Connecticut rulebook
The environmental and land-use rules Connecticut projects meet, with status and the official citation. Federal rules that reach Connecticut projects are included and marked Federal. Subscribers see who each rule covers, what it requires, how long it takes, the penalties and every date ahead.
Air, energy and climate
Air permits for new sources and generators
Medium impact
Requires air permits for new emission units above set thresholds. Emergency generators, such as data centre backups, can usually run under a permit-by-rule with hour or fuel limits instead.
C.G.S. 22a-174; R.C.S.A. 22a-174-3a, -3b, -3c · CT DEEP · checked Oct 4, 2026
Area designations under the 2024 annual fine-particle (PM2.5) standard
High impactFederalProposed
EPA is deciding which areas fail the 2024 annual PM2.5 standard of 9.0 micrograms per cubic meter. Final designations are due by February 6, 2027 under a court order. Pennsylvania recommended nonattainment for eight counties; EPA's letter to New Jersey names four South Jersey counties in the multi-state Philadelphia area. EPA told New York and Connecticut they have no affected monitors.
Clean Air Act § 107(d), 42 U.S.C. 7407(d); 91 Fed. Reg. 63516 (Oct. 6, 2026); Docket EPA-HQ-OAR-2024-0078 · US EPA · checked Oct 7, 2026
Federal tax credit deadlines for wind and solar projects
High impactFederal
Under the 2025 budget law, wind and solar projects lose the clean electricity credits unless construction began by July 4, 2026 or they are placed in service by December 31, 2027. A federal court vacated the IRS notice limiting how construction can be shown (June 6, 2026), restoring the 5% safe harbor for now.
26 U.S.C. 45Y, 48E as amended by P.L. 119-21 · US Treasury and IRS · checked Oct 6, 2026
Power plant CO2 cap update (RGGI, from 2027)
Medium impactProposed
DEEP's proposed amendments to Connecticut's RGGI rule would tighten the carbon dioxide cap on fossil fuel-fired power plants of 25 MW or more from 1 January 2027, to 61 to 90% below 2026 levels by 2037, expand the cost containment reserve, drop set-aside accounts and the emissions containment reserve, and repeal the offset project rule.
C.G.S. 22a-174; R.C.S.A. 22a-174-31 and 22a-174-31a (proposed amendments, PR2025-028) · CT DEEP · checked Oct 6, 2026
Siting Council approval for energy and telecom
High impact
The Siting Council approves power plants, storage, transmission lines, pipelines and telecom towers in place of most local zoning and wetlands approvals. Qualifying smaller projects can use a petition for declaratory ruling.
C.G.S. 16-50g to 16-50ll; Public Act 26-127 · Connecticut Siting Council · checked Oct 6, 2026
Building operations
2026 State Building Code (pending)
Low impactChanges pending
Would update Connecticut's building code to the 2024 international codes. Lawmakers rejected it without prejudice in April 2026, so the 2022 code stays in force until a revised version is approved.
C.G.S. 29-252, 29-252b; PA 26-58; 2026 State Building Code · DAS Office of the State Building Inspector · checked Oct 4, 2026
Asbestos notice before demolition and renovation
Medium impactFederal
Before demolishing a commercial, industrial or multifamily building, and before renovations disturbing more than set amounts of regulated asbestos, the owner or operator must inspect for asbestos and notify the delegated state agency or EPA at least 10 working days in advance.
40 CFR 61.145 · US EPA, with delegated state agencies · checked Oct 6, 2026
Lead-safe renovation of pre-1978 housing and child-occupied buildings
Low impactFederal
Renovation, repair and painting that disturbs more than 6 square feet inside or 20 square feet outside in housing or child-occupied facilities built before 1978 must be done by EPA-certified firms using lead-safe work practices, with pre-renovation notice to occupants.
40 CFR Part 745, Subpart E · US EPA · checked Oct 6, 2026
Underground and aboveground storage tank rules
Low impact
DEEP regulates nonresidential underground tanks for fuel, heating oil, used oil and hazardous substances: design, registration, leak detection, release reporting, closure and, for petroleum, financial responsibility. Large aboveground oil storage needs a federal spill plan.
