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.
2017-2019:
9
states detected
379
utilities detected
12 million
people served
4
states over health guideline
50
utilities over health guideline
1.5 million
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 | 35 | 706,248 | 83 | 3,948,334 | |||
| Massachusetts | 2 | 128 | 244 | 2,881,654 | |||
| New York | 11 | 458,810 | 31 | 2,206,558 | |||
| Nevada | 2 | 330,581 | 7 | 2,171,812 | |||
| Virginia | 0 | 0 | 3 | 185,808 | |||
| North Carolina | 0 | 0 | 1 | 153,202 | |||
| Kansas | 0 | 0 | 8 | 145,400 | |||
| 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, 2017-2019
| 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 | 377 of 478 | 6.99 ppb | 32,230 |
| Riverhead WD* | Riverhead, NY | 4 of 4 | 5.64 ppb | 35,000 |
| Riverside Water District | Hauppauge, NY | 4 of 4 | 5.64 ppb | 2,050 |
| Lsid - Tonyville | Lindsay, CA | 13 of 14 | 5.36 ppb | 500 |
| Locust Valley Water District | Locust Valley, NY | 33 of 48 | 4.77 ppb | 7,500 |
| Stallion Springs Community Services District | Tehachapi, CA | 107 of 206 | 4.52 ppb | 2,488 |
| Castaic Lake Water Agency* | Santa Clarita, CA | 1309 of 5,042 | 4.48 ppb | 0 |
| Marygold Mutual Water Company | Bloomington, CA | 34 of 41 | 4.04 ppb | 3,449 |
| City Of Etna | Etna, CA | 1 of 1 | 4.00 ppb | 769 |
| Tierra Buena Mobile Home Park #1 | Marysville, CA | 19 of 24 | 3.53 ppb | 50 |
| Page Avenue Mutual Water Company | Fullerton, CA | 20 of 27 | 3.45 ppb | 115 |
| Westbury WD | Westbury, NY | 62 of 97 | 3.19 ppb | 20,500 |
| Hynes Estates Mutual Water Company | Anaheim, CA | 20 of 33 | 2.92 ppb | 120 |
| Plainview WD | Plainview, NY | 556 of 792 | 2.90 ppb | 35,000 |
| Touisset Point Water Trust | Warren, RI | 2 of 2 | 2.83 ppb | 225 |
| Fairview Water Company LLC | Tehachapi, CA | 68 of 198 | 2.63 ppb | 240 |
| Lincoln Avenue Water Company | Altadena, CA | 95 of 484 | 2.45 ppb | 16,000 |
| Bethpage WD | Bethpage, NY | 548 of 896 | 2.42 ppb | 33,000 |
| Calif State Polytechnical Univ - Pomona | Pomona, CA | 192 of 543 | 2.32 ppb | 24,880 |
| City of Chino | Chino, CA | 275 of 1,191 | 2.25 ppb | 18,907 |
| Town of Hempstead Water Department | East Meadow, NY | 70 of 119 | 2.14 ppb | 110,000 |
| Northbrook Village II | Berlin, MA | 12 of 14 | 2.13 ppb | 80 |
| Rancho Borromeo Mws | Prunedale, CA | 1 of 2 | 2.05 ppb | 100 |
| Santa Ynez Roblar Mobile Home Park | La Canada, CA | 2 of 2 | 2.00 ppb | 45 |
| Camp Owen Water System | Kernville, CA | 1 of 6 | 2.00 ppb | 225 |
| Western MWD (Arlington)* | Riverside, CA | 79 of 217 | 1.96 ppb | 0 |
| City of Henderson | Henderson, NV | 21 of 21 | 1.94 ppb | 321,781 |
| Hicksville WD | Hicksville, NY | 755 of 967 | 1.93 ppb | 48,000 |
