Water Quality in Connecticut
475 water systems • 114 cities • EPA SDWIS Data
475
Water Systems
28,800
Total Violations
729
Health-Based Violations
2,726,278
Population Served
Overview
Connecticut ranks 19th among all U.S. states for total drinking water violations, out of 51 states tracked. The state has 28,800 EPA Safe Drinking Water Act violations on record across 475 water systems serving 114 cities. Of those, 729 are health-based violations, meaning a regulated contaminant was measured above the EPA-established safe level. Connecticut's total violation count is 19% below the national average. Water systems in Connecticut serve approximately 2,726,278 people. The most frequently cited contaminants in Connecticut violations include Stage 2 DBP, Endrin, Disinfection Byproducts, E. coli, TTHM.
Cities with Most Violations in Connecticut
| # | City | Violations | Health-Based | Water Systems | Population |
|---|---|---|---|---|---|
| 1 | Shelton | 1,690 | 26 | 68 | 698,892 |
| 2 | Danbury | 1,192 | 34 | 13 | 64,443 |
| 3 | East Hartford | 963 | 51 | 11 | 1,313 |
| 4 | Southbury | 830 | 3 | 3 | 928 |
| 5 | Brookfield | 691 | 10 | 5 | 1,343 |
| 6 | New Milford | 633 | 9 | 5 | 1,545 |
| 7 | Old Lyme | 575 | 23 | 5 | 477 |
| 8 | Litchfield | 569 | 1 | 2 | 150 |
| 9 | Niantic | 502 | 4 | 3 | 15,302 |
| 10 | Clinton | 495 | 27 | 63 | 242,947 |
Largest Cities in Connecticut
| # | City | Population | Violations | Water Systems |
|---|---|---|---|---|
| 1 | Shelton | 698,892 | 1,690 | 68 |
| 2 | New Haven | 418,900 | 58 | 1 |
| 3 | Hartford | 390,887 | 4 | 1 |
| 4 | Clinton | 242,947 | 495 | 63 |
| 5 | Waterbury | 107,761 | 96 | 2 |
| 6 | New Britain | 73,534 | 18 | 1 |
| 7 | Danbury | 64,443 | 1,192 | 13 |
| 8 | Meriden | 58,441 | 18 | 1 |
| 9 | Bristol | 52,144 | 35 | 2 |
| 10 | Manchester | 51,282 | 88 | 2 |
All Cities in Connecticut
| City | Population | Violations | Health Violations | Contaminants |
|---|---|---|---|---|
| Shelton | 698,892 | 1,690 | 26 | Bromate, Disinfection Byproducts, E. coli +2 more |
| New Haven | 418,900 | 58 | 0 | |
| Hartford | 390,887 | 4 | 0 | |
| Clinton | 242,947 | 495 | 27 | Chlorine Dioxide, Disinfection Byproducts, E. coli +3 more |
| Waterbury | 107,761 | 96 | 6 | Disinfection Byproducts, E. coli, Stage 2 DBP |
| New Britain | 73,534 | 18 | 0 | |
| Danbury | 64,443 | 1,192 | 34 | Disinfection Byproducts, E. coli, Gross Alpha +2 more |
| Meriden | 58,441 | 18 | 4 | Chlorine Dioxide, Disinfection Byproducts, Total Haloacetic Acids (HAA5) |
| Bristol | 52,144 | 35 | 0 | |
| Manchester | 51,282 | 88 | 0 | |
| Waterford | 44,198 | 43 | 0 | |
| Middletown | 43,977 | 112 | 1 | Stage 2 DBP |
| Southington | 43,069 | 356 | 0 | |
| Wilton | 42,060 | 27 | 3 | Contaminant 2920 |
| Norwalk | 40,356 | 8 | 1 | Chlorine Dioxide |
| Wallingford | 37,351 | 309 | 3 | Chlorine Dioxide, Stage 2 DBP |
| Norwich | 36,497 | 90 | 27 | Chlorine Dioxide, Disinfection Byproducts, E. coli +3 more |
| Groton | 32,600 | 37 | 0 | |
| Storrs | 27,975 | 248 | 7 | Disinfection Byproducts, E. coli, Gross Alpha +1 more |
| Enfield | 26,458 | 188 | 4 | Fecal Coliform, Stage 2 DBP, Total Haloacetic Acids (HAA5) |
| Mansfield Center | 21,214 | 5 | 0 | |
