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e-CFR data is current as of January 14, 2021

Title 40Chapter ISubchapter DPart 141Subpart O → Appendix


Title 40: Protection of Environment
PART 141—NATIONAL PRIMARY DRINKING WATER REGULATIONS
Subpart O—Consumer Confidence Reports


Appendix A to Subpart O of Part 141—Regulated Contaminants

Contaminant (units)Traditional MCL in mg/LTo convert for CCR, multiply byMCL in CCR unitsMCLGMajor sources in drinking waterHealth effects language
Microbiological contaminants:
Total Coliform Bacteria †MCL (systems that collect ≥40 samples/month) 5% of monthly samples are positive; (systems that collect <40 samples/month) 1 positive monthly sampleMCL (systems that collect ≥40 samples/month) 5% of monthly samples are positive; (systems that collect <40 samples/month) 1 positive monthly sample.0Naturally present in the environmentColiforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially-harmful, bacteria may be present. Coliforms were found in more samples than allowed and this was a warning of potential problems.
Total Coliform Bacteria ‡TTTTN/ANaturally present in the environmentUse language found in §141.153(h)(7)(i)(A)
Fecal coliform and E. coli000Human and animal fecal wasteFecal coliforms and E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems.
E. coliRoutine and repeat samples are total coliform-positive and either is E. coli-positive or system fails to take repeat samples following E. coli-positive routine sample or system fails to analyze total coliform-positive repeat sample for E. coliRoutine and repeat samples are total coliform-positive and either is E. coli-positive or system fails to take repeat samples following E. coli-positive routine sample or system fails to analyze total coliform-positive repeat sample for E. coli0Human and animal fecal wasteE. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Human pathogens in these wastes can cause short-term effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a greater health risk for infants, young children, the elderly, and people with severely-compromised immune systems.
Fecal Indicators (enterococci or coliphage)TTTTN/AHuman and animal fecal wasteFecal indicators are microbes whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term health effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems.
Total organic carbon (ppm)TTTTN/ANaturally present in the environmentTotal organic carbon (TOC) has no health effects. However, total organic carbon provides a medium for the formation of disinfection by products. These byproducts include trihalomethanes (THMs) and haloacetic acids (HAAs). Drinking water containing these byproducts in excess of the MCL may lead to adverse health effects, liver or kidney problems, or nervous system effects, and may lead to an increased risk of getting cancer.
Turbidity (NTU)TTTTN/ASoil runoffTurbidity has no health effects. However, turbidity can interfere with disinfection and provide a medium for microbial growth. Turbidity may indicate the presence of disease-causing organisms. These organisms include bacteria, viruses, and parasites that can cause symptoms such as nausea, cramps, diarrhea and associated headaches.
Radioactive contaminants:
Beta/photon emitters (mrem/yr)4 mrem/yr40Decay of natural and man-made depositsCertain minerals are radioactive and may emit forms of radiation known as photons and beta radiation. Some people who drink water containing beta particle and photon radioactivity in excess of the MCL over many years may have an increased risk of getting cancer.
Alpha emitters (pCi/L)15 pCi/L150Erosion of natural depositsCertain minerals are radioactive and may emit a form of radiation known as alpha radiation. Some people who drink water containing alpha emitters in excess of the MCL over many years may have an increased risk of getting cancer.
Combined radium (pCi/L)5 pCi/L50Erosion of natural depositsSome people who drink water containing radium-226 or -228 in excess of the MCL over many years may have an increased risk of getting cancer.
Uranium (pCi/L)30 µg/L300Erosion of natural depositsSome people who drink water containing uranium in excess of the MCL over many years may have an increased risk of getting cancer and kidney toxicity.
Inorganic contaminants:
Antimony (ppb).006100066Discharge from petroleum refineries; fire retardants; ceramics; electronics; solderSome people who drink water containing antimony well in excess of the MCL over many years could experience increases in blood cholesterol and decreases in blood sugar.
Arsenic (ppb)10.0101000110.10Erosion of natural deposits; Runoff from orchards; Runoff from glass and electronics production wastesSome people who drink water containing arsenic in excess of the MCL over many years could experience skin damage or problems with their circulatory system, and may have an increased risk of getting cancer.
Asbestos (MFL)7 MFL77Decay of asbestos cement water mains; Erosion of natural depositsSome people who drink water containing asbestos in excess of the MCL over many years may have an increased risk of developing benign intestinal polyps.
Barium (ppm)222Discharge of drilling wastes; Discharge from metal refineries; Erosion of natural depositsSome people who drink water containing barium in excess of the MCL over many years could experience an increase in their blood pressure.
Beryllium (ppb).004100044Discharge from metal refineries and coal-burning factories; Discharge from electrical, aerospace, and defense industriesSome people who drink water containing beryllium well in excess of the MCL over many years could develop intestinal lesions
Bromate (ppb).0101000100By-product of drinkig water disinfectionSome people who drink water of containing bromate in excess of the MCL over many years may have an increased risk of getting cancer.
Cadmium (ppb).005100055Corrosion of galvanized pipes; Erosion of natural deposits; Discharge from metal refineries; Runoff from waste batteries and paintsSome people who drink water containing cadmium in excess of the MCL over many years could experience kidney damage.
