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.
2015-2017:
7
states detected
375
utilities detected
12 million
people served
3
states over health guideline
44
utilities over health guideline
871,000
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
EWG Health Guideline 1 ppb
The EWG 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 | Utilities | People Served | Utilities | People Served | |||
| California | 28 | 380,007 | 89 | 4,626,559 | |||
| Massachusetts | 2 | 4,489 | 242 | 3,052,753 | |||
| New York | 14 | 486,510 | 35 | 2,306,067 | |||
| Virginia | 0 | 0 | 3 | 1,289,499 | |||
| District Of Columbia | 0 | 0 | 3 | 648,882 | |||
| North Carolina | 0 | 0 | 1 | 128,800 | |||
| Rhode Island | 0 | 0 | 1 | 8,969 | |||
| Vermont | 0 | 0 | 1 | 60 | |||
Filtering technologies that reduce perchlorate
Reverse Osmosis
Ion Exchange
Utilities with the highest amounts of perchlorate, 2015-2017
| Utility | Location | Tests | Average level | People served |
|---|---|---|---|---|
| Kern Valley State Prison | Delano, CA | 2 of 2 | 17.4 ppb | 5,300 |
| La Verne WD | La Verne, CA | 180 of 230 | 6.63 ppb | 32,230 |
| Riverside Water District | Oakdale, NY | 3 of 3 | 5.10 ppb | 2,050 |
| Riverhead WD* | Riverhead, NY | 3 of 3 | 5.10 ppb | 35,000 |
| Castaic Lake Water Agency* | Santa Clarita, CA | 687 of 2,572 | 4.55 ppb | 0 |
| Marygold Mutual Water Company | Bloomington, CA | 8 of 11 | 4.06 ppb | 3,449 |
| City Of Etna | Etna, CA | 1 of 1 | 4.00 ppb | 769 |
| Tierra Buena Mobile Home Park #1 | Marysville, CA | 10 of 12 | 3.71 ppb | 50 |
| Westbury WD | Westbury, NY | 29 of 45 | 3.52 ppb | 20,500 |
| Locust Valley Water District | Locust Valley, NY | 14 of 19 | 3.42 ppb | 7,500 |
| Fairview Water Company LLC | Tehachapi, CA | 53 of 130 | 3.20 ppb | 240 |
| Page Avenue Mutual Water Company | Fullerton, CA | 9 of 13 | 3.13 ppb | 115 |
| Plainview WD | Plainview, NY | 309 of 426 | 2.90 ppb | 35,000 |
| Loma Linda Power Plant | Loma Linda, CA | 17 of 24 | 2.67 ppb | 10,500 |
| Hynes Estates Mutual Water Company | Anaheim, CA | 9 of 18 | 2.57 ppb | 120 |
| Santa Ynez Roblar Mobile Home Park | La Canada, CA | 1 of 1 | 2.50 ppb | 45 |
| Bethpage WD | Bethpage, NY | 288 of 473 | 2.47 ppb | 33,000 |
| Palms River Resort | Hemet, CA | 1 of 2 | 2.35 ppb | 200 |
| Ontario Municipal Utilities Company | Ontario, CA | 43 of 44 | 2.27 ppb | 167,382 |
| Town of Hempstead Water Department | East Meadow, NY | 39 of 64 | 2.21 ppb | 110,000 |
| Las Flores Water Company | Altadena, CA | 133 of 305 | 2.08 ppb | 4,500 |
| City of Chino | Chino, CA | 129 of 615 | 2.07 ppb | 18,907 |
| Stallion Springs Community Services District | Tehachapi, CA | 40 of 120 | 2.02 ppb | 2,488 |
| Lemon Cove Water Company | Lemon Cove, CA | 1 of 1 | 2.00 ppb | 200 |
| Saticoy Country Club-city Of Ventura | Ventura, CA | 2 of 5 | 2.00 ppb | 150 |
| Hicksville WD | Hicksville, NY | 363 of 470 | 1.88 ppb | 48,000 |
