Data: EPA SDWIS, NWS, State plumbing boards, Rewiring America Last verified: 2026-06-03

Connecticut water systems post below-average compliance metrics across multiple counties.

Score Distribution

How Connecticut's 433 ZIP codes are distributed across safety grades.

Top 10 Safest ZIP Codes in Connecticut

Highest Home Safety Scores in the state.

10 Lowest-Scoring ZIP Codes in Connecticut

County Rankings

Water quality breakdown by county. 8 counties with data in Connecticut.

Most Common Contaminants in Connecticut

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Overview

We track water quality, weather alerts, plumbing regulations, and energy rebates for 433 ZIP codes across Connecticut, covering 344 community water systems that serve approximately 2,316,239 people.

254 of 433 ZIP codes (59%) have recorded EPA violations. 343 health-based violations have been documented.

Plumbing Regulations

Connecticut follows the International Plumbing Code (2018 edition).

• Plumbing code: IPC (2018)
• Homeowner DIY: Licensed plumber required
• Water heater permit: Required
• Annual backflow test: Required

Full Connecticut regulations →

Areas with Most Violations

Areas with No Violations

Home Safety Score

Average Home Safety Score for Connecticut: C (65/100)

Lead & Copper

• Average lead level (90th percentile): 0.0027 mg/L (EPA action level: 0.015 mg/L)
• 0 ZIP codes exceed the EPA lead action level

Radon Risk

• High risk (Zone 1): 216 ZIP codes (50%)
• Moderate risk (Zone 2): 114 ZIP codes
• Low risk (Zone 3): 103 ZIP codes