Chloramines (ppm)MRDL = 4MRDL = 4MRDLG = 4Water additive used to control microbesSome people who use water containing chloramines well in excess of the MRDL could experience irritating effects to their eyes and nose. Some people who drink water containing chloramines well in excess of the MRDL could experience stomach discomfort or anemia.
Chlorine (ppm)MRDL = 4MRDL = 4MRDLG = 4Water additive used to control microbesSome people who use water containing chlorine well in excess of the MRDL could experience irritating effects to their eyes and nose. Some people who drink water containing chlorine well in excess of the MRDL could experience stomach discomfort.
Chlorine dioxide (ppb)MRDL = .81000MRDL = 800MRDLG = 800Water additive used to control micorbesSome infants and young children who drink water chlorine dioxide in excess of the MRDL could experience nervous system effects. Similar effects may occur in fetuses of pregnant women who drink water containing chlorine dioxide in excess of the MRDL. Some people may experience anemia.
Chlorite (ppm)110.8By-product of drinking water disinfectionSome infants and young children who drink water containing chlorite in excess of the MCL could experience nervous system effects. Similar effects may occur in fetuses of pregnant women who drink water containing chlorite in excess of the MCL. Some people may experience anemia.
Chromium (ppb).11000100100Discharge from steel and pulp mills; Erosion of natural depositsSome people who use water containing chromium well in excess of the MCL over many years could experience allergic dermatitis.
Copper (ppm)AL = 1.3AL = 1.31.3Corrosion of household plumbing systems; Erosion of natural depositsCopper is an essential nutrient, but some people who drink water containing copper in excess of the action level over a relatively short amount of time could experience gastrointestinal distress. Some people who drink water containing copper in excess of the action level over many years could suffer liver or kidney damage. People with Wilson's disease should consult their personal doctor.
Cyanide (ppb).21000200200Discharge from steel/metal factories; Discharge from plastic and fertilizer factoriesSome people who drink water containing cyanide well in excess of the MCL over many years could experience nerve damage or problems with their thyroid.
Fluoride (ppm)444Erosion of natural deposits; Water additive which promotes strong teeth; Discharge from fertilizer and aluminum factoriesSome people who drink water containing fluoride in excess of the MCL over many years could get bone disease, including pain and tenderness of the bones. Fluoride in drinking water at half the MCL or more may cause mottling of children's teeth, usually in children less than nine years old. Mottling, also known as dental fluorosis, may include brown staining and/or pitting of the teeth, and occurs only in developing teeth before they erupt from the gums.
Lead (ppb)AL = .0151000AL = 150Corrosion of household plumbing systems; Erosion of natural depositsInfants and children who drink water containing lead in excess of the action level could experience delays in their physical or mental development. Children could show slight deficits in attention span and learning abilities. Adults who drink this water over many years could develop kidney problems or high blood pressure.
Mercury [inorganic] (ppb).002100022Erosion of natural deposits; Dis charge from refineries and factories; Runoff from landfills; Runoff from croplandSome people who drink water containing inorganic mercury well in excess of the MCL over many years could experience kidney damage.
Nitrate (ppm)101010Runoff from fertilizer use; Leaching from septic tanks, sew age; Erosion of natural depositsInfants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue baby syndrome.
Nitrite (ppm)111Runoff from fertilizer use; Leaching from septic tanks, sew age; Erosion of natural depositsInfants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue baby syndrome.
Selenium (ppb).0510005050Discharge from petroleum and metal refineries; Erosion of natural deposits; Discharge from minesSelenium is an essential nutrient. However, some people who drink water containing selenium in excess of the MCL over many years could experience hair or fingernail losses, numbness in fingers or toes, or problems with their circulation.
Thallium (ppb).002100020.5Leaching from ore-processing sites; Discharge from electronics, glass, and drug factoriesSome people who drink water containing thallium in excess of the MCL over many years could experience hair loss, changes in their blood, or problems with their kidneys, intestines, or liver.
Synthetic organic contaminants including pesticides and herbicides:
2,4-D (ppb).0710007070Runoff from herbicide used on row cropsSome people who drink water containing the weed killer 2,4-D well in excess of the MCL over many years could experience problems with their kidneys, liver, or adrenal glands.
2,4,5-TP [Silvex](ppb).0510005050Residue of banned herbicideSome people who drink water containing silvex in excess of the MCL over many years could experience liver problems.
AcrylamideTTTT0Added to water during sewage/wastewater treatmentSome people who drink water containing high levels of acrylamide over a long period of time could have problems with their nervous system or blood, and may have an increased risk of getting cancer.
Alachlor (ppb).002100020Runoff from herbicide used on row cropsSome people who drink water containing alachlor in excess of the MCL over many years could have problems with their eyes, liver, kidneys, or spleen, or experience anemia, and may have an increased risk of getting cancer.
Atrazine (ppb).003100033Runoff from herbicide used on row cropsSome people who drink water containing atrazine well in excess of the MCL over many years could experience problems with their cardiovascular system or reproductive difficulties.
Benzo(a)pyrene [PAH] (nanograms/l).00021,000,0002000Leaching from linings of water storage tanks and distribution linesSome people who drink water containing benzo(a)pyrene in excess of the MCL over many years may experience reproductive difficulties and may have an increased risk of getting cancer.