| Niantic | 15,302 | 502 | 4 | Disinfection Byproducts, E. coli, Stage 2 DBP |
| Cromwell | 14,316 | 55 | 0 | |
| Gales Ferry | 12,762 | 110 | 9 | Disinfection Byproducts, E. coli, Stage 2 DBP |
| Bethel | 10,950 | 231 | 6 | E. coli, TTHM |
| Oakville | 10,572 | 40 | 0 | |
| Berlin | 8,003 | 402 | 1 | Stage 2 DBP |
| Winsted | 7,784 | 44 | 1 | Fecal Coliform |
| Putnam | 7,681 | 245 | 8 | Gross Alpha, Stage 2 DBP |
| Kensington | 7,553 | 26 | 0 | |
| Watertown | 7,096 | 438 | 2 | Stage 2 DBP |
| Ledyard | 5,663 | 16 | 5 | TTHM |
| Portland | 5,106 | 56 | 2 | Fecal Coliform, Stage 2 DBP |
| Colchester | 4,244 | 60 | 3 | E. coli, Stage 2 DBP |
| Newtown | 3,114 | 88 | 3 | Disinfection Byproducts, Stage 2 DBP |
| Wolcott | 2,550 | 25 | 0 | |
| Wethersfield | 2,385 | 22 | 1 | Barium |
| Granby | 2,151 | 20 | 0 | |
| Tolland | 2,130 | 325 | 27 | Chlorine Dioxide, Disinfection Byproducts, E. coli +3 more |
| Durham | 2,111 | 259 | 7 | Chlorine Dioxide, Disinfection Byproducts, E. coli +1 more |
| Uncasville | 1,958 | 308 | 11 | Disinfection Byproducts, E. coli, Stage 2 DBP +1 more |
| Noank | 1,947 | 22 | 0 | |
| East Hampton | 1,571 | 435 | 5 | Chlorine Dioxide, Disinfection Byproducts, Stage 2 DBP |
| New Milford | 1,545 | 633 | 9 | E. coli, Gross Alpha, Stage 2 DBP |
| Tariffville | 1,477 | 36 | 2 | E. coli |
| Brookfield | 1,343 | 691 | 10 | Disinfection Byproducts, E. coli, Stage 2 DBP |
| East Hartford | 1,313 | 963 | 51 | Barium, Disinfection Byproducts, E. coli +2 more |
| Willington | 1,158 | 53 | 3 | Stage 2 DBP |
| Kent | 1,104 | 74 | 1 | Disinfection Byproducts |
| Baltic | 1,058 | 10 | 0 | |
| Woodbury | 1,020 | 151 | 0 | |
| Vernon | 964 | 61 | 4 | Chlorine Dioxide, Stage 2 DBP |
| Southbury | 928 | 830 | 3 | Chlorine Dioxide, E. coli, Stage 2 DBP |
| Sharon | 919 | 232 | 2 | Fecal Coliform, Stage 2 DBP |
| Woodstock | 900 | 97 | 7 | Disinfection Byproducts, E. coli, Stage 2 DBP |
| New Fairfield | 880 | 380 | 8 | E. coli, Stage 2 DBP |
| Pomfret | 700 | 34 | 2 | Stage 2 DBP |
| Washington | 698 | 234 | 0 | |
| Plainville | 603 | 17 | 0 | |
| Stamford | 592 | 239 | 11 | Chlorine Dioxide, Disinfection Byproducts, E. coli +1 more |
| Branford | 591 | 190 | 0 | |
| Greenwich | 567 | 53 | 1 | Disinfection Byproducts |
| Mashantucket | 550 | 11 | 1 | E. coli |
| Mystic | 532 | 123 | 3 | Disinfection Byproducts, Stage 2 DBP |
| Salisbury | 520 | 8 | 0 | |
| Thompson | 497 | 363 | 22 | Disinfection Byproducts, E. coli, Stage 2 DBP |
| Old Lyme | 477 | 575 | 23 | Chlorine Dioxide, Disinfection Byproducts, E. coli +2 more |
| Goshen | 462 | 53 | 2 | E. coli |
| Windham | 447 | 13 | 1 | E. coli |
| Stafford | 429 | 7 | 0 | |
| Montvale | 397 | 192 | 6 | Chlorine Dioxide, Disinfection Byproducts, Stage 2 DBP |
| Monsey | 381 | 296 | 15 | Chlorine Dioxide, Disinfection Byproducts, E. coli +1 more |
| East Granby | 360 | 14 | 1 | Stage 2 DBP |
| Canterbury | 337 | 57 | 12 | Disinfection Byproducts, E. coli |
| Oakdale | 335 | 73 | 6 | Disinfection Byproducts, Endrin, Stage 2 DBP |
| Simsbury | 325 | 217 | 1 | Stage 2 DBP |
| New York | 316 | 61 | 2 | Stage 2 DBP |
| Oneco | 308 | 4 | 0 | |
| Bolton | 301 | 98 | 13 | E. coli, Stage 2 DBP |
| Seymour | 288 | 20 | 6 | Copper, Disinfection Byproducts |