ZIP Code Reports for Connecticut

Largest Communities

Lowest Safety Scores

Highest Safety Scores

All 433 ZIP Codes in Connecticut

• 06230 (Abington) [D]
• 06231 (Amston) [C]
• 06232 (Andover) [B] — 13 violations ⚠
• 06401 (Ansonia) [D]
• 06278 (Ashford) [B] — 28 violations ⚠
• 06001 (Avon) [B] — 6 violations ⚠
• 06233 (Ballouville) [D]
• 06330 (Baltic) [C] — 5 violations
• 06750 (Bantam) [B] — 15 violations
• 06063 (Barkhamsted) [B] — 2 violations
• 06403 (Beacon Falls) [D]
• 06037 (Berlin) [B] — 12 violations ⚠
• 06524 (Bethany) [D] — 18 violations
• 06801 (Bethel) [C] — 33 violations ⚠
• 06751 (Bethlehem) [B]
• 06002 (Bloomfield) [C] — 30 violations ⚠
• 06043 (Bolton) [C] — 28 violations ⚠
• 06404 (Botsford) [D]
• 06334 (Bozrah) [C]
• 06405 (Branford) [C] — 1 violation
• 06601 (Bridgeport) [D]
• 06602 (Bridgeport) [D]
• 06604 (Bridgeport) [F]
• 06605 (Bridgeport) [F]
• 06606 (Bridgeport) [F]
• 06607 (Bridgeport) [D]
• 06608 (Bridgeport) [D]
• 06610 (Bridgeport) [D]
• 06673 (Bridgeport) [D]
• 06699 (Bridgeport) [D]
• 06752 (Bridgewater) [C] — 4 violations
• 06010 (Bristol) [C] — 7 violations
• 06011 (Bristol) [B] — 7 violations
• 06016 (Broad Brook) [A] — 9 violations ⚠
• 06804 (Brookfield) [C] — 7 violations
• 06234 (Brooklyn) [C] — 32 violations ⚠
• 06013 (Burlington) [A]
• 06018 (Canaan) [B] — 3 violations ⚠
• 06331 (Canterbury) [C] — 11 violations ⚠
• 06019 (Canton) [A] — 4 violations ⚠
• 06020 (Canton Center) [B]
• 06409 (Centerbrook) [D]
• 06332 (Central Village) [D]
• 06235 (Chaplin) [D] — 5 violations ⚠
• 06408 (Cheshire) [D] — 16 violations ⚠
• 06410 (Cheshire) [D] — 16 violations ⚠
• 06411 (Cheshire) [D] — 16 violations ⚠
• 06412 (Chester) [D] — 7 violations ⚠
• 06413 (Clinton) [D] — 5 violations ⚠
• 06414 (Cobalt) [D] — 11 violations ⚠
• 06415 (Colchester) [C] — 25 violations ⚠
• 06021 (Colebrook) [C]
• 06022 (Collinsville) [C]
• 06237 (Columbia) [B] — 2 violations
• 06753 (Cornwall) [B]
• 06754 (Cornwall Bridge) [C]
• 06807 (Cos Cob) [D]
• 06238 (Coventry) [B] — 7 violations ⚠
• 06416 (Cromwell) [C] — 1 violation
• 06810 (Danbury) [C] — 9 violations ⚠
• 06811 (Danbury) [C] — 9 violations ⚠
• 06813 (Danbury) [C] — 9 violations ⚠
• 06814 (Danbury) [C] — 9 violations ⚠
• 06816 (Danbury) [C] — 9 violations ⚠
• 06817 (Danbury) [C] — 9 violations ⚠
• 06239 (Danielson) [B] — 2 violations ⚠
• 06820 (Darien) [F]
• 06241 (Dayville) [D] — 15 violations ⚠
• 06417 (Deep River) [C] — 3 violations ⚠
• 06418 (Derby) [D]
• 06422 (Durham) [C] — 34 violations ⚠
• 06023 (East Berlin) [B]
• 06024 (East Canaan) [C]
• 06025 (East Glastonbury) [D]
• 06026 (East Granby) [B] — 25 violations ⚠
• 06423 (East Haddam) [C] — 11 violations ⚠
• 06424 (East Hampton) [C] — 25 violations ⚠
• 06108 (East Hartford) [C] — 30 violations ⚠
• 06118 (East Hartford) [C] — 30 violations ⚠
• 06128 (East Hartford) [C] — 30 violations ⚠
• 06138 (East Hartford) [C] — 30 violations ⚠
• 06027 (East Hartland) [D]
• 06512 (East Haven) [F]
• 06243 (East Killingly) [D]
• 06333 (East Lyme) [C] — 2 violations
• 06088 (East Windsor) [B] — 15 violations ⚠
• 06028 (East Windsor Hill) [C]