C.G.S. 22a-449(d); R.C.S.A. 22a-449(d)-1, -101 to -114 · CT DEEP · checked Oct 5, 2026
Cleanup and contamination
Brownfield liability relief program (BRRP)
Low impact
Gives buyers and innocent owners of brownfields protection from state and third-party liability for existing contamination, in return for investigating and cleaning up the site on a set schedule and paying a fee.
C.G.S. 32-760, 32-769 · CT DECD; CT DEEP · checked Oct 4, 2026
Clean fill, demolition waste and soil reuse
Medium impact
Connecticut's solid waste law decides what a site may keep as fill and what must go to a permitted facility. Polluted soil can be reused only under the release-based cleanup rules.
C.G.S. 22a-207, 22a-208a, 22a-209f; R.C.S.A. 22a-209-1 · CT DEEP · checked Oct 5, 2026
Oil spill prevention plans for fuel storage (SPCC)
Low impactFederal
Facilities with more than 1,320 gallons of aboveground oil storage (counting containers of 55 gallons or more), or 42,000 gallons underground, that could reach waters must prepare and follow a Spill Prevention, Control and Countermeasure plan.
40 CFR Part 112 · US EPA · checked Oct 6, 2026
PFAS: water action levels and product bans
Low impact
Sets state drinking water action levels for PFAS, treats PFAS releases of any quantity as reportable, and requires notice and labels now, then a 2028 sales ban, for 12 product types with intentionally added PFAS.
C.G.S. 22a-903c; DPH PFAS action levels · CT DPH; CT DEEP · checked Oct 4, 2026
PFOA and PFOS as federal hazardous substances
High impactFederal
Since July 8, 2024, PFOA and PFOS are CERCLA hazardous substances: releases of a pound or more in 24 hours must be reported, and owners can face federal cleanup liability. EPA kept the designation (September 2025) and the D.C. Circuit upheld it on August 18, 2026.
40 CFR 302.4; 89 FR 39124 · US EPA · checked Oct 6, 2026
Property Transfer Act, legacy sites only
High impact
The old rule that made property sales trigger cleanup. It no longer applies to new deals, but sites already in the program must still finish or switch to the release-based program.
C.G.S. 22a-134 to 22a-134e; Public Acts 25-6 and 25-54 · CT DEEP · checked Oct 4, 2026
Release-based cleanup program
High impact
Replaced the Transfer Act on 1 March 2026. Whoever creates or maintains a release of oil, petroleum or hazardous substances must report it to DEEP on a set clock, then investigate and clean it up.
C.G.S. 22a-134pp to 22a-134yy; R.C.S.A. 22a-134tt-1 to -13 · CT DEEP · checked Oct 4, 2026
Remediation standards for soil and groundwater
Medium impact
Sets the soil and groundwater cleanup numbers used in Connecticut cleanups, based on intended use. Since 1 March 2026 the standards sit in the release-based cleanup regulations.
C.G.S. 22a-133k; R.C.S.A. 22a-134tt (was 22a-133k-1 to -3) · CT DEEP · checked Oct 4, 2026
Superfund liability and the buyer’s defence (All Appropriate Inquiries)
High impactFederal
Owners of contaminated property can be liable for federal cleanup costs. A buyer can protect itself as a bona fide prospective purchaser by completing All Appropriate Inquiries (a Phase I to ASTM E1527-21) before acquisition and meeting continuing obligations afterwards.
42 U.S.C. 9601(40), 9607(r); 40 CFR Part 312 · US EPA · checked Oct 6, 2026
Environmental review and justice
Endangered species review (NDDB)
Medium impactChanges pending
Screens projects for harm to state-listed endangered and threatened species. State permit applicants whose sites fall in a shaded area on DEEP's Natural Diversity Data Base (NDDB) maps must request a DEEP review.
