Drinking water contaminants, A–Z
The 97 contaminants U.S. public water utilities report in their annual Consumer Confidence Report, grouped into 9 families. Each one links to every public water system that measures it, ranked against the federal limit — the measured value transcribed from each utility's own report.
Metals21
AluminumA common element sometimes used as a treatment coagulant.ArsenicA naturally occurring element that also enters water from industry and agriculture.BariumA metal from erosion of natural deposits and industrial discharge.BoronA naturally occurring element from rock and soil.CalciumA naturally occurring mineral that contributes to water hardness.Chromium, HexavalentHexavalent chromium ('chromium-6') — the more toxic form of chromium.Chromium, TotalTotal chromium — the sum of all chromium forms, from natural deposits and industrial discharge.CopperA metal that enters water from corroding household plumbing.GermaniumA trace metalloid found in some source water.IronA naturally occurring metal common in groundwater.LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures.LithiumA naturally occurring element found in some groundwater.MagnesiumA naturally occurring mineral that contributes to water hardness.ManganeseA naturally occurring metal from soil and rock.MercuryA toxic metal from erosion of natural deposits and industrial runoff.NickelA metal from natural deposits and industrial discharge.PotassiumA naturally occurring mineral from rock and soil.SeleniumA trace element from natural deposits and industrial discharge.SilicaA naturally occurring compound from sand and rock.SodiumA naturally occurring salt component.ZincA naturally occurring metal that can also enter water from corroding pipes.
PFAS ("forever chemicals")29
11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid, a chlorinated PFAS compound.4,8-Dioxa-3H-perfluorononanoic acid (ADONA)ADONA, a newer-generation PFAS replacement compound.4:2 Fluorotelomer sulfonic acid (4:2 FTS)4:2 fluorotelomer sulfonic acid, a PFAS-related compound.6:2 Fluorotelomer sulfonic acid (6:2 FTS)6:2 fluorotelomer sulfonic acid, a PFAS-related compound.8:2 Fluorotelomer sulfonic acid (8:2 FTS)8:2 fluorotelomer sulfonic acid, a PFAS-related compound.9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (9Cl-PF3ONS)9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid, a chlorinated PFAS compound.Hexafluoropropylene oxide dimer acidHFPO-DA ('GenX chemicals'), a newer-generation PFAS replacement compound.N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)N-ethyl perfluorooctanesulfonamidoacetic acid, a PFAS-related compound.N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)N-methyl perfluorooctanesulfonamidoacetic acid, a PFAS-related compound.Nonafluoro-3,6-dioxaheptanoic acidNonafluoro-3,6-dioxaheptanoic acid, a PFAS-related compound.Perfluoro-3-methoxypropanoic acid (PFMPA)Perfluoro-3-methoxypropanoic acid, a PFAS-related compound.Perfluoro-4-methoxybutanoic acid (PFMBA)Perfluoro-4-methoxybutanoic acid, a PFAS-related compound.Perfluoro(2-ethoxyethane)sulfonic acid (PFEESA)Perfluoro(2-ethoxyethane)sulfonic acid, a PFAS-related compound.Perfluorobutanesulfonic acidPerfluorobutanesulfonic acid, a shorter-chain PFAS 'forever chemical.'Perfluorodecanoic acid (PFDA)Perfluorodecanoic acid, a longer-chain PFAS 'forever chemical.'Perfluorododecanoic acid (PFDoA)Perfluorododecanoic acid, a longer-chain PFAS 'forever chemical.'Perfluoroheptanesulfonic acid (PFHpS)Perfluoroheptanesulfonic acid, a PFAS 'forever chemical.'Perfluoroheptanoic acidPerfluoroheptanoic acid, a PFAS 'forever chemical.'Perfluorohexanesulfonic acidPerfluorohexanesulfonic acid, a PFAS 'forever chemical.'Perfluorohexanoic acidPerfluorohexanoic acid, a shorter-chain PFAS 'forever chemical.'Perfluorononanoic acidPerfluorononanoic acid, a PFAS 'forever chemical.'Perfluoropentanesulfonic acid (PFPeS)Perfluoropentanesulfonic acid, a PFAS 'forever chemical.'Perfluoropentanoic acidPerfluoropentanoic acid, a shorter-chain PFAS 'forever chemical.'Perfluorotetradecanoic acid (PFTeDA)Perfluorotetradecanoic acid, a longer-chain PFAS 'forever chemical.'Perfluorotridecanoic acid (PFTrDA)Perfluorotridecanoic acid, a longer-chain PFAS 'forever chemical.'Perfluoroundecanoic acid (PFUnA)Perfluoroundecanoic acid, a longer-chain PFAS 'forever chemical.'PFBAPerfluorobutanoic acid, a shorter-chain PFAS 'forever chemical.'PFOAPerfluorooctanoic acid, a PFAS 'forever chemical' once used in nonstick and stain-resistant products.PFOSPerfluorooctanesulfonic acid, a PFAS 'forever chemical' once used in firefighting foam and coatings.