• 06244 (East Woodstock) [D]
• 06242 (Eastford) [C]
• 06612 (Easton) [D]
• 06029 (Ellington) [B]
• 06082 (Enfield) [B] — 24 violations ⚠
• 06083 (Enfield) [A] — 24 violations ⚠
• 06426 (Essex) [D] — 15 violations ⚠
• 06245 (Fabyan) [D]
• 06824 (Fairfield) [D] — 8 violations ⚠
• 06825 (Fairfield) [D] — 8 violations ⚠
• 06828 (Fairfield) [C] — 8 violations ⚠
• 06031 (Falls Village) [C]
• 06030 (Farmington) [A] — 3 violations ⚠
• 06032 (Farmington) [B] — 3 violations ⚠
• 06034 (Farmington) [A] — 3 violations ⚠
• 06335 (Gales Ferry) [C] — 12 violations ⚠
• 06755 (Gaylordsville) [C]
• 06829 (Georgetown) [C]
• 06336 (Gilman) [D]
• 06033 (Glastonbury) [B] — 9 violations ⚠
• 06756 (Goshen) [C] — 16 violations
• 06035 (Granby) [B] — 6 violations
• 06838 (Greens Farms) [D]
• 06830 (Greenwich) [C]
• 06831 (Greenwich) [C]
• 06836 (Greenwich) [C]
• 06246 (Grosvenor Dale) [C]
• 06340 (Groton) [D] — 18 violations
• 06349 (Groton) [D] — 18 violations
• 06437 (Guilford) [C] — 1 violation
• 06438 (Haddam) [C] — 1 violation
• 06439 (Hadlyme) [D]
• 06514 (Hamden) [D]
• 06517 (Hamden) [D]
• 06518 (Hamden) [F]
• 06247 (Hampton) [C]
• 06350 (Hanover) [D]
• 06101 (Hartford) [A] — 1 violation
• 06102 (Hartford) [A] — 1 violation
• 06103 (Hartford) [A] — 1 violation
• 06104 (Hartford) [A] — 1 violation
• 06105 (Hartford) [A] — 1 violation
• 06106 (Hartford) [A] — 1 violation
• 06112 (Hartford) [A] — 1 violation
• 06114 (Hartford) [A] — 1 violation
• 06115 (Hartford) [A] — 1 violation
• 06120 (Hartford) [A] — 1 violation
• 06123 (Hartford) [A] — 1 violation
• 06126 (Hartford) [A] — 1 violation
• 06132 (Hartford) [A] — 1 violation
• 06134 (Hartford) [A] — 1 violation
• 06140 (Hartford) [A] — 1 violation
• 06141 (Hartford) [A] — 1 violation
• 06142 (Hartford) [A] — 1 violation
• 06143 (Hartford) [A] — 1 violation
• 06144 (Hartford) [A] — 1 violation
• 06145 (Hartford) [A] — 1 violation
• 06146 (Hartford) [A] — 1 violation
• 06147 (Hartford) [A] — 1 violation
• 06150 (Hartford) [A] — 1 violation
• 06151 (Hartford) [A] — 1 violation
• 06152 (Hartford) [A] — 1 violation
• 06153 (Hartford) [A] — 1 violation
• 06154 (Hartford) [A] — 1 violation
• 06155 (Hartford) [A] — 1 violation
• 06156 (Hartford) [A] — 1 violation
• 06160 (Hartford) [A] — 1 violation
• 06161 (Hartford) [A] — 1 violation
• 06167 (Hartford) [A] — 1 violation
• 06176 (Hartford) [A] — 1 violation
• 06180 (Hartford) [A] — 1 violation
• 06183 (Hartford) [A] — 1 violation
• 06199 (Hartford) [A] — 1 violation
• 06791 (Harwinton) [B] — 1 violation
• 06440 (Hawleyville) [D]
• 06248 (Hebron) [B] — 12 violations ⚠
• 06441 (Higganum) [D]
• 06442 (Ivoryton) [D]
• 06351 (Jewett City) [C] — 13 violations ⚠
• 06757 (Kent) [B] — 13 violations ⚠
• 06419 (Killingworth) [C] — 8 violations ⚠
• 06758 (Lakeside) [D]
• 06039 (Lakeville) [B] — 1 violation
• 06249 (Lebanon) [C] — 8 violations ⚠
• 06339 (Ledyard) [D] — 8 violations ⚠
• 06759 (Litchfield) [C] — 26 violations
• 06443 (Madison) [C]
• 06040 (Manchester) [A] — 5 violations
• 06041 (Manchester) [A] — 5 violations
• 06042 (Manchester) [A] — 5 violations