Carbofuran (ppb).0410004040Leaching of soil fumigant used on rice and alfalfaSome people who drink water containing carbofuran in excess of the MCL over many years could experience problems with their blood, or nervous or reproductive systems.
Chlordane (ppb).002100020Residue of banned termiticideSome people who drink water containing chlordane in excess of the MCL over many years could experience problems with their liver or nervous system, and may have an increased risk of getting cancer.
Dalapon (ppb).21000200200Runoff from herbicide used on rights of waySome people who drink water containing dalapon well in excess of the MCL over many years could experience minor kidney changes.
Di(2-ethylhexyl) adipate (ppb).41000400400Discharge from chemical factoriesSome people who drink water containing di(2-ethylhexyl) adipate well in excess of the MCL over many years could experience toxic effects such as weight loss, liver enlargement or possible reproductive difficulties.
Di(2-ethylhexyl) phthalate (ppb).006100060Discharge from rubber and chemical factoriesSome people who drink water containing di(2-ethylhexyl) phthalate well in excess of the MCL over many years may have problems with their liver, or experience reproductive difficulties, and may have an increased risk of getting cancer.
Dibromochloropropane (ppt).00021,000,0002000Runoff/leaching from soil fumigant used on soybeans, cotton, pineapples, and orchardsSome people who drink water containing DBCP in excess of the MCL over many years could experience reproductive problems and may have an increased risk of getting cancer.
Dinoseb (ppb).007100077Runoff from herbicide used on soybeans and vegetablesSome people who drink water containing dinoseb well in excess of the MCL over many years could experience reproductive difficulties.
Diquat (ppb).0210002020Runoff from herbicide useSome people who drink water containing diquat in excess of the MCL over many years could get cataracts.
Dioxin [2,3,7,8-TCDD] (ppq).000000031,000,000, 000300Emissions from waste incineration and other combustion; Discharge from chemical factoriesSome people who drink water containing dioxin in excess of the MCL over many years could experience reproductive difficulties and may have an increased risk of getting cancer.
Endothall (ppb).11000100100Runoff from herbicide useSome people who drink water containing endothall in excess of the MCL over many years could experience problems with their stomach or intestines.
Endrin (ppb).002100022Residue of banned insecticideSome people who drink water containing endrin in excess of the MCL over many years could experience liver problems.
EpichlorohydrinTTTT0Discharge from industrial chemical factories; An impurity of some water treatment chemicalsSome people who drink water containing high levels of epichlorohydrin over a long period of time could experience stomach problems, and may have an increased risk of getting cancer.
Ethylene dibromide (ppt).000051,000,000500Discharge from petroleum refineriesSome people who drink water containing ethylene dibromide in excess of the MCL over many years could experience problems with their liver, stomach, reproductive system, or kidneys, and may have an increased risk of getting cancer.
Glyphosate (ppb).71000700700Runoff from herbicide useSome people who drink water containing glyphosate in excess of the MCL over many years could experience problems with their kidneys or reproductive difficulties.
Heptachlor (ppt).00041,000,0004000Residue of banned pesticideSome people who drink water containing heptachlor in excess of the MCL over many years could experience liver damage and may have an increased risk of getting cancer.
Heptachlor epoxide (ppt).00021,000,0002000Breakdown of heptachlorSome people who drink water containing heptachlor epoxide in excess of the MCL over many years could experience liver damage, and may have an increased risk of getting cancer.
Hexachlorobenzene (ppb).001100010Discharge from metal refineries and agricultural chemical factoriesSome people who drink water containing hexachlorobenzene in excess of the MCL over many years could experience problems with their liver or kidneys, or adverse reproductive effects, and may have an increased risk of getting cancer.
Hexachlorocyclopentadiene (ppb).0510005050Discharge from chemical factoriesSome people who drink water containing hexachlorocyclopentadiene well in excess of the MCL over many years could experience problems with their kidneys or stomach.
Lindane (ppt).00021,000,000200200Runoff/leaching from insecticide used on cattle, lumber, gardensSome people who drink water containing lindane in excess of the MCL over many years could experience problems with their kidneys or liver.
Methoxychlor (ppb).0410004040Runoff/leaching from insecticide used on fruits, vegetables, alfalfa, livestockSome people who drink water containing methoxychlor in excess of the MCL over many years could experience reproductive difficulties.
Oxamyl [Vydate] (ppb).21000200200Runoff/leaching from insecticide used on apples, potatoes and tomatoesSome people who drink water containing oxamyl in excess of the MCL over many years could experience slight nervous system effects.
PCBs [Polychlorinated biphenyls] (ppt).00051,000,0005000Runoff from landfills; Discharge of waste chemicalsSome people who drink water containing PCBs in excess of the MCL over many years could experience changes in their skin, problems with their thymus gland, immune deficiencies, or reproductive or nervous system difficulties, and may have an increased risk of getting cancer.
Pentachlorophenol (ppb).001100010Discharge from wood preserving factoriesSome people who drink water containing pentachlorophenol in excess of the MCL over many years could experience problems with their liver or kidneys, and may have an increased risk of getting cancer.
Picloram (ppb).51000500500Herbicide runoffSome people who drink water containing picloram in excess of the MCL over many years could experience problems with their liver.
