Connecticut Water Quality Rankings
158 cities ranked · Data from EPA SDWIS
Connecticut water quality overview
Connecticut's drinking water quality is below average overall, with a state average score of 58.8 out of 100 — 15.4 points below the national average of 74.2. The median city score is 56.6, reflecting how water quality is distributed across the state's 158 ranked cities. 47% of cities scored a D or F, pointing to significant water quality challenges across much of the state. 44 cities did earn an A or B grade, showing that strong systems do exist. PFAS "forever chemicals" were detected in 102 of 158 cities (65%). Of those, 94 cities exceed the 2024 EPA maximum contaminant levels — a health concern requiring action. 3 cities have lead levels exceeding the EPA action level of 15 ppb, typically a sign of aging lead service lines or lead solder in older plumbing. Residents in these areas should use an NSF 53-certified filter. 134 cities have recorded health-based violations with the EPA — meaning contaminant levels exceeded safe limits or required testing was missed. Use the table below to find your city's specific record.
How Connecticut cities scored
Score distribution by range
State vs national average
Water quality across Connecticut
Each dot is a city, colored by grade. Size reflects population served. Click any city to view its full report.
Top & bottom cities in Connecticut
Best 10 cities
All 158 cities in Connecticut
| # | City | Grade | Score | Score | Population | Violations | Issues |
|---|---|---|---|---|---|---|---|
| 1 | Plymouth | A+ | 95.6 | 4K | 43 | Unresolved | |
| 2 | Uncasville | A | 92.2 | 32K | 3 | Health Unresolved | |
| 3 | Beacon Falls | A | 92.1 | 23K | 10 | Health Unresolved | |
| 4 | Sheffield | A | 91.2 | 987 | 5 | Health Unresolved | |
| 5 | Barkhamsted | A- | 89.7 | 8K | 61 | Health Unresolved | |
| 6 | Sheffield | A- | 89.3 | 1K | 13 | Health Unresolved | |
| 7 | Berlin | A- | 87 | 391K | 3 | Unresolved | |
| 8 | Berlin | A- | 87 | 391K | 3 | Unresolved | |
| 9 | Berlin | A- | 87 | 391K | 3 | Unresolved | |
| 10 | Berlin | A- | 87 | 391K | 3 | Unresolved | |
| 11 | Norfolk | A- | 86.3 | 913 | 10 | Health Unresolved | |
| 12 | Harwinton | B+ | 84.7 | 41K | 51 | Health Unresolved | |
| 13 | Ansonia | B+ | 84.4 | 419K | 32 | PFAS Unresolved | |
| 14 | Ansonia | B+ | 84.4 | 419K | 32 | PFAS Unresolved | |
| 15 | Ansonia | B+ | 84.4 | 419K | 32 | PFAS Unresolved | |
| 16 | Ansonia | B+ | 84.4 | 419K | 32 | PFAS Unresolved | |
| 17 | Ansonia | B+ | 84.4 | 419K | 32 | PFAS Unresolved | |
| 18 | Ansonia | B+ | 84.4 | 419K | 32 | PFAS Unresolved | |
| 19 | Salisbury | B+ | 84.2 | 3K | 43 | Health Unresolved | |
| 20 | North Canaan | B+ | 83.9 | 1K | 7 | Unresolved | |
| 21 | Berlin | B+ | 83.6 | 464K | 21 | Unresolved | |
| 22 | Lewisboro (T) | B+ | 83.6 | 656 | 104 | Health Unresolved | |
| 23 | Sprague | B+ | 83.4 | 1K | 60 | Unresolved | |
| 24 | Ansonia | B+ | 82.4 | 432K | 41 | PFAS Unresolved | |
