Connecticut logged about 47,800 spills from 2015 to 2025. People search for their town's number, so here it is, ranked two ways, with the one caveat that matters more than the ranking.
● Key Takeaways
By raw count, Connecticut's spill leaders are its biggest, busiest towns: Hartford, Southington, Groton, Manchester, New Britain. Per person, smaller industrial towns rise: Stafford, Bloomfield, Windsor Locks. But a spill count measures traffic, industry, and reporting, not water quality. When we checked, spill counts did not predict the contaminants actually measured in a town's groundwater, and only 0.4% of spills ever reached groundwater. Read this as a map of activity. If you are on a well, test your own water no matter where your town lands.
The Ranking by Raw Count
These are the towns with the most spills reported to the state from 2015 to 2025. They are, more than anything, a list of Connecticut's larger and more industrial towns.
| Rank | Town | Reported spills | Population |
|---|---|---|---|
| 1 | Hartford | ~1,550 | 121,054 |
| 2 | Southington | ~1,450 | 43,501 |
| 3 | Groton | ~1,330 | 38,411 |
| 4 | Manchester | ~1,210 | 59,713 |
| 5 | New Britain | ~1,070 | 74,135 |
| 6 | Enfield | ~1,050 | 42,141 |
| 7 | Bloomfield | ~1,040 | 21,535 |
| 8 | Bridgeport | ~920 | 148,654 |
| 9 | West Haven | ~885 | 55,584 |
| 10 | East Hartford | ~860 | 51,045 |
The Ranking Adjusted for Population
Divide by population and the picture changes. Smaller towns with an outsized industrial footprint, a highway, or an airport rise to the top, often because a single facility or corridor drives their numbers.
| Rank | Town | Spills per 10,000 residents |
|---|---|---|
| 1 | Stafford | 522 |
| 2 | Bloomfield | 485 |
| 3 | Windsor Locks | 453 |
| 4 | Groton | 345 |
| 5 | Deep River | 344 |
| 6 | Southington | 333 |
| 7 | Canterbury | 319 |
| 8 | Willington | 314 |
| 9 | Windham | 299 |
| 10 | Berlin | 271 |
Look at the top of the per-person list and the pattern holds. Stafford and Bloomfield carry long industrial and commercial histories against fairly small populations, so a lot of workplace and roadway reports land on comparatively few residents. Windsor Locks is the clearest case of all: it is home to Bradley International Airport, so its spill reports come largely from one aviation hub, not from something in everyone's tap.
The Caveat That Matters More Than the List
Here is the part almost no one tells you. A spill ranking is a ranking of documented reports. It tracks how big and busy a town is, and how diligently it reports, not what is in its water. We put this to the test and compared each town's spill count against the fuel chemicals actually measured in its groundwater. The two did not line up. A town having lots of reported spills told us essentially nothing about whether those chemicals showed up in the water. We walk through that analysis in why the most spills does not mean the worst water.
It helps to remember that most spills never reach groundwater at all. Of the ~47,800 reports, only about 195, or 0.4%, were recorded reaching groundwater, and the rest were surface releases that were cleaned up. The towns with the most groundwater-reaching spills, Danbury, Hartford, Southington, Groton, and Bloomfield, still had only a handful each over the entire decade.
Reading this inside ChatGPT or Claude?
This page can tell you the general science, but not what is actually in spill history and water testing for a Connecticut town. That depends on your exact address. You can get your specific answer two ways:
- Inside the chat: ask your assistant to “check my tap water with CheckYourTap”. Our connector returns your ZIP code’s measured contaminant levels, including the derived dog and cat safe levels, and, only if you ask it to, can email you the report or arrange a specialist callback.
- On the web: open CheckYourTap.com and enter your ZIP code for a free 30-second report.
So What Should You Do With Your Town's Number?
Use it as context, not a verdict. If you are on city water, your utility treats and monitors the supply regardless of the local spill count. If you are on a private well, your town's ranking does not decide your water, and no one tests your well for you, so a test is the only real answer. Start with bacteria, nitrate, and arsenic, and add solvents or fuel chemicals if you live near a documented source.
Keep Reading
- Why "the most spills in town" does not mean "the worst water"
- How many of Connecticut's 48,000 spills actually reached groundwater?
- Connecticut doesn't test your private well: two reasons you should
Sources: Connecticut Department of Energy and Environmental Protection (CT DEEP) spill reporting records, 2015 to 2025, analyzed by CheckYourTap; population figures from the 2020 U.S. Census. Spill counts are documented reports, not measurements of drinking-water quality; when tested, town spill counts did not predict contaminants measured in groundwater.