C.G.S. 26-303 to 26-315 · CT DEEP · checked Oct 6, 2026
Environmental intervention and historic resources review
Medium impact
Lets any person sue, or intervene in a permit or land-use proceeding, to stop unreasonable harm to air, water, other natural resources or listed historic structures. Approval is barred if a feasible and prudent alternative exists.
C.G.S. 22a-14 to 22a-20 (esp. 22a-19, 22a-19a) · Reviewing agency; Superior Court; SHPO · checked Oct 4, 2026
Environmental justice public participation law
Medium impactChanges pending
Requires extra community outreach before permits for new or expanded facilities of the listed types (affecting facilities) in environmental justice communities. A power to deny permits over cumulative impacts starts only once DEEP adopts regulations.
C.G.S. 22a-20a (as amended by PA 23-202) · CT DEEP; Connecticut Siting Council · checked Oct 4, 2026
Federal endangered species review, including tree-clearing limits for bats
High impactFederal
Projects with a federal permit or funding need Fish and Wildlife Service consultation where listed species may be affected, and no project may “take” a listed species. The northern long-eared bat (endangered since March 31, 2023) limits tree clearing across all four states; the tricolored bat is proposed for listing.
16 U.S.C. 1536, 1538, 1539; 50 CFR Parts 17 and 402 · US Fish and Wildlife Service · checked Oct 6, 2026
Federal environmental review (NEPA)
High impactFederal
A federal permit, licence or funding decision triggers review under NEPA. CEQ’s regulations were removed (final January 8, 2026), so each agency now follows its own procedures, and the statute sets page limits and deadlines: one year for an environmental assessment and two years for an impact statement.
42 U.S.C. 4321 et seq.; 42 U.S.C. 4336a · Each federal agency; Council on Environmental Quality (guidance) · checked Oct 6, 2026
Historic preservation review for federal permits and funding (Section 106)
Medium impactFederal
Before a federal permit, licence or funding decision, the agency must consider effects on historic properties and consult the State Historic Preservation Office. The Advisory Council voted on July 24, 2026 to propose a major overhaul; the proposal is not yet published.
54 U.S.C. 306108; 36 CFR Part 800 · Advisory Council on Historic Preservation; State Historic Preservation Offices · checked Oct 6, 2026
State environmental review (CEPA)
Medium impact
Connecticut's environmental review law. State agencies must assess actions they carry out or fund that could have a major environmental impact, which can pull in private projects backed by state grants or loans.
C.G.S. 22a-1 to 22a-1h; R.C.S.A. 22a-1a · Sponsoring state agency; OPM · checked Oct 4, 2026
Flooding and the coast
Coastal consistency review of federal permits
Medium impactFederal
In a state’s coastal zone, an applicant for a federal permit must certify that the project is consistent with the state’s coastal management program, and the state can object. NJ, NY, CT and PA (Delaware Estuary and Lake Erie) all have approved programs.
16 U.S.C. 1456(c); 15 CFR Part 930 · NOAA; state coastal programs (NJDEP, NY DOS, CT DEEP, PA DEP) · checked Oct 6, 2026
Coastal permits for tidal wetlands, docks and fill
High impact
DEEP authorization is needed for structures, dredging, fill and obstructions in coastal waters below the coastal jurisdiction line, and for most work in tidal wetlands.
C.G.S. 22a-28 to 22a-35; 22a-359 to 22a-363h · CT DEEP · checked Oct 4, 2026
Coastal site plan review
Medium impact
Town land-use boards check that projects in the coastal boundary are consistent with state coastal policies and limit harm to coastal resources and water-dependent uses.
C.G.S. 22a-105 to 22a-109 · Town land-use commissions; CT DEEP · checked Oct 6, 2026
Federal flood map and floodplain building rules (NFIP)
High impactFederal
Towns in the National Flood Insurance Program must permit development in mapped flood zones and require new and substantially improved buildings to be elevated or floodproofed to the base flood elevation. A preliminary map change opens a 90-day appeal period.