| Ontario Municipal Utilities Company | Ontario, CA | 69 of 97 | 1.81 ppb | 167,382 |
| Las Flores Water Company | Altadena, CA | 236 of 616 | 1.80 ppb | 4,500 |
| Jericho Water District | Syosset, NY | 132 of 240 | 1.73 ppb | 58,000 |
| South Huntington Water Department | South Huntington, NY | 5 of 5 | 1.72 ppb | 81,760 |
| Loma Linda Power Plant | Loma Linda, CA | 26 of 58 | 1.70 ppb | 10,500 |
| Saticoy Country Club-city Of Ventura | Ventura, CA | 2 of 6 | 1.67 ppb | 150 |
| University of Rhode Island | Kingston, RI | 4 of 5 | 1.61 ppb | 19,354 |
| Northbrook Village I / Berlin Ret. | Berlin, MA | 15 of 23 | 1.50 ppb | 48 |
| Glen Cove City | Glen Cove, NY | 51 of 69 | 1.42 ppb | 28,000 |
| Rainbird Valley Mutual Water Company | Weldon, CA | 1 of 3 | 1.40 ppb | 188 |
| West San Martin Water Works Inc. | San Martin, CA | 75 of 151 | 1.37 ppb | 1,403 |
| Yuima Municipal Water District Ida | Pauma Valley, CA | 102 of 423 | 1.30 ppb | 400 |
| Herring Cove Condominiums Trust | Plymouth, MA | 44 of 54 | 1.27 ppb | 25 |
| Cal/Am Water Company - San Marino | Rosemead, CA | 115 of 473 | 1.27 ppb | 40,804 |
| Redlands City* | Redlands, CA | 785 of 1,690 | 1.26 ppb | 80,000 |
| Rocky Comfort Mutual Water Company | Mentone, CA | 785 of 1,690 | 1.26 ppb | 160 |
| San Martin County Water District | Morgan Hill, CA | 56 of 203 | 1.19 ppb | 614 |
| Garlen Court Ws | Salinas, CA | 1 of 5 | 1.18 ppb | 69 |
| Palms River Resort | Hemet, CA | 1 of 4 | 1.18 ppb | 200 |
| Valencia Heights Water Company | West Covina, CA | 98 of 497 | 1.17 ppb | 5,500 |
| Big Bend Water District | Las Vegas, NV | 26 of 26 | 1.12 ppb | 8,800 |
* 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 | 377 of 478 | 6.99 ppb | 32,230 |
| Riverhead WD* | Riverhead, NY | 4 of 4 | 5.64 ppb | 35,000 |
| Westbury WD | Westbury, NY | 62 of 97 | 3.19 ppb | 20,500 |
| Plainview WD | Plainview, NY | 556 of 792 | 2.90 ppb | 35,000 |
| Lincoln Avenue Water Company | Altadena, CA | 95 of 484 | 2.45 ppb | 16,000 |
| Bethpage WD | Bethpage, NY | 548 of 896 | 2.42 ppb | 33,000 |
| Calif State Polytechnical Univ - Pomona | Pomona, CA | 192 of 543 | 2.32 ppb | 24,880 |
| City of Chino | Chino, CA | 275 of 1,191 | 2.25 ppb | 18,907 |
| Town of Hempstead Water Department | East Meadow, NY | 70 of 119 | 2.14 ppb | 110,000 |
| City of Henderson | Henderson, NV | 21 of 21 | 1.94 ppb | 321,781 |
| Hicksville WD | Hicksville, NY | 755 of 967 | 1.93 ppb | 48,000 |
| Ontario Municipal Utilities Company | Ontario, CA | 69 of 97 | 1.81 ppb | 167,382 |
| Jericho Water District | Syosset, NY | 132 of 240 | 1.73 ppb | 58,000 |
| South Huntington Water Department | South Huntington, NY | 5 of 5 | 1.72 ppb | 81,760 |