• 06045 (Manchester) [A] — 5 violations
• 06250 (Mansfield Center) [B] — 1 violation
• 06251 (Mansfield Depot) [C]
• 06444 (Marion) [C]
• 06447 (Marlborough) [A] — 2 violations ⚠
• 06338 (Mashantucket) [C] — 7 violations ⚠
• 06450 (Meriden) [C] — 5 violations ⚠
• 06451 (Meriden) [C] — 5 violations ⚠
• 06454 (Meriden) [C] — 5 violations ⚠
• 06456 (Middle Haddam) [D]
• 06762 (Middlebury) [C] — 1 violation
• 06455 (Middlefield) [C] — 19 violations ⚠
• 06457 (Middletown) [C] — 14 violations ⚠
• 06459 (Middletown) [C] — 14 violations ⚠
• 06460 (Milford) [D]
• 06461 (Milford) [D]
• 06467 (Milldale) [B]
• 06468 (Monroe) [C]
• 06353 (Montville) [C] — 18 violations ⚠
• 06469 (Moodus) [C] — 6 violations ⚠
• 06354 (Moosup) [C]
• 06763 (Morris) [B] — 15 violations ⚠
• 06355 (Mystic) [D] — 6 violations
• 06770 (Naugatuck) [C]
• 06050 (New Britain) [A] — 1 violation
• 06051 (New Britain) [A] — 1 violation
• 06052 (New Britain) [A] — 1 violation
• 06053 (New Britain) [A] — 1 violation
• 06840 (New Canaan) [D]
• 06812 (New Fairfield) [C] — 4 violations
• 06057 (New Hartford) [B] — 7 violations ⚠
• 06501 (New Haven) [B]
• 06502 (New Haven) [C]
• 06503 (New Haven) [B]
• 06504 (New Haven) [C]
• 06505 (New Haven) [B]
• 06506 (New Haven) [B]
• 06507 (New Haven) [B]
• 06508 (New Haven) [C]
• 06509 (New Haven) [C]
• 06510 (New Haven) [B]
• 06511 (New Haven) [C]
• 06513 (New Haven) [C]
• 06515 (New Haven) [C]
• 06519 (New Haven) [C]
• 06520 (New Haven) [C]
• 06521 (New Haven) [C]
• 06530 (New Haven) [C]
• 06531 (New Haven) [B]
• 06532 (New Haven) [C]
• 06533 (New Haven) [C]
• 06534 (New Haven) [C]
• 06535 (New Haven) [C]
• 06536 (New Haven) [C]
• 06537 (New Haven) [C]
• 06538 (New Haven) [C]
• 06540 (New Haven) [B]
• 06320 (New London) [D]
• 06776 (New Milford) [C] — 48 violations ⚠
• 06777 (New Preston Marble Dale) [C]
• 06111 (Newington) [B] — 2 violations
• 06131 (Newington) [A] — 2 violations
• 06470 (Newtown) [C] — 62 violations ⚠
• 06357 (Niantic) [D] — 20 violations ⚠
• 06058 (Norfolk) [B] — 1 violation
• 06471 (North Branford) [C] — 21 violations ⚠
• 06059 (North Canton) [D]
• 06254 (North Franklin) [D]
• 06060 (North Granby) [B]
• 06255 (North Grosvenordale) [C]
• 06473 (North Haven) [D]
• 06359 (North Stonington) [C] — 4 violations
• 06474 (North Westchester) [D]
• 06256 (North Windham) [D]
• 06778 (Northfield) [D]
• 06472 (Northford) [D]
• 06850 (Norwalk) [C] — 2 violations ⚠
• 06851 (Norwalk) [C] — 2 violations ⚠
• 06852 (Norwalk) [C] — 2 violations ⚠
• 06853 (Norwalk) [D] — 2 violations ⚠
• 06854 (Norwalk) [D] — 2 violations ⚠
• 06855 (Norwalk) [D] — 2 violations ⚠
• 06856 (Norwalk) [C] — 2 violations ⚠
• 06857 (Norwalk) [C] — 2 violations ⚠
• 06858 (Norwalk) [C] — 2 violations ⚠
• 06859 (Norwalk) [C] — 2 violations ⚠
• 06860 (Norwalk) [C] — 2 violations ⚠
• 06360 (Norwich) [D] — 7 violations ⚠
• 06370 (Oakdale) [C] — 9 violations ⚠
• 06779 (Oakville) [B] — 9 violations
• 06870 (Old Greenwich) [F]
• 06371 (Old Lyme) [D] — 27 violations ⚠
• 06372 (Old Mystic) [D]
• 06475 (Old Saybrook) [F]
• 06373 (Oneco) [B]
• 06477 (Orange) [D] — 1 violation
• 06478 (Oxford) [C] — 1 violation