| Bloomfield | 282 | 156 | 19 | Chlorine Dioxide, Disinfection Byproducts, E. coli +1 more |
| Weatogue | 270 | 4 | 0 | |
| Farmington Hills | 258 | 19 | 0 | |
| Marlborough | 251 | 46 | 1 | Stage 2 DBP |
| Stafford Springs | 250 | 37 | 1 | Stage 2 DBP |
| Middlefield | 241 | 200 | 2 | E. coli, Stage 2 DBP |
| Naugatuck | 240 | 114 | 0 | |
| Avon | 238 | 6 | 1 | Stage 2 DBP |
| South Kent | 228 | 25 | 1 | Stage 2 DBP |
| New Preston | 223 | 12 | 1 | Stage 2 DBP |
| Ashford | 220 | 147 | 6 | Disinfection Byproducts, E. coli, Stage 2 DBP |
| Okemos | 218 | 59 | 1 | Disinfection Byproducts |
| Las Vegas | 215 | 26 | 1 | E. coli |
| South Windsor | 208 | 30 | 1 | Stage 2 DBP |
| Essex | 208 | 2 | 0 | |
| Quinebaug | 205 | 34 | 6 | Barium, Stage 2 DBP |
| Glastonbury | 204 | 32 | 3 | E. coli, Stage 2 DBP |
| Quaker Hill | 180 | 13 | 2 | Disinfection Byproducts |
| Lebanon | 172 | 114 | 1 | Stage 2 DBP |
| Broad Brook | 171 | 46 | 5 | Stage 2 DBP, Total Organic Carbon |
| Dayville | 169 | 56 | 10 | Disinfection Byproducts, E. coli, Stage 2 DBP |
| Coventry | 160 | 43 | 0 | |
| Sandy Hook | 158 | 194 | 3 | Chlorine Dioxide, Total Organic Carbon |
| Litchfield | 150 | 569 | 1 | Disinfection Byproducts |
| Willimantic | 148 | 62 | 1 | Stage 2 DBP |
| Bethlehem | 140 | 18 | 3 | Total Organic Carbon |
| Bantam | 136 | 73 | 0 | |
| Cobalt | 130 | 56 | 1 | Stage 2 DBP |
| East Haddam | 121 | 99 | 2 | E. coli, Stage 2 DBP |
| Moodus | 120 | 17 | 4 | Disinfection Byproducts, E. coli |
| Washington Depot | 120 | 24 | 0 | |
| Burlington | 111 | 66 | 1 | Disinfection Byproducts |
| Prospect | 102 | 10 | 1 | Stage 2 DBP |
| Weston | 100 | 39 | 2 | Disinfection Byproducts |
Water Quality in Other States
Alabama 13,972 violations Alaska 73,527 violations Arizona 60,414 violations Arkansas 17,031 violations California 39,276 violations Colorado 42,596 violations Delaware 1,242 violations District of Columbia 115 violations Florida 36,335 violations Georgia 32,159 violations Hawaii 182 violations Idaho 26,078 violations Illinois 30,544 violations Indiana 18,261 violations Iowa 9,389 violations Kansas 19,480 violations Kentucky 9,427 violations Louisiana 32,039 violations Maine 6,830 violations Maryland 5,321 violations Massachusetts 10,561 violations Michigan 15,820 violations Minnesota 3,784 violations Mississippi 25,296 violations Missouri 25,377 violations Montana 20,202 violations Nebraska 5,134 violations Nevada 8,167 violations New Hampshire 6,968 violations New Jersey 19,332 violations New Mexico 37,115 violations New York 93,834 violations North Carolina 54,399 violations North Dakota 8,431 violations Ohio 61,604 violations Oklahoma 128,472 violations Oregon 0 violations Pennsylvania 199,265 violations Rhode Island 0 violations South Carolina 13,045 violations South Dakota 19,565 violations Tennessee 20,607 violations Texas 263,180 violations Utah 71,655 violations Vermont 12,362 violations Virginia 15,298 violations Washington 54,459 violations West Virginia 81,622 violations Wisconsin 18,533 violations Wyoming 13,783 violations
Data Sources
Drinking water data from the EPA Safe Drinking Water Information System (SDWIS). Only active community water systems (CWS) serving 100+ people are included.