Simazine (ppb).004100044Herbicide runoffSome people who drink water containing simazine in excess of the MCL over many years could experience problems with their blood.
Toxaphene (ppb).003100030Runoff/leaching from insecticide used on cotton and cattleSome people who drink water containing toxaphene in excess of the MCL over many years could have problems with their kidneys, liver, or thyroid, and may have an increased risk of getting cancer.
Volatile organic contaminants:
Benzene (ppb).005100050Discharge from factories; Leaching from gas storage tanks and landfillsSome people who drink water containing benzene in excess of the MCL over many years could experience anemia or a decrease in blood platelets, and may have an increased risk of getting cancer.
Carbon tetrachloride (ppb).005100050Discharge from chemical plants and other industrial activitiesSome people who drink water containing carbon tetrachloride in excess of the MCL over many years could experience problems with their liver and may have an increased risk of getting cancer.
Chlorobenzene (ppb).11000100100Discharge from chemical and agricultural chemical factoriesSome people who drink water containing chlorobenzene in excess of the MCL over many years could experience problems with their liver or kidneys.
o-Dichlorobenzene (ppb).61000600600Discharge from industrial chemical factoriesSome people who drink water containing o-dichlorobenzene well in excess of the MCL over many years could experience problems with their liver, kidneys, or circulatory systems.
p-Dichlorobenzene (ppb).07510007575Discharge from industrial chemical factoriesSome people who drink water containing p-dichlorobenzene in excess of the MCL over many years could experience anemia, damage to their liver, kidneys, or spleen, or changes in their blood.
1,2-Dichloroethane (ppb).005100050Discharge from industrial chemical factoriesSome people who drink water containing 1,2-dichloroethane in excess of the MCL over many years may have an increased risk of getting cancer.
1,1-Dichloroethylene (ppb).007100077Discharge from industrial chemical factoriesSome people who drink water containing 1,1-dichloroethylene in excess of the MCL over many years could experience problems with their liver.
cis-1,2-Dichloroethylene (ppb).0710007070Discharge from industrial chemical factoriesSome people who drink water containing cis-1,2-dichloroethylene in excess of the MCL over many years could experience problems with their liver.
trans-1,2-Dichloroethylene (ppb).11000100100Discharge from industrial chemical factoriesSome people who drink water containing trans-1,2-dichloroethylene well in excess of the MCL over many years could experience problems with their liver.
Dichloromethane (ppb).005100050Discharge from pharmaceutical and chemical factoriesSome people who drink water containing dichloromethane in excess of the MCL over many years could have liver problems and may have an increased risk of getting cancer.
1,2-Dichloropropane (ppb).005100050Discharge from industrial chemical factoriesSome people who drink water containing 1,2-dichloropropane in excess of the MCL over many years may have an increased risk of getting cancer.
Ethylbenzene (ppb).71000700700Discharge from petroleum refineriesSome people who drink water containing ethylbenzene well in excess of the MCL over many years could experience problems with their liver or kidneys.
Haloacetic Acids (HAA) (ppb).060100060N/ABy-product of drinking water disinfectionSome people who drink water containing haloacetic acids in excess of the MCL over many years may have an increased risk of getting cancer.
Styrene (ppb).11000100100Discharge from rubber and plastic factories; Leaching from landfillsSome people who drink water containing styrene well in excess of the MCL over many years could have problems with their liver, kidneys, or circulatory system.
Tetrachloroethylene (ppb).005100050Discharge from factories and dry cleanersSome people who drink water containing tetrachloroethylene in excess of the MCL over many years could have problems with their liver, and may have an increased risk of getting cancer.
1,2,4-Trichlorobenzene (ppb).0710007070Discharge from textile-finishing factoriesSome people who drink water containing 1,2,4-trichlorobenzene well in excess of the MCL over many years could experience changes in their adrenal glands.
1,1,1-Trichloroethane (ppb).21000200200Discharge from metal degreasing sites and other factoriesSome people who drink water containing 1,1,1-trichloroethane in excess of the MCL over many years could experience problems with their liver, nervous system, or circulatory system.
1,1,2-Trichloroethane (ppb).005100053Discharge from industrial chemical factoriesSome people who drink water containing 1,1,2-trichloroethane well in excess of the MCL over many years could have problems with their liver, kidneys, or immune systems.
Trichloroethylene (ppb).005100050Discharge from metal degreasing sites and other factoriesSome people who drink water containing trichloroethylene in excess of the MCL over many years could experience problems with their liver and may have an increased risk of getting cancer.
TTHMs [Total trihalomethanes] (ppb)0.10/.0801000100/80N/ABy-product of drinking water disinfectionSome people who drink water containing trihalomethanes in excess of the MCL over many years may experience problems with their liver, kidneys, or central nervous systems, and may have an increased risk of getting cancer.
Toluene (ppm)111Discharge from petroleum factoriesSome people who drink water containing toluene well in excess of the MCL over many years could have problems with their nervous system, kidneys, or liver.
Vinyl Chloride (ppb).002100020Leaching from PVC piping; Discharge from plastics factoriesSome people who drink water containing vinyl chloride in excess of the MCL over many years may have an increased risk of getting cancer.
Xylenes (ppm)101010Discharge from petroleum factories; Discharge from chemical factoriesSome people who drink water containing xylenes in excess of the MCL over many years could experience damage to their nervous system.