| 25 | Ansonia | B+ | 82.4 | 432K | 41 | PFAS Unresolved | |
| 26 | Windham | B+ | 80.8 | 22K | 50 | Health Unresolved | |
| 27 | Berlin | B+ | 80.2 | 442K | 18 | Health PFAS Unresolved | |
| 28 | Ansonia | B+ | 80.2 | 420K | 45 | PFAS Unresolved | |
| 29 | Ansonia | B+ | 80.2 | 420K | 45 | PFAS Unresolved | |
| 30 | Hampton | B | 78.9 | 34K | 11 | Health PFAS Unresolved | |
| 31 | Franklin | B | 78.8 | 36K | 29 | Health PFAS Unresolved | |
| 32 | Franklin | B | 78.8 | 36K | 29 | Health PFAS Unresolved | |
| 33 | Mashantucket | B | 78 | 26K | 47 | Health PFAS Unresolved | |
| 34 | Berlin | B | 77 | 391K | 11 | Health Unresolved | |
| 35 | East Granby | B | 75.4 | 101K | 203 | PFAS Unresolved | |
| 36 | Ansonia | B- | 74.8 | 21K | 35 | Health PFAS Unresolved | |
| 37 | Berlin | B- | 74.6 | 446K | 97 | Health PFAS Unresolved | |
| 38 | Groton | B- | 74.5 | 12K | 88 | Health Unresolved | |
| 39 | Clinton | B- | 74.3 | 34K | 288 | PFAS Unresolved | |
| 40 | Chester | B- | 73.9 | 5K | 115 | Health Unresolved | |
| 41 | Berlin | B- | 73.8 | 492K | 206 | PFAS Unresolved | |
| 42 | Berlin | B- | 73.2 | 81K | 55 | Unresolved | |
| 43 | Franklin | B- | 70.5 | 37K | 72 | Health PFAS Unresolved | |
| 44 | Hampton | B- | 70.3 | 35K | 43 | Health PFAS Unresolved | |
| 45 | Plainville | C+ | 69.6 | 33K | 214 | Health PFAS Unresolved | |
| 46 | East Granby | C+ | 69.4 | 102K | 258 | Health PFAS Unresolved | |
| 47 | Ansonia | C+ | 68.8 | 477K | 85 | Health PFAS Unresolved | |
| 48 | Clinton | C+ | 68.5 | 35K | 337 | Health PFAS Unresolved | |
| 49 | New London | C+ | 68.2 | 44K | 158 | Unresolved | |
| 50 | Ansonia | C+ | 68.1 | 549K | 126 | Health PFAS Unresolved | |
| 51 | Bristol | C+ | 67.9 | 85K | 158 | Health PFAS Unresolved | |
| 52 | East Windsor | C+ | 67 | 21K | 212 | Health PFAS Unresolved | |
| 53 | Clinton | C+ | 66.2 | 34K | 347 | Health PFAS Unresolved | |
| 54 | East Granby | C+ | 66 | 17K | 106 | Health PFAS Unresolved | |
| 55 | Middlebury | C | 64.8 | 143K | 124 | Health Unresolved | |
| 56 | Barkhamsted | C | 64.7 | 8K | 218 | Health Unresolved | |
| 57 | Carroll | C | 64.5 | 1K | 62 | Health Lead Unresolved | |
| 58 | Chester | C | 64.1 | 5K | 276 | Health Unresolved | |
| 59 | Carroll | C | 64 | 2K | 64 | Health Lead Unresolved | |
| 60 | Berlin | C | 63.4 | 159K | 176 | Health PFAS Unresolved | |
| 61 | North Stonington | C | 63.2 | 2K | 267 | Health Unresolved | |
| 62 | Bristol | C | 63.1 | 62K | 363 | Health PFAS Unresolved | |
| 63 | Berlin | C | 62.5 | 396K | 262 | Health Unresolved | |
| 64 | Goshen | C | 62.3 | 4K | 72 | Health Unresolved | |
| 65 | Bristol | C | 62.1 | 59K | 245 | Health PFAS Unresolved | |
| 66 | Berlin | C | 60.9 | 544K | 228 | Health PFAS Unresolved | |
| 67 | Berlin | C | 60.5 | 544K | 236 | Health PFAS Unresolved | |
| 68 | East Lyme | C | 60.2 | 15K | 219 | Health PFAS Unresolved | |
| 69 | Avon | C | 60.1 | 6K | 122 | Health PFAS Unresolved | |
| 70 | Ansonia | C- | 60 | 456K | 127 | PFAS Unresolved | |