| Glenwood Water District | Glenwood Landing, NY | 3 of 4 | 1.88 ppb | 1,000 |
| Roslyn WD* | Roslyn, NY | 3 of 4 | 1.88 ppb | 18,000 |
| South Huntington Water Department | South Huntington, NY | 3 of 3 | 1.68 ppb | 81,760 |
| Jericho Water District | Syosset, NY | 62 of 111 | 1.64 ppb | 58,000 |
| Glen Cove City | Glen Cove, NY | 27 of 33 | 1.58 ppb | 28,000 |
| Calif State Polytechnical Univ - Pomona | Pomona, CA | 61 of 238 | 1.55 ppb | 24,880 |
| Western MWD (Arlington)* | Riverside, CA | 29 of 102 | 1.50 ppb | 0 |
| Carpinteria Valley Water District | Carpinteria, CA | 1 of 2 | 1.50 ppb | 16,050 |
| Valencia Heights Water Company | West Covina, CA | 56 of 247 | 1.34 ppb | 5,500 |
| West San Martin Water Works Inc. | San Martin, CA | 42 of 85 | 1.30 ppb | 1,403 |
| San Martin County Water District | Morgan Hill, CA | 28 of 95 | 1.22 ppb | 614 |
| Herring Cove Condominiums Trust | Plymouth, MA | 28 of 36 | 1.19 ppb | 25 |
| Redlands City | Redlands, CA | 354 of 772 | 1.16 ppb | 80,000 |
| Sturbridge Water Department | Sturbridge, MA | 116 of 121 | 1.16 ppb | 4,464 |
| Yerba Buena Water Company | Paso Robles, CA | 1 of 7 | 1.14 ppb | 690 |
| Yuima Municipal Water District Ida | Pauma Valley, CA | 43 of 209 | 1.08 ppb | 400 |
| Oyster Bay Water District | Oyster Bay, NY | 6 of 13 | 1.01 ppb | 8,700 |
| Garden City | Garden City, NY | 16 of 42 | 0.986 ppb | 46,000 |
| Charlton Street Apartments | Oxford, MA | 9 of 9 | 0.954 ppb | 33 |
| Azusa Light and Water | Azusa, CA | 47 of 397 | 0.860 ppb | 110,000 |
| WA of Great Neck North | Great Neck, NY | 17 of 50 | 0.790 ppb | 31,400 |
| City of Upland* | Upland, CA | 11 of 66 | 0.789 ppb | 78,791 |
| Yuima Municipal Water District* | Pauma Valley, CA | 2 of 11 | 0.782 ppb | 260 |
| Rubidoux Community SD | Rubidoux, CA | 20 of 120 | 0.751 ppb | 26,150 |
* 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.
| Utility | Location | Tests | Average level | People served |
|---|---|---|---|---|
| La Verne WD | La Verne, CA | 180 of 230 | 6.63 ppb | 32,230 |
| Riverhead WD* | Riverhead, NY | 3 of 3 | 5.10 ppb | 35,000 |
| Westbury WD | Westbury, NY | 29 of 45 | 3.52 ppb | 20,500 |
| Plainview WD | Plainview, NY | 309 of 426 | 2.90 ppb | 35,000 |
| Loma Linda Power Plant | Loma Linda, CA | 17 of 24 | 2.67 ppb | 10,500 |
| Bethpage WD | Bethpage, NY | 288 of 473 | 2.47 ppb | 33,000 |
| Ontario Municipal Utilities Company | Ontario, CA | 43 of 44 | 2.27 ppb | 167,382 |
| Town of Hempstead Water Department | East Meadow, NY | 39 of 64 | 2.21 ppb | 110,000 |
| City of Chino | Chino, CA | 129 of 615 | 2.07 ppb | 18,907 |
| Hicksville WD | Hicksville, NY | 363 of 470 | 1.88 ppb | 48,000 |
| Roslyn WD* | Roslyn, NY | 3 of 4 | 1.88 ppb | 18,000 |
| South Huntington Water Department | South Huntington, NY | 3 of 3 | 1.68 ppb | 81,760 |
| Jericho Water District | Syosset, NY | 62 of 111 | 1.64 ppb | 58,000 |