†Until March 31, 2016.

‡Beginning April 1, 2016.

1These arsenic values are effective January 23, 2006. Until then, the MCL is 0.05 mg/L and there is no MCLG.

Key:

AL = Action Level

MCL = Maximum Contaminant Level

MCLG = Maximum Contaminant Level Goal

MFL = million fibers per liter

MRDL = Maximum Residual Disinfectant Level

MRDLG = Maximum Residual Disinfectant Level Goal

mrem/year = millirems per year (a measure of radiation absorbed by the body)

N/A = Not Applicable

NTU = Nephelometric Turbidity Units (a measure of water clarity)

pCi/l = picocuries per liter (a measure of radioactivity)

ppm = parts per million, or milligrams per liter (mg/l)

ppb = parts per billion, or micrograms per liter (µg/l)

ppt = parts per trillion, or nanograms per liter

ppq = parts per quadrillion, or picograms per liter

TT = Treatment Technique

[65 FR 26024, May 4, 2000, as amended at 65 FR 76749, Dec. 7, 2000; 66 FR 7064, Jan. 22, 2001; 67 FR 70855, Nov. 27, 2002; 67 FR 73011, Dec. 9, 2002; 68 FR 14506, Mar. 25, 2003; 71 FR 65652, Nov. 8, 2006; 78 FR 10349, Feb. 13, 2013]

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