| 71 | East Granby | C- | 59.6 | 102K | 265 | Health PFAS Unresolved | |
| 72 | Beacon Falls | C- | 59 | 352K | 155 | Health PFAS Unresolved | |
| 73 | Beacon Falls | C- | 59 | 352K | 155 | Health PFAS Unresolved | |
| 74 | Beacon Falls | C- | 59 | 352K | 155 | Health PFAS Unresolved | |
| 75 | Beacon Falls | C- | 59 | 352K | 155 | Health PFAS Unresolved | |
| 76 | Beacon Falls | C- | 59 | 352K | 155 | Health PFAS Unresolved | |
| 77 | Beacon Falls | C- | 57.9 | 392K | 158 | Health PFAS Unresolved | |
| 78 | Beacon Falls | C- | 57.8 | 388K | 172 | Health PFAS Unresolved | |
| 79 | East Granby | C- | 57.8 | 153K | 315 | Health PFAS Unresolved | |
| 80 | Killingly | C- | 56.6 | 8K | 172 | Health PFAS Unresolved | |
| 81 | Killingworth | C- | 55.8 | 837 | 162 | Health Unresolved | |
| 82 | Middlebury | C- | 55.4 | 125K | 154 | Health PFAS Unresolved | |
| 83 | New London | C- | 55 | 46K | 307 | Health Unresolved | |
| 84 | Ansonia | D+ | 54.8 | 432K | 92 | Health PFAS Unresolved | |
| 85 | Berlin | D+ | 54.4 | 509K | 243 | Health PFAS Unresolved | |
| 86 | Clinton | D+ | 52.5 | 34K | 567 | Health PFAS Unresolved | |
| 87 | Groton | D+ | 52.2 | 50K | 123 | Health Unresolved | |
| 88 | Franklin | D+ | 52 | 37K | 132 | Health PFAS Unresolved | |
| 89 | Middlebury | D+ | 50 | 125K | 173 | Health Unresolved | |
| 90 | Brookfield | D+ | 50 | 5K | 791 | Health Unresolved | |
| 91 | Woodbury | D+ | 50 | 3K | 600 | Health Unresolved | |
| 92 | Ansonia | D | 49.4 | 784K | 200 | Health PFAS Unresolved | |
| 93 | Durham | D | 49 | 3K | 664 | Health Unresolved | |
| 94 | East Granby | D | 48.8 | 122K | 428 | Health PFAS Unresolved | |
| 95 | Beacon Falls | D | 48.2 | 434K | 234 | Health PFAS Unresolved | |
| 96 | Ansonia | D | 48 | 515K | 180 | Health PFAS Unresolved | |
| 97 | Harwinton | D | 48 | 38K | 784 | Health Unresolved | |
| 98 | Lower Sipaulovi, Lower Mishongnovi | D | 48 | 609 | 293 | Health Unresolved | |
| 99 | Lower Sipaulovi, Lower Mishongnovi | D | 48 | 609 | 293 | Health Unresolved | |
| 100 | Berlin | D | 47.9 | 477K | 259 | Health Unresolved | |
| 101 | Chester | D | 47.7 | 5K | 231 | Health Unresolved | |
| 102 | Beacon Falls | D | 47.5 | 453K | 237 | Health PFAS Unresolved | |
| 103 | Putnam | D | 47.4 | 8K | 179 | Health PFAS Unresolved | |
| 104 | Bow | D | 47.4 | 808 | 112 | Health Lead Unresolved | |
| 105 | Ashford | D | 47 | 1K | 588 | Health Unresolved | |
| 106 | Pomfret | D | 47 | 850 | 443 | Health Unresolved | |
| 107 | East Haddam | D | 47 | 673 | 306 | Health Unresolved | |
| 108 | Cromwell | D | 46.8 | 54K | 302 | Health Unresolved | |
| 109 | Clinton | D | 46.8 | 35K | 482 | Health PFAS Unresolved | |
| 110 | Kent | D | 46.7 | 2K | 242 | Health Unresolved | |
| 111 | Old Lyme | D | 46 | 5K | 778 | Health Unresolved | |
| 112 | Plainfield | D | 46 | 5K | 448 | Health Unresolved | |
| 113 | East Hampton | D | 46 | 3K | 889 | Health Unresolved | |
| 114 | Marlborough | D | 46 | 2K | 312 | Health Unresolved | |
