Connecticut Environment & Hazard Risk

Events per year

21,002 homes in Connecticut have flood insurance, about 2.1% of residential buildings. In high-risk flood zones, 15,938 of 31,281 homes (51%) are insured.

• Hurricane Sandy$18.48M · 563 claims
• Hurricane Irene$10.32M · 389 claims
• Flooding$1.52M · 123 claims
• Not a named storm$1.47M · 227 claims
• Hurricane Gloria$788K · 199 claims
• March 2010 Nor'easter$714K · 99 claims

Since 2021, 165 systems reported 274 health-based violations. 142 systems had a violation of any kind still open at last report. These had the most:

Select a county above to see every system that serves it.

Facilities in Connecticut reported 2.0 million lbs of toxic releases in 2024, 482,969 lbs of it into the air.

In 2022 the U.S. Census Bureau replaced Connecticut's 8 historical counties, which have had no county government since 1960, with the state's 9 planning regions. Some federal datasets still publish figures by the old counties. Old county lines do not match the new regions, so these figures cannot be split between regions. We show them here as published.

• Fairfield County

  Now part of Western Connecticut Planning Region, Greater Bridgeport Planning Region and Naugatuck Valley Planning Region

  Flood insurance claims

  12,667 claims, $284M paid (1978 to 2026)

  Costliest flood

  Hurricane Sandy (2012): $156M

• Hartford County

  Now part of Capitol Planning Region, Naugatuck Valley Planning Region and Northwest Hills Planning Region

  Flood insurance claims

  1,922 claims, $15.22M paid (1978 to 2026)

  Costliest flood

  Hurricane Irene (2011): $3.81M

• Litchfield County

  Now part of Northwest Hills Planning Region, Naugatuck Valley Planning Region and Western Connecticut Planning Region

  Flood insurance claims

  479 claims, $7.15M paid (1978 to 2024)

  Costliest flood

  Hurricane Irene (2011): $1.76M

• Middlesex County

  Now part of Lower Connecticut River Valley Planning Region

  Flood insurance claims

  2,242 claims, $38.32M paid (1978 to 2026)

  Costliest flood

  Hurricane Sandy (2012): $18.48M

• New Haven County

  Now part of South Central Connecticut Planning Region and Naugatuck Valley Planning Region

  Flood insurance claims

  9,609 claims, $173M paid (1978 to 2026)

  Costliest flood

  Hurricane Sandy (2012): $66.14M

• New London County

  Now part of Southeastern Connecticut Planning Region, Lower Connecticut River Valley Planning Region and Northeastern Connecticut Planning Region

  Flood insurance claims

  2,155 claims, $31.2M paid (1978 to 2026)

  Costliest flood

  Hurricane Sandy (2012): $20.79M

• Tolland County

  Now part of Capitol Planning Region and Northeastern Connecticut Planning Region

  Flood insurance claims

  167 claims, $1.79M paid (1978 to 2024)

  Costliest flood

  Not a named storm (1982): $117K

• Windham County

  Now part of Northeastern Connecticut Planning Region and Southeastern Connecticut Planning Region

  Flood insurance claims

  74 claims, $1.84M paid (1978 to 2024)

  Costliest flood

  March 2010 Nor'easter (2010): $819K

Source: FEMA NFIP flood insurance claims. Figures are for the old county as a whole.

Frequently asked questions

What is the biggest natural hazard in Connecticut?

By expected annual loss, hurricane costs the most in Connecticut ($184M a year), according to FEMA's National Risk Index.

How many storms hit Connecticut each year?

NOAA recorded 6,639 storm events in Connecticut since 1996, about 214 a year. The most common type is thunderstorm wind.

How many hurricanes have hit Connecticut?

Connecticut has had 4 hurricane landfalls since 1851, including 2 major hurricanes of Category 3 or stronger.

How many homes in Connecticut have flood insurance?

21,002 residential flood insurance policies are in force in Connecticut. Since 1978 the National Flood Insurance Program has paid $38.32M on 2,242 claims here.

How many Superfund sites are in Connecticut?

Connecticut has 17 Superfund sites on or deleted from EPA's National Priorities List.