• 06379 (Pawcatuck) [D]
• 06781 (Pequabuck) [C]
• 06061 (Pine Meadow) [D]
• 06374 (Plainfield) [B] — 8 violations ⚠
• 06062 (Plainville) [B] — 4 violations
• 06479 (Plantsville) [C]
• 06782 (Plymouth) [B]
• 06258 (Pomfret) [D] — 25 violations ⚠
• 06259 (Pomfret Center) [B] — 12 violations ⚠
• 06064 (Poquonock) [B]
• 06480 (Portland) [C] — 6 violations ⚠
• 06365 (Preston) [C] — 10 violations ⚠
• 06712 (Prospect) [C] — 7 violations ⚠
• 06260 (Putnam) [B] — 12 violations ⚠
• 06375 (Quaker Hill) [C] — 2 violations
• 06262 (Quinebaug) [B] — 8 violations ⚠
• 06896 (Redding) [D]
• 06875 (Redding Center) [D]
• 06876 (Redding Ridge) [D]
• 06877 (Ridgefield) [C] — 4 violations
• 06879 (Ridgefield) [C] — 4 violations
• 06878 (Riverside) [D]
• 06065 (Riverton) [C]
• 06481 (Rockfall) [D] — 7 violations ⚠
• 06067 (Rocky Hill) [B] — 6 violations ⚠
• 06263 (Rogers) [D]
• 06783 (Roxbury) [B] — 7 violations
• 06420 (Salem) [C] — 19 violations ⚠
• 06068 (Salisbury) [B] — 2 violations
• 06482 (Sandy Hook) [D] — 35 violations
• 06264 (Scotland) [D]
• 06483 (Seymour) [C]
• 06069 (Sharon) [B] — 14 violations ⚠
• 06484 (Shelton) [C] — 19 violations ⚠
• 06784 (Sherman) [C]
• 06070 (Simsbury) [B] — 13 violations ⚠
• 06071 (Somers) [B] — 1 violation
• 06072 (Somersville) [D]
• 06487 (South Britain) [D]
• 06073 (South Glastonbury) [C]
• 06785 (South Kent) [B] — 7 violations ⚠
• 06376 (South Lyme) [D]
• 06265 (South Willington) [D]
• 06266 (South Windham) [D]
• 06074 (South Windsor) [B] — 14 violations ⚠
• 06267 (South Woodstock) [D]
• 06488 (Southbury) [D] — 10 violations
• 06489 (Southington) [B] — 8 violations
• 06890 (Southport) [D]
• 06075 (Stafford) [C] — 3 violations ⚠
• 06076 (Stafford Springs) [C] — 3 violations ⚠
• 06077 (Staffordville) [D]
• 06901 (Stamford) [C] — 40 violations ⚠
• 06902 (Stamford) [D] — 40 violations ⚠
• 06903 (Stamford) [C] — 40 violations ⚠
• 06904 (Stamford) [C] — 40 violations ⚠
• 06905 (Stamford) [C] — 40 violations ⚠
• 06906 (Stamford) [C] — 40 violations ⚠
• 06907 (Stamford) [C] — 40 violations ⚠
• 06910 (Stamford) [C] — 40 violations ⚠
• 06911 (Stamford) [C] — 40 violations ⚠
• 06912 (Stamford) [C] — 40 violations ⚠
• 06913 (Stamford) [C] — 40 violations ⚠
• 06914 (Stamford) [C] — 40 violations ⚠
• 06920 (Stamford) [C] — 40 violations ⚠
• 06921 (Stamford) [C] — 40 violations ⚠
• 06922 (Stamford) [C] — 40 violations ⚠
• 06925 (Stamford) [C] — 40 violations ⚠
• 06926 (Stamford) [C] — 40 violations ⚠
• 06927 (Stamford) [C] — 40 violations ⚠
• 06928 (Stamford) [C] — 40 violations ⚠
• 06377 (Sterling) [B]
• 06491 (Stevenson) [D]
• 06378 (Stonington) [C] — 1 violation
• 06268 (Storrs Mansfield) [C]
• 06269 (Storrs Mansfield) [D]
• 06614 (Stratford) [D]
• 06615 (Stratford) [F]
• 06078 (Suffield) [A]
• 06080 (Suffield) [A]
• 06079 (Taconic) [D]
• 06380 (Taftville) [C]
• 06081 (Tariffville) [A] — 7 violations ⚠
• 06786 (Terryville) [C]
• 06787 (Thomaston) [C]
• 06277 (Thompson) [B] — 10 violations ⚠
• 06084 (Tolland) [B] — 27 violations ⚠
• 06790 (Torrington) [B] — 12 violations ⚠
• 06792 (Torrington) [B] — 12 violations ⚠
