deadline
Tiers and fees
A release that isn't closed within a year gets a tier.
Each tier has its own oversight, deadline and fee. A release has to be closed or moved to a lower tier by the deadline. The fee is paid when the tier is assigned and every year after, rising 10 percent for each year the release stays in its tier. Related releases can be grouped under a single fee.
- Tier 1A
- DEEP oversight · 1 year · $3,000
- Tier 1B
- LEP oversight · 2 years · $1,500
- Tier 2
- LEP oversight · 4 years · $1,000
- Tier 3
- Natural attenuation · 5 years · $500
A release lands in Tier 1A, under DEEP's direct oversight, when basic work isn't done yet: the drinking water receptor survey, the vapor intrusion survey, the ecological risk screening, the required immediate actions. Doing that work first is the simplest way to keep a release out of the most expensive tier.
Sites already in a program
Already in the Transfer Act program? You may not have to switch.
Sites already in the Transfer Act's Property Transfer Program can generally stay there, and DEEP's guidance says new findings at those sites are handled in that program rather than reported under the RBCRs. For some owners, staying put is the cheapest path: no new schedule and no new fees.
The voluntary remediation programs changed too. One was discontinued and another was replaced by a new site-wide version with a filing fee of its own. For a single release, entering the new rules at a lower tier can cost less than refiling. We run that comparison property by property before recommending a move.
Construction
Building on a site? Plan before you sample.
Under the old rules, contractors routinely tested stockpiled soil and decided from the results whether to reuse it or haul it away. Now, any sample taken during design or construction, including waste characterization and dewatering tests, can discover a release. DEEP has been clear in its training sessions: contamination found during construction is characterized and, where required, reported and tiered like any other release.
- Decide what you'll do with a result before you take the sample. Every sample should have a purpose and a plan.
- Where soil can stay on site and shows no sign of contamination, it may not need testing at all. Soil that looks, smells or is known to come from a contaminated area is set aside and evaluated, not reused.
- If soil has to leave the site, sample it in place before it's dug, so any result can be tied to a location.
- Update the drinking water and vapor intrusion surveys before sampling, so a discovered release doesn't land in Tier 1A.
- Know the ways to reach compliance without removing everything: soil beneath buildings or clean fill and pavement can be made "inaccessible," and engineered controls are allowed. Most of these need an environmental use restriction recorded on the land records, with inspections and reporting for as long as it's in place.
Our work under the new rules
Representative work.
A substation closed under the new rules
For Eversource, ZUVIC took a decommissioned substation from Phase I through cleanup, four quarters of groundwater sampling and, in August 2026, an LEP verification of closure under Connecticut's new Release Based Cleanup Regulations.
A campus, property by property
For a university with properties in the Transfer Act program and both voluntary programs, ZUVIC compared each property's options: stay in its current program, refile under the new voluntary program, or move into the new rules. Several properties stayed where they were; for others, entering the new rules at a lower tier cost less than refiling.
Utility construction without surprises
For a water utility's treatment plant and reservoir projects, ZUVIC set out how excavated soil would be handled, where it could be reused, and when and where to sample, so construction wouldn't discover releases nobody had planned for.
FAQ
Questions we hear.
What are Connecticut's Release Based Cleanup Regulations?
The state's rules for reporting and cleaning up contamination, in effect since March 1, 2026. They tie obligations to the discovery of a release instead of the sale of a property, set reporting deadlines, assign releases to tiers based on risk, and charge an annual fee until an LEP verifies the release is closed.
Did the cleanup standards change?
Mostly not. The new regulations carried forward the cleanup standards of the Remediation Standard Regulations, which date to 1996, and added some options, including new ways to demonstrate compliance and specific pathways for home heating oil, PFAS and road salt. The bigger change is the process: reporting, tiers, deadlines and fees.
Does every lab detection have to be reported?
No. Any detection counts as discovering a release, but low soil concentrations of most substances are treated as incidental, naturally occurring metals aren't a release, and some sources are excluded. Releases that must be reported have deadlines of 72 hours, 120 days or 365 days depending on what was found, and some can be closed before the deadline so no report is needed.
My property is already in the Transfer Act program. Do I have to report under the new rules?
Generally not. DEEP's guidance says findings at a site in the Property Transfer Program are handled within that program. Whether to stay or move into the new rules depends on the site, and for some properties moving costs less. An LEP can compare the two for your site.
What does it cost?
State fees depend on the tier: $3,000 for Tier 1A, $1,500 for Tier 1B, $1,000 for Tier 2 and $500 for Tier 3, paid when the tier is assigned and every year after, rising 10 percent for each year in the tier. Investigation and cleanup costs are separate and depend on the site.
We're about to excavate. Should we test the soil?
Only with a plan for the result. Any detection during construction can discover a release, and DEEP expects those releases to be characterized like any other. Soil that stays on site and shows no sign of contamination may not need testing; soil leaving the site should be sampled in place before it's dug. Talk to an LEP before the sampling plan is set.
Next step
Call before you sample.
Twenty minutes with an LEP is usually enough to tell you which rules apply to your site and what to do first.
Or see our environmental services. We reply the same business day.
ZUVIC Inc. is a civil and environmental engineering firm in Rocky Hill, Connecticut, with two Licensed Environmental Professionals on staff. This page summarizes Connecticut's Release Based Cleanup Regulations as of October 2026. DEEP continues to issue guidance on the program; it is general information, not advice for a specific site.