Disinfection byproducts10
BromateA disinfection byproduct formed when bromide-containing water is treated with ozone.Bromodichloroacetic acidA brominated haloacetic acid disinfection byproduct.BromodichloromethaneA trihalomethane disinfection byproduct.BromoformA trihalomethane disinfection byproduct.ChlorateA byproduct that can form during disinfection, especially when hypochlorite solutions degrade.ChloroformA trihalomethane formed when chlorine reacts with organic matter in water.DibromochloromethaneA trihalomethane disinfection byproduct.HAA5Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter.PerchlorateA chemical used in rocket fuel and fireworks that can also form during disinfection.TTHMTotal trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter.
Inorganic chemicals12
BromideA naturally occurring salt found in source water.Bromochloroacetic acidA mixed-halogen haloacetic acid disinfection byproduct.ChlorideA naturally occurring salt compound.Chlorodibromoacetic acidA brominated haloacetic acid disinfection byproduct.Dibromoacetic acidA brominated haloacetic acid disinfection byproduct.Dichloroacetic acidA haloacetic acid disinfection byproduct.FluorideA mineral often added to drinking water to help prevent tooth decay.Monobromoacetic acidA brominated haloacetic acid disinfection byproduct.NitrateA compound from fertilizer runoff, septic systems, and erosion of natural deposits.NitriteA compound from fertilizer runoff, sewage, and erosion of natural deposits.SulfateA naturally occurring mineral from rock and soil.Trichloroacetic acidA haloacetic acid disinfection byproduct.
Radionuclides5
Combined RadiumCombined radium-226 and radium-228 — naturally occurring radioactive elements.Gross AlphaGross alpha particle activity — a combined measure of alpha-emitting radioactive substances.Gross Beta Particle ActivityGross beta particle activity — a combined measure of beta-emitting radioactive substances.RadonA naturally occurring radioactive gas that can dissolve into groundwater.UraniumA naturally occurring radioactive metal from erosion of natural deposits.
Microbial2
VOCs & pesticides6
AtrazineA widely used agricultural herbicide that reaches water through runoff.ChloroethaneA volatile organic compound used in some industrial processes.DBCP1,2-dibromo-3-chloropropane — a banned soil fumigant pesticide.TetrachloroethyleneAn industrial solvent (PCE) used in dry cleaning and degreasing.TrichloroethyleneAn industrial solvent (TCE) used in metal degreasing.XylenesA group of industrial solvents found in gasoline and paint.
Disinfectants2
Physical & aggregate10
AlkalinityA measure of the water's capacity to neutralize acids.ColorA measure of visible tint in the water.HardnessA measure of dissolved calcium and magnesium minerals.OdorA measure of detectable smell in the water.pHA measure of how acidic or basic the water is.Specific ConductanceA measure of how well water conducts electricity, which tracks dissolved mineral content.TemperatureThe measured temperature of the water sample.TOCTotal organic carbon — a measure of organic material dissolved in the water.Total Dissolved SolidsTotal dissolved solids — the combined content of all dissolved minerals and salts.TurbidityA measure of cloudiness from suspended particles in the water.
Dataset
The full water-quality dataset →
How it's built, what it covers, and the free JSON + Markdown API.
By place
Browse water systems by state →
Every U.S. public water system, with its full contaminant report.