| Glen Cove City | Glen Cove, NY | 27 of 33 | 1.58 ppb | 28,000 |
| Calif State Polytechnical Univ - Pomona | Pomona, CA | 61 of 238 | 1.55 ppb | 24,880 |
| Carpinteria Valley Water District | Carpinteria, CA | 1 of 2 | 1.50 ppb | 16,050 |
| Redlands City | Redlands, CA | 354 of 772 | 1.16 ppb | 80,000 |
| Garden City | Garden City, NY | 16 of 42 | 0.986 ppb | 46,000 |
| Azusa Light and Water | Azusa, CA | 47 of 397 | 0.860 ppb | 110,000 |
| WA of Great Neck North | Great Neck, NY | 17 of 50 | 0.790 ppb | 31,400 |
| City of Upland* | Upland, CA | 11 of 66 | 0.789 ppb | 78,791 |
| Rubidoux Community SD | Rubidoux, CA | 20 of 120 | 0.751 ppb | 26,150 |
| Mineola | Mineola, NY | 23 of 64 | 0.694 ppb | 20,600 |
| Manhasset Lakeville WD* | Great Neck, NY | 3 of 9 | 0.676 ppb | 44,600 |
| Falmouth Water Department | Falmouth, MA | 9 of 17 | 0.669 ppb | 77,500 |
| West Springfield Dpw Water Division | West Springfield, MA | 1 of 1 | 0.563 ppb | 28,391 |
| San Bernardino City* | San Bernardino, CA | 509 of 964 | 0.561 ppb | 188,931 |
| Golden State Water Company - West Orange | Anaheim, CA | 7 of 63 | 0.560 ppb | 114,016 |
| Cal/Am Water Company - San Marino | Rosemead, CA | 22 of 184 | 0.559 ppb | 40,804 |
| City of Corona* | Corona, CA | 40 of 488 | 0.532 ppb | 155,896 |
| Smithtown WD | Kings Park, NY | 3 of 3 | 0.525 ppb | 19,635 |
| Suffolk County Water Authority* | Oakdale, NY | 3 of 3 | 0.525 ppb | 1,100,000 |
| St James WD | St James, NY | 3 of 3 | 0.525 ppb | 10,587 |
| Water Authority of Western Nassau | Floral Park, NY | 4 of 11 | 0.518 ppb | 120,000 |
| Monrovia Water Department | Monrovia, CA | 31 of 329 | 0.516 ppb | 36,590 |
| Monte Vista Water District* | Montclair, CA | 44 of 443 | 0.505 ppb | 54,460 |
| Arlington County* | Arlington, VA | 69 of 71 | 0.465 ppb | 215,000 |
| D.C. Water and Sewer Authority* | Washington, DC | 69 of 71 | 0.465 ppb | 632,323 |
| Rockport Water Department | Rockport, MA | 7 of 7 | 0.455 ppb | 10,000 |
| Jurupa Community Services District* | Jurupa Valley, CA | 10 of 114 | 0.409 ppb | 106,907 |
| Camrosa Water District | Camarillo, CA | 1 of 5 | 0.400 ppb | 30,000 |
| Suburban Water Systems - San Jose Hills | Covina, CA | 10 of 110 | 0.396 ppb | 162,031 |
| City of Santa Ana | Santa Ana, CA | 7 of 79 | 0.392 ppb | 329,815 |
| Tewksbury Water Department | Tewksbury, MA | 3 of 3 | 0.373 ppb | 29,855 |
| West Valley Water District* | Rialto, CA | 44 of 585 | 0.364 ppb | 72,647 |
| Gardner Water Department | Gardner, MA | 6 of 6 | 0.325 ppb | 19,133 |
| Swansea Water District | Swansea, MA | 18 of 18 | 0.320 ppb | 17,358 |
| New York American Water - Sea Cliff | Merrick, NY | 10 of 38 | 0.300 ppb | 13,400 |
| Lowell Regional Water Utility* | Lowell, MA | 3 of 3 | 0.293 ppb | 106,519 |
| Billerica Water Works | Billerica, MA | 3 of 3 | 0.284 ppb | 40,243 |
* 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.