| Loma Linda Power Plant | Loma Linda, CA | 26 of 58 | 1.70 ppb | 10,500 |
| University of Rhode Island | Kingston, RI | 4 of 5 | 1.61 ppb | 19,354 |
| Glen Cove City | Glen Cove, NY | 51 of 69 | 1.42 ppb | 28,000 |
| Cal/Am Water Company - San Marino | Rosemead, CA | 115 of 473 | 1.27 ppb | 40,804 |
| Redlands City* | Redlands, CA | 785 of 1,690 | 1.26 ppb | 80,000 |
| Roslyn WD* | Roslyn, NY | 6 of 14 | 1.05 ppb | 18,000 |
| Garden City | Garden City, NY | 27 of 75 | 0.919 ppb | 46,000 |
| Mineola | Mineola, NY | 47 of 111 | 0.858 ppb | 20,600 |
| City of Corona* | Corona, CA | 165 of 1,182 | 0.853 ppb | 155,896 |
| Lakeside WD* | Lakeside, CA | 2 of 18 | 0.811 ppb | 42,200 |
| WA of Great Neck North | Great Neck, NY | 25 of 84 | 0.707 ppb | 31,400 |
| Rubidoux Community SD | Rubidoux, CA | 28 of 206 | 0.618 ppb | 26,150 |
| Boulder City* | Boulder City, NV | 141 of 141 | 0.603 ppb | 15,000 |
| Carpinteria Valley Water District | Carpinteria, CA | 1 of 5 | 0.600 ppb | 16,050 |
| City of Upland* | Upland, CA | 17 of 140 | 0.579 ppb | 78,791 |
| Suburban Water Systems - San Jose Hills | Covina, CA | 27 of 205 | 0.572 ppb | 162,031 |
| Manhasset Lakeville WD* | Great Neck, NY | 8 of 23 | 0.534 ppb | 44,600 |
| St James WD | St James, NY | 4 of 4 | 0.530 ppb | 10,587 |
| Smithtown WD | Kings Park, NY | 4 of 4 | 0.530 ppb | 19,635 |
| Suffolk County Water Authority* | Bayshore, NY | 4 of 4 | 0.530 ppb | 1,100,000 |
| Monrovia Water Department | Monrovia, CA | 60 of 688 | 0.474 ppb | 36,590 |
| Golden State Water Company - West Orange | Anaheim, CA | 12 of 125 | 0.466 ppb | 114,016 |
| Falmouth Water Department | Falmouth, MA | 13 of 36 | 0.459 ppb | 77,500 |
| San Bernardino City* | San Bernardino, CA | 807 of 1,925 | 0.457 ppb | 188,931 |
| Water Authority of Western Nassau | New Hyde Park, NY | 7 of 24 | 0.408 ppb | 120,000 |
| University of Kansas | Lawrence, KS | 8 of 8 | 0.398 ppb | 35,000 |
| City of Lawrence* | Lawrence, KS | 8 of 8 | 0.398 ppb | 97,286 |
| New York American Water - Sea Cliff | Merrick, NY | 24 of 80 | 0.391 ppb | 13,400 |
| Pasadena* | Pasadena, CA | 105 of 1,392 | 0.372 ppb | 165,740 |
| Tewksbury Water Department | Tewksbury, MA | 6 of 6 | 0.352 ppb | 30,435 |
| Swansea Water District | Swansea, MA | 34 of 34 | 0.350 ppb | 17,358 |
| Rockport Water Department | Rockport, MA | 9 of 10 | 0.348 ppb | 10,000 |
| Jurupa Community Services District* | Jurupa Valley, CA | 17 of 234 | 0.329 ppb | 106,907 |
| Hempstead | Hempstead, NY | 9 of 45 | 0.329 ppb | 56,000 |
| Lowell Regional Water Utility* | Lowell, MA | 6 of 6 | 0.290 ppb | 106,519 |
| Billerica Water Works | Billerica, MA | 6 of 6 | 0.286 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.