• 06611 (Trumbull) [C] — 4 violations
• 06382 (Uncasville) [C] — 5 violations ⚠
• 06085 (Unionville) [C]
• 06087 (Unionville) [C]
• 06066 (Vernon Rockville) [C]
• 06383 (Versailles) [D]
• 06384 (Voluntown) [C] — 2 violations ⚠
• 06492 (Wallingford) [C] — 24 violations ⚠
• 06493 (Wallingford) [C] — 24 violations ⚠
• 06494 (Wallingford) [C] — 24 violations ⚠
• 06495 (Wallingford) [C] — 24 violations ⚠
• 06793 (Washington) [B] — 11 violations
• 06794 (Washington Depot) [B] — 4 violations
• 06701 (Waterbury) [C] — 22 violations ⚠
• 06702 (Waterbury) [C] — 22 violations ⚠
• 06703 (Waterbury) [C] — 22 violations ⚠
• 06704 (Waterbury) [C] — 22 violations ⚠
• 06705 (Waterbury) [C] — 22 violations ⚠
• 06706 (Waterbury) [C] — 22 violations ⚠
• 06708 (Waterbury) [C] — 22 violations ⚠
• 06710 (Waterbury) [C] — 22 violations ⚠
• 06720 (Waterbury) [C] — 22 violations ⚠
• 06721 (Waterbury) [C] — 22 violations ⚠
• 06722 (Waterbury) [C] — 22 violations ⚠
• 06723 (Waterbury) [C] — 22 violations ⚠
• 06724 (Waterbury) [C] — 22 violations ⚠
• 06725 (Waterbury) [C] — 22 violations ⚠
• 06726 (Waterbury) [C] — 22 violations ⚠
• 06749 (Waterbury) [C] — 22 violations ⚠
• 06385 (Waterford) [C] — 9 violations
• 06795 (Watertown) [B] — 23 violations ⚠
• 06387 (Wauregan) [D]
• 06089 (Weatogue) [A]
• 06796 (West Cornwall) [C]
• 06090 (West Granby) [D]
• 06107 (West Hartford) [C]
• 06110 (West Hartford) [C]
• 06117 (West Hartford) [C]
• 06119 (West Hartford) [C]
• 06127 (West Hartford) [C]
• 06133 (West Hartford) [C]
• 06137 (West Hartford) [C]
• 06091 (West Hartland) [D]
• 06516 (West Haven) [D] — 3 violations ⚠
• 06388 (West Mystic) [B]
• 06092 (West Simsbury) [C]
• 06093 (West Suffield) [C]
• 06498 (Westbrook) [D] — 3 violations ⚠
• 06883 (Weston) [C] — 1 violation
• 06880 (Westport) [D]
• 06881 (Westport) [D]
• 06888 (Westport) [D]
• 06889 (Westport) [D]
• 06109 (Wethersfield) [B] — 2 violations
• 06129 (Wethersfield) [A] — 2 violations
• 06226 (Willimantic) [B] — 3 violations ⚠
• 06279 (Willington) [C] — 15 violations ⚠
• 06897 (Wilton) [C] — 2 violations
• 06094 (Winchester Center) [D]
• 06280 (Windham) [B] — 2 violations ⚠
• 06006 (Windsor) [C]
• 06095 (Windsor) [C]
• 06096 (Windsor Locks) [C]
• 06098 (Winsted) [B]
• 06716 (Wolcott) [C] — 7 violations ⚠
• 06525 (Woodbridge) [D]
• 06798 (Woodbury) [B] — 16 violations ⚠
• 06281 (Woodstock) [D] — 16 violations ⚠
• 06282 (Woodstock Valley) [D]
• 06389 (Yantic) [C]

Data Sources

• Water quality: EPA Safe Drinking Water Information System (SDWIS)
• Regulations: State plumbing boards, ICC, IAPMO

Updated daily.

Frequently Asked Questions

Is the water safe to drink in Connecticut?

Connecticut has 344 community water systems serving 2,316,239 people across 433 ZIP codes. There are 3,061 recorded violations, including 343 health-based. 254 of 433 ZIP codes have at least one violation.

What plumbing code does Connecticut follow?

Connecticut follows the IPC plumbing code. A licensed plumber is generally required for plumbing work.

What is the radon risk in Connecticut?

50% of ZIP codes in Connecticut fall in EPA Radon Zone 1 (highest risk).