| 115 | Beacon Falls | D | 45.4 | 463K | 245 | Health PFAS Unresolved | |
| 116 | Colchester | D | 45 | 6K | 663 | Health PFAS Unresolved | |
| 117 | Cromwell | F | 44.8 | 41K | 257 | Health Unresolved | |
| 118 | Berlin | F | 44.4 | 391K | 262 | Health Unresolved | |
| 119 | Middlebury | F | 44 | 9K | 436 | Health PFAS Unresolved | |
| 120 | Bethel | F | 43 | 72K | 313 | Health PFAS Unresolved | |
| 121 | Hebron | F | 43 | 3K | 376 | Health Unresolved | |
| 122 | Willington | F | 43 | 2K | 370 | Health Unresolved | |
| 123 | Beacon Falls | F | 42.6 | 352K | 229 | Health PFAS Unresolved | |
| 124 | Beacon Falls | F | 42.5 | 532K | 269 | Health PFAS Unresolved | |
| 125 | Griswold | F | 42.4 | 8K | 361 | Health Unresolved | |
| 126 | Bethel | F | 42 | 79K | 1590 | Health PFAS Unresolved | |
| 127 | Sharon | F | 42 | 865 | 154 | Health Unresolved | |
| 128 | Franklin | F | 41.9 | 38K | 457 | Health PFAS Unresolved | |
| 129 | Beacon Falls | F | 41.6 | 352K | 1850 | Health PFAS Unresolved | |
| 130 | Beacon Falls | F | 41.6 | 352K | 429 | Health PFAS Unresolved | |
| 131 | Beacon Falls | F | 41.5 | 553K | 232 | Health PFAS Unresolved | |
| 132 | Groton | F | 41.5 | 48K | 305 | Health Unresolved | |
| 133 | Berlin | F | 41 | 553K | 419 | Health PFAS Unresolved | |
| 134 | Washington | F | 41 | 1K | 335 | Health Unresolved | |
| 135 | Hopkinton | F | 41 | 769 | 266 | Health Unresolved | |
| 136 | Harwinton | F | 40.4 | 41K | 340 | Health Unresolved | |
| 137 | Putnam | F | 40 | 9K | 735 | Health PFAS Unresolved | |
| 138 | Berlin | F | 39.9 | 508K | 524 | Health PFAS Unresolved | |
| 139 | Beacon Falls | F | 39.8 | 423K | 500 | Health PFAS Unresolved | |
| 140 | East Granby | F | 39.6 | 120K | 573 | Health PFAS Unresolved | |
| 141 | Harwinton | F | 39.4 | 46K | 212 | Health PFAS Unresolved | |
| 142 | Coventry | F | 39 | 3K | 235 | Health Unresolved | |
| 143 | Ansonia | F | 38.7 | 419K | 234 | Health PFAS Unresolved | |
| 144 | Brookfield | F | 38.5 | 17K | 998 | Health PFAS Unresolved | |
| 145 | East Granby | F | 38.4 | 28K | 436 | Health PFAS Unresolved | |
| 146 | Killingly | F | 37.5 | 8K | 407 | Health PFAS Unresolved | |
| 147 | Beacon Falls | F | 36.6 | 525K | 257 | Health PFAS Unresolved | |
| 148 | East Granby | F | 36.4 | 103K | 324 | Health PFAS Unresolved | |
| 149 | Franklin | F | 35.9 | 62K | 1243 | Health PFAS Unresolved | |
| 150 | Beacon Falls | F | 35.6 | 361K | 484 | Health PFAS Unresolved | |
| 151 | Beacon Falls | F | 35.6 | 352K | 285 | Health PFAS Unresolved | |
| 152 | Bethel | F | 35 | 74K | 860 | Health PFAS Unresolved | |
| 153 | Putnam | F | 35 | 8K | 748 | Health PFAS Unresolved | |
| 154 | Ansonia | F | 34.5 | 573K | 663 | Health PFAS Unresolved | |
| 155 | Ansonia | F | 34.5 | 520K | 577 | Health PFAS Unresolved | |
| 156 | Franklin | F | 33.8 | 43K | 278 | Health PFAS Unresolved | |
| 157 | Ansonia | F | 33.5 | 591K | 555 | Health PFAS Unresolved | |
| 158 | East Granby | F | 33.4 | 153K | 811 | Health PFAS Unresolved |