Resources for Households

EPA Standards for Drinking Water Contaminants

ContaminantSymbolEPA Maximum Contaminant Level*Standard TypeCommon Sources of Contaminant in Drinking Water
AntimonySb6 ppbPrimaryDischarge from various industries
ArsenicAs10 ppbPrimaryErosion of natural deposits and runoff from orchards
BariumBa2000 ppbPrimaryErosion of natural deposits and industrial discharge
BerylliumBe4 ppbPrimaryDischarge from various industries
CadmiumCd5 ppbPrimaryErosion of natural deposits, industrial discharge, and erosion of galvanized pipes
ChromiumCr100 ppbPrimaryErosion of natural deposits and industrial discharge
CopperCu1300 ppbSecondaryErosion of natural deposits and corrosion of household plumbing systems
IronFe300 ppbSecondaryErosion of natural deposits
LeadPb15 ppbPrimaryErosion of natural deposits and corrosion of household plumbing systems
ManganeseMn50 ppbSecondaryErosion of natural deposits and industrial discharge
NickelNiDoes not have maximum contaminant level setN/AErosion of natural deposits and industrial discharge
SeleniumSe50 ppbPrimaryErosion of natural deposits and industrial discharge
ThalliumTl2 ppbPrimaryIndustrial discharge
UraniumU30 ppbPrimaryErosion of natural deposits
*National Primary Drinking Water Regulations (NPDWRs), primary standards, are legally enforceable standards that apply to public water systems. National Secondary Drinking Water Regulations (NSDWRs), secondary standards, are non-enforceable guidelines regulating contaminants that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, color) in drinking water.

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