42 U.S.C. 4001 et seq.; 44 CFR 59.1, 60.3; 44 CFR Part 67 · FEMA; municipal floodplain administrators · checked Oct 6, 2026
Flood management certification for state-funded work
Medium impact
State agency actions in or affecting a floodplain, including state or federal grants or loans for projects, need DEEP flood management certification. A separate DEEP permit covers work beyond stream channel encroachment lines.
C.G.S. 25-68b to 25-68h; 22a-342 to 22a-349a · CT DEEP · checked Oct 4, 2026
Work in navigable waters: piers, bulkheads and dredging (Section 10)
Medium impactFederal
Building structures in, over or under navigable waters, or dredging them, needs an Army Corps permit under Section 10 of the Rivers and Harbors Act, often together with a Section 404 permit.
33 U.S.C. 403; 33 CFR Part 322 · US Army Corps of Engineers · checked Oct 6, 2026
Land use and housing
2025 housing law: parking and middle housing
Low impact
Eases local barriers to housing. It limits parking-based denials, requires towns to allow 2-to-9-unit middle housing on commercial and mixed-use lots with summary review, and requires housing growth plans.
Public Act 25-1 (Nov. 2025 Sp. Sess., HB 8002) · OPM; Councils of Governments; town zoning · checked Oct 4, 2026
Affordable housing appeals (8-30g)
Medium impact
Helps affordable housing get approved in towns with little of it. If the town denies or burdens the project, the town must justify that decision in court.
C.G.S. 8-30g (as amended by PA 25-1) · Town land-use commissions; Superior Court · checked Oct 4, 2026
Connecticut River Gateway conservation zone
Medium impact
Protects the scenic lower Connecticut River by setting minimum standards that eight towns' zoning must meet for land in the Gateway Conservation Zone, which runs from ridge top to ridge top along the river.
C.G.S. 25-102a to 25-102m · Connecticut River Gateway Commission · checked Oct 4, 2026
Data centre tax incentive program
Low impact
Offers sales, use and property tax exemptions, including on electricity, to large data centres. There is no separate state siting law; normal zoning, DEEP permits and Siting Council rules apply.
C.G.S. 32-286 (Public Act 21-1) · CT DECD · checked Oct 4, 2026
FAA notice for tall structures and cranes
Medium impactFederal
Structures and construction cranes over 200 feet, or lower near airports, need notice to the FAA at least 45 days before construction starts. The FAA decides whether the structure is a hazard and may require marking and lighting.
49 U.S.C. 44718; 14 CFR Part 77 · Federal Aviation Administration · checked Oct 6, 2026
HUD environmental review and flood standard for assisted housing
Medium impactFederalChanges pending
Housing using HUD funds needs an environmental review before funds are committed, and new or substantially improved HUD-assisted buildings must meet the Federal Flood Risk Management Standard adopted in 2024. HUD proposed on July 10, 2026 to rescind that standard; comments closed September 8, 2026.
24 CFR Parts 50, 55 and 58 · US Department of Housing and Urban Development · checked Oct 6, 2026
Local land-use decision clocks and appeals
High impact
Sets fixed timelines for hearings and decisions by town zoning, planning, appeals, wetlands and aquifer boards, with automatic approval of site plans and subdivisions left undecided, and a 15-day window to appeal in court.
C.G.S. 8-7d, 8-8 · Town land-use commissions; Superior Court · checked Oct 4, 2026
Wetlands and water
Aquifer protection areas
Medium impact
Protects land around major public water supply wellfields by banning new high-risk uses of hazardous materials and petroleum and requiring existing ones to register.
C.G.S. 22a-354i, 22a-354p, 22a-354s (ch. 446i) · Town aquifer protection agency; CT DEEP · checked Oct 4, 2026
Army Corps nationwide permits (2026 set)
Medium impactFederal
Fifty-seven general permits cover common activities with limited impacts, such as residential and commercial development, utility lines and land-based renewable energy, without an individual permit. Each district adds regional conditions. The 2026 set took effect March 15, 2026 and expires March 15, 2031.
