Menu

EWG's Tap Water Database

Donate

Perchlorate

Status: No national drinking water standard exists

 

Perchlorate, a component of rocket fuel, occurs both naturally and as a synthetic chemical. Ingested perchlorate interferes with thyroid function. Exposure to perchlorate during pregnancy and childhood can impair cognitive development. Read More.

According to the EPA, perchlorate likely contaminates the water of more than 16 million Americans. Perchlorate interferes with iodine uptake in the thyroid, which can result in reduced thyroid hormones and an impact on metabolism, physical development and cognitive development. Children and developing fetuses are the most at risk from perchlorate contamination.

Perchlorate is the only unregulated contaminant for which the EPA has attempted to set a federal drinking water standard since 1996. However, the agency has yet to propose a draft limit for this contaminant. Perchlorate in drinking water is regulated in Arizona, California, Massachusetts, New Jersey, New York and Texas. California set a public health goal of 1 part per billion for perchlorate in 2015.

Click here to read more about perchlorate.

2015:

FOUND
FOUND ABOVE HEALTH GUIDELINES

4

states detected

206

utilities detected

8.3 million

people served

3

states over health guideline

39

utilities over health guideline

924,000

people served over health guideline

Health concerns for perchlorate

Hormone disruption

Harm to fetal growth and child development

State and national drinking water standards and health guidelines

Health Guideline 1 ppb

The health guideline of 1 ppb for perchlorate was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against hormone disruption.

ppb = parts per billion.

States reporting perchlorate in drinking water

UTILITIES REPORTING ABOVE HEALTH GUIDELINES UTILITIES WITH CONTAMINATION
State UtilitiesPeople Served UtilitiesPeople Served
California21363,028442,425,308
Massachusetts24,6171292,037,267
New York16556,670281,964,291
Virginia0021,269,000
District Of Columbia003644,822
MORE
LESS

Utilities with the highest amounts of perchlorate, 2015

ALL UTILITIES
LARGE UTILITIES
UtilityLocationTestsAverage levelPeople served
Locust Valley Water DistrictLocust Valley, NY2 of 28.55 ppb7,500
Riverhead WD*Riverhead, NY1 of 16.75 ppb37,050
La Verne WDLa Verne, CA57 of 735.85 ppb32,230
Marygold Mutual Water CompanyBloomington, CA2 of 24.90 ppb3,449
Castaic Lake Water Agency*Santa Clarita, CA231 of 8654.64 ppb0
Fairview Water Company LLCTehachapi, CA10 of 183.79 ppb240
Tierra Buena Mobile Home Park #1Marysville, CA3 of 43.58 ppb50
Plainview WDPlainview, NY94 of 1243.26 ppb35,000
Town of Hempstead Water DepartmentEast Meadow, NY15 of 232.92 ppb110,000
Westbury WDWestbury, NY6 of 122.88 ppb20,500
Boe Del Heights Mutual WaterIndio, CA4 of 82.53 ppb325
Bethpage WDBethpage, NY96 of 1552.44 ppb33,000
City of ChinoChino, CA47 of 2372.40 ppb18,907
Stallion Springs Community Services DistrictTehachapi, CA18 of 482.40 ppb2,488
Ontario Municipal Utilities CompanyOntario, CA14 of 142.29 ppb167,382
Glen Cove CityGlen Cove, NY11 of 112.18 ppb28,000
Roslyn WD*Roslyn, NY2 of 22.15 ppb18,000
Hicksville WDHicksville, NY88 of 982.12 ppb47,810
Herring Cove Condominiums TrustPlymouth, MA18 of 192.10 ppb25
Loma Linda Power PlantLoma Linda, CA7 of 121.97 ppb10,500
Las Flores Water CompanyAltadena, CA44 of 1081.94 ppb4,500
South Huntington Water DepartmentSouth Huntington, NY1 of 11.90 ppb81,760
Jericho Water DistrictSyosset, NY17 of 351.50 ppb58,000
Carpinteria Valley Water DistrictCarpinteria, CA1 of 21.50 ppb16,050
Sturbridge Water DepartmentSturbridge, MA41 of 421.40 ppb4,592
Valencia Heights Water CompanyWest Covina, CA21 of 861.34 ppb5,500
Page Avenue Mutual Water CompanyFullerton, CA1 of 41.28 ppb115
San Martin County Water DistrictMorgan Hill, CA7 of 231.27 ppb614
Valley Water CompanyLa Canada Flintridge, CA16 of 561.26 ppb9,900
Redlands CityRedlands, CA139 of 3041.25 ppb80,000

* 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 Perchlorate, but it likely has the contaminant in its water supply.

MORE
LESS
UtilityLocationTestsAverage levelPeople served
Riverhead WD*Riverhead, NY1 of 16.75 ppb37,050
La Verne WDLa Verne, CA57 of 735.85 ppb32,230
Plainview WDPlainview, NY94 of 1243.26 ppb35,000
Town of Hempstead Water DepartmentEast Meadow, NY15 of 232.92 ppb110,000
Westbury WDWestbury, NY6 of 122.88 ppb20,500
Bethpage WDBethpage, NY96 of 1552.44 ppb33,000
City of ChinoChino, CA47 of 2372.40 ppb18,907
Ontario Municipal Utilities CompanyOntario, CA14 of 142.29 ppb167,382
Glen Cove CityGlen Cove, NY11 of 112.18 ppb28,000
Roslyn WD*Roslyn, NY2 of 22.15 ppb18,000
Hicksville WDHicksville, NY88 of 982.12 ppb47,810
Loma Linda Power PlantLoma Linda, CA7 of 121.97 ppb10,500
South Huntington Water DepartmentSouth Huntington, NY1 of 11.90 ppb81,760
Jericho Water DistrictSyosset, NY17 of 351.50 ppb58,000
Carpinteria Valley Water DistrictCarpinteria, CA1 of 21.50 ppb16,050
Redlands CityRedlands, CA139 of 3041.25 ppb80,000
MineolaMineola, NY12 of 181.25 ppb20,600
Garden CityGarden City, NY6 of 161.18 ppb25,000
WA of Great Neck NorthGreat Neck, NY4 of 121.12 ppb31,400
City of Upland*Upland, CA3 of 160.969 ppb78,791
Water Authority of Western NassauFloral Park, NY4 of 60.950 ppb120,000
San Bernardino City*San Bernardino, CA212 of 2770.932 ppb188,931
Monte Vista Water District*Montclair, CA8 of 470.898 ppb54,460
Azusa Light and WaterAzusa, CA16 of 1360.826 ppb110,000
Monrovia Water DepartmentMonrovia, CA16 of 1200.814 ppb36,590
West Valley Water District*Rialto, CA37 of 2320.801 ppb72,647
Golden State Water Company - West OrangeAnaheim, CA3 of 190.705 ppb114,016
Rubidoux Community SD*Rubidoux, CA5 of 360.664 ppb26,150
HempsteadHempstead, NY1 of 40.650 ppb56,000
Falmouth Water DepartmentFalmouth, MA4 of 70.643 ppb77,500

* 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 Perchlorate, but it likely has the contaminant in its water supply.

MORE
LESS