EWG's Tap Water Database — 2019 UPDATE


Haloacetic acids (HAA5)

Status: National drinking water standard exists


Haloacetic acids are formed when disinfectants such as chlorine are added to tap water. The group of five haloacetic acids regulated by federal standards includes monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid. Read More.

Haloacetic acids are harmful during pregnancy and may increase the risk of cancer. Haloacetic acids are genotoxic, which means that they induce mutations and DNA damage. Multiple studies by the National Toxicology Program have demonstrated the cancer-causing properties of individual haloacetic acids in laboratory animals. The Department of Health and Human Services is currently considering listing di- or tri-haloacetic acids for possible inclusion in its comprehensive Report on Carcinogens.

Click here to read more about disinfection byproducts.




states detected


utilities detected

278 million

people served

Health concerns for haloacetic acids (HAA5)


Harm to fetal growth and development

State and national drinking water standards and health guidelines

EPA Maximum Contaminant
Level (MCL) 60 ppb

The legal limit for the group of five haloacetic acids (HAA5), established in 1998, was based on the need for residual disinfectant levels in water served to customers and the cost of treatment. This limit does not fully protect against the risk of cancer and harm to the developing fetus due to exposure to haloacetic acids.

ppb = parts per billion

States reporting haloacetic acids (HAA5) in drinking water

State UtilitiesPeople Served
New York1,58619,662,816
North Carolina8357,581,912
New Jersey1814,860,659
South Carolina3533,782,203
New Mexico3071,755,764
West Virginia4161,533,689
Rhode Island421,002,396
New Hampshire147740,710
North Dakota283686,294
District Of Columbia4664,572
South Dakota236574,190

Filtering technologies that reduce haloacetic acids (HAA5)

carbon filter icon

Activated Carbon

reverse osmosis icon

Reverse Osmosis

Utilities with the highest amounts of haloacetic acids (HAA5), 2015-2017

UtilityLocationTestsAverage levelPeople served
Red Gate Mobile Home ParkShelton, WA1 of 1223.3 ppb23
Elmdale, City ofElmdale, KS1 of 1200.0 ppb53
Vallenar View Mobile Home ParkKetchikan, AK2 of 2195.8 ppb225
Thorne Bay, City ofThorne Bay, AK9 of 9174.4 ppb470
Hudson Gaars Mill Water SystemSikes, LA24 of 24172.2 ppb660
Vixen Water System WestChatham, LA36 of 36165.9 ppb288
Orient Water CompanyTonasket, WA10 of 10151.9 ppb100
Truelight Redevelopment GroupAnguilla, MS22 of 22147.7 ppb92
Bethlehem Village DistrictBethlehem, NH8 of 8143.6 ppb1,700
Fairview Union Water System*Campti, LA48 of 48143.5 ppb2,205
Severy, City ofSevery, KS10 of 10141.1 ppb241
Tatitlek Water SystemTatitlek, AK4 of 4139.8 ppb95
Vixen Water System EastChatham, LA32 of 32139.5 ppb486
Philmont Boy Scout Ranch - HeadquartersCimarron, NM24 of 24128.7 ppb2,150
Elk City, City ofElk City, KS13 of 13127.3 ppb314
Lakewood Water SystemLufkin, TX10 of 10122.6 ppb42
Winebrook Hills Water DistrictNewcomb, NY12 of 12116.4 ppb250
Ryan Utilities AuthorityRyan, OK22 of 22110.8 ppb800
Sandy Point 480 Water SystemCampti, LA28 of 34108.7 ppb675
Pappas & Company (coalinga)Mendota, CA12 of 12108.4 ppb25
City of Rhome*Rhome, TX24 of 24108.4 ppb1,770
Koyukuk Safewater FacilityKoyukuk, AK1 of 1108.0 ppb97
Best Road Mutual Water CompanyHollister, CA7 of 7104.5 ppb133
East Columbia Water SystemColumbia, LA16 of 16103.9 ppb2,640
Tupper Lake VTupper Lake, NY22 of 22102.8 ppb5,500
Fcsa #30/el PorvenirFresno, CA11 of 11100.9 ppb130
City of NomeNome, TX15 of 16100.7 ppb753
Stringtown Public Works AuthorityStringtown, OK23 of 24100.6 ppb1,105
LowvilleLowville, NY12 of 1298.8 ppb350
Franklin County Rural Water District 2Ottawa, KS3 of 396.3 ppb400
Rye, Town ofRye, CO13 of 1396.0 ppb244
Beechwood Water Supply CorporationHemphill, TX16 of 1694.8 ppb1,143
Osage County Rural Water District # 20 (hulah)Bartlesville, OK12 of 1293.2 ppb350
Terra Bella Irrigation District - TbtTerra Bella, CA24 of 2492.8 ppb2,340
City of HuxleyShelbyville, TX22 of 2292.7 ppb2,290
Lowndes County-spring Creek S/dValdosta, GA24 of 2492.2 ppb2,959
Central Yazoo #4-bentonYazoo City, MS1 of 191.0 ppb1,083
Oceanside WD - Cape MearesOceanside, OR1 of 190.6 ppb150
Barnsdall*Barnsdall, OK19 of 1989.3 ppb1,243
Forest Water Supply CorporationWells, TX24 of 2486.7 ppb561
Fcsa #32/cantua CreekFresno, CA11 of 1186.6 ppb250
Surfwood Mutual Water CorporationMendocino, CA10 of 1086.1 ppb160
Circle Court Mobile ParkEast Aurora, NY11 of 1184.6 ppb90
Atoka County Rural Water, Sewer & Solid Waste Management District #4*Atoka, OK20 of 2482.6 ppb3,000
Harvest Gold SubdivisionBloomfield, NM4 of 581.6 ppb522
Carthage, Town ofCarthage, NC24 of 2481.4 ppb2,767
Alpat Water Utility-creekwood DivisionAnchorage, AK6 of 680.8 ppb192
Springfield Hospital DistributionSykesville, MD11 of 1180.3 ppb1,500
Amherst, Town ofAmherst, VA40 of 4080.2 ppb4,998
Dearing, City of*Dearing, KS4 of 480.0 ppb408