91 FR 768 (January 8, 2026); 33 CFR Part 330 · US Army Corps of Engineers · checked Oct 6, 2026
Commercial stormwater permit for large paved sites
Medium impact
Controls polluted runoff from large paved commercial sites. Covered sites must register and run a stormwater management plan with sweeping, catch-basin cleaning, inspections and monitoring.
C.G.S. 22a-430b; Commercial Stormwater GP (2025) · CT DEEP · checked Oct 4, 2026
Construction stormwater general permit
Low impact
Controls erosion and polluted runoff from construction sites of 1 acre or more. Most must apply to DEEP and follow a stormwater pollution control plan until the site is stabilised.
C.G.S. 22a-430b; Construction Stormwater GP (2026) · CT DEEP · checked Oct 4, 2026
Federal permits to fill wetlands and waters (Section 404)
High impactFederal
Placing fill or dredged material in federally regulated waters or wetlands needs an Army Corps permit: a nationwide or regional general permit for smaller impacts, or an individual permit with public notice, alternatives analysis and mitigation for larger ones.
33 U.S.C. 1344; 33 CFR Parts 320–332; 40 CFR Part 230 · US Army Corps of Engineers (New York, Philadelphia, New England, Baltimore and Pittsburgh Districts) · checked Oct 6, 2026
Industrial stormwater general permit
Low impact
Controls polluted stormwater from industrial sites in listed sectors. Covered facilities must register, keep a certified pollution prevention plan, monitor runoff and fix problems, unless they certify no exposure.
C.G.S. 22a-430b; Industrial Stormwater GP (2025) · CT DEEP · checked Oct 4, 2026
Inland wetlands and watercourses permit
High impact
Protects inland wetlands and streams. Work in or near them needs a permit from the town wetlands agency, which must consider feasible and prudent alternatives.
C.G.S. 22a-36 to 22a-45d; R.C.S.A. 22a-39 · Town inland wetlands agency; CT DEEP · checked Oct 6, 2026
Pretreatment permits for discharges to sewer
Low impact
DEEP permits for industrial wastewater sent to a town sewer and treatment plant (POTW). Two 2025 general permits cover significant users and dewatering, and non-significant users; others need an individual permit.
C.G.S. 22a-430, 22a-430b, 22a-438; 2025 pretreatment GPs · CT DEEP · checked Oct 4, 2026
Septic and small sewage system permits
Medium impactChanges pending
Splits permitting of on-site septic systems between local health directors and DEEP by design flow, with the line at 10,000 gallons a day. Revised DPH rules and technical standards took effect 1 September 2026.
C.G.S. 22a-430(g), 22a-438, 19a-36; PA 23-207 · CT DPH and local health districts; CT DEEP · checked Oct 6, 2026
State water quality certification of federal permits (Section 401)
Medium impactFederalChanges pending
A federal permit that may cause a discharge to waters needs the state’s water quality certification, which can add conditions or be denied. The 2023 federal rule governs; EPA proposed on January 15, 2026 to narrow state review to point-source discharges, and the final rule has cleared White House review but is not yet published.
33 U.S.C. 1341; 40 CFR Part 121 · US EPA; NJDEP, NYSDEC, CT DEEP and PA DEP certify · checked Oct 7, 2026
Water diversion permit
Medium impactChanges pending
Regulates large water withdrawals and changes to watercourses. Projects above the thresholds need a DEEP diversion permit, with notice to the host town and a possible hearing.
C.G.S. 22a-365 to 22a-379; R.C.S.A. 22a-372-1 · CT DEEP · checked Oct 6, 2026
Which waters and wetlands are federally regulated (WOTUS)
High impactFederalChanges pending
Federal permits under the Clean Water Act apply only to “waters of the United States.” In NJ, NY, CT and PA the agencies apply the January 2023 definition as amended after the Supreme Court’s Sackett decision. A narrower definition is proposed; comments on the latest supplement close October 9, 2026.
33 U.S.C. 1362(7); 33 CFR 328.3; 40 CFR 120.2 · US EPA and US Army Corps of Engineers · checked Oct 9, 2026