* This water utility supplies finished drinking water to at least one other water utility. The purchasing utility is not required to test for or report Haloacetic acids (HAA5), but it likely has the contaminant in its water supply.

UtilityLocationTestsAverage levelPeople served
Walnut Creek SUD*Springtown, TX46 of 4677.1 ppb23,807
Larue County Water District #1Buffalo, KY26 of 2661.5 ppb10,166
Eubank Water System*Eubank, KY48 of 4861.4 ppb12,492
City of Beeville*Beeville, TX48 of 4857.9 ppb15,039
Southwest Ouachita Waterworks Inc.West Monroe, LA40 of 4055.9 ppb10,092
Magoffin County Water DistrictSalyersville, KY24 of 2455.0 ppb10,294
Martin County Water District #1Inez, KY34 of 3454.8 ppb10,843
Okmulgee*Okmulgee, OK48 of 4854.6 ppb13,495
Russell Springs Water & Sewer*Russell Springs, KY37 of 3754.0 ppb11,567
Danville City Water Works*Danville, KY49 of 4953.1 ppb32,600
GCWSD Waccamaw NeckPawleys Island, SC52 of 5252.5 ppb34,367
Watertown City*Watertown, NY144 of 14452.4 ppb29,406
Baldwin CountyMilledgeville, GA48 of 4852.3 ppb22,279
South Central Water AssnRaymond, MS50 of 5052.0 ppb11,756
Lamar County Water Supply District*Paris, TX48 of 4851.8 ppb22,269
City of Deerfield BeachDeerfield Beach, FL74 of 7451.7 ppb52,749
Muskogee*Muskogee, OK84 of 8451.6 ppb38,310
Oneida Water and Sewer Comm.Oneida, TN48 of 4851.6 ppb11,282
Claremore*Claremore, OK52 of 5251.6 ppb15,873
South Granville Water and Sewer AuthorityButner, NC49 of 5150.7 ppb19,219
Duncan Public Utilities Authority*Duncan, OK48 of 4850.6 ppb23,000
City of Topeka*Topeka, KS96 of 9649.8 ppb165,000
Lewisburg*Lewisburg, WV45 of 4549.7 ppb10,057
Bedford Regional Water Authority (brwa)Bedford, VA43 of 4349.5 ppb30,133
Wilderness WTPRuckersville, VA48 of 4849.5 ppb12,124
Appalachian State Univ WTPBoone, NC48 of 4849.0 ppb11,150
North Mercer Water DistrictSalvisa, KY40 of 4048.8 ppb12,884
McAlester PWA*Mcalester, OK48 of 4848.7 ppb17,783
El Dorado ID - Main*Placerville, CA98 of 9848.5 ppb112,000
Jonesborough Water DepartmentJohnson City, TN48 of 4848.5 ppb29,040
Albany Water Works*Albany, KY48 of 4848.2 ppb14,702
City of Asheboro*Asheboro, NC48 of 4848.1 ppb28,047
City of Paris*Paris, TX48 of 4847.9 ppb25,498
Bedford County UD*Shelbyville, TN49 of 4947.8 ppb18,722
City of Concord*Concord, NC96 of 9647.7 ppb87,654
Suisun-Solano Water AuthorityVacaville, CA3 of 347.2 ppb28,856
Orangeburg DPU*Orangeburg, SC48 of 4847.2 ppb49,906
North Monroe Et Al Water SystemWest Monroe, LA48 of 4847.1 ppb10,866
Rockwood Water System*Rockwood, TN48 of 4847.0 ppb11,594
Christian County Water District*Hopkinsville, KY48 of 4846.9 ppb15,841
Warren County Water DistrictBowling Green, KY113 of 11346.7 ppb74,096
Henderson County Water DistrictHenderson, KY48 of 4846.4 ppb19,008
Marshall County Water CorpMadill, OK48 of 4846.3 ppb14,717
Southern Okla Water CorpArdmore, OK35 of 4746.2 ppb11,250
Mohawk Correctional Facility*Rome, NY12 of 1246.1 ppb34,775
Buchanan County PSA*Vansant, VA48 of 4846.1 ppb19,205
East Cedar Creek FWSD BrookshireMabank, TX48 of 4846.1 ppb13,170
Rutland City Water Department*Rutland, VT48 of 4845.9 ppb18,500
Assumption Parish Waterworks District 1*Napoleonville, LA96 of 9645.8 ppb22,862
Tuskegee Utilities Board*Tuskegee, AL48 of 4845.7 ppb13,500

* This water utility supplies finished drinking water to at least one other water utility. The purchasing utility is not required to test for or report Haloacetic acids (HAA5), but it likely has the contaminant in its water supply.