Groundwater Quality Standards

The following numerical and narrative standards apply to all groundwater of the state and shall not be exceeded unless otherwise allowed in this rule. (7-1-26) 01. Numerical Groundwater Quality Standards. (7-1-26) a. The Primary Constituent Standards are based on protection of human health and are identified in Table II. Table II - Primary Constituent Standards Chemical Abstract Service Number Constituent Standard (mg/l unless otherwise specified) 7440-36-0 Antimony 0.006 7440-38-2 Arsenic 0.05 1332-21-4 Asbestos 7 million fibers/l longer than 10 um 7440-39-3 Barium 2 7440-41-7 Beryllium 0.004 7440-43-9 Cadmium 0.005 7440-47-3 Chromium 0.1 7440-50-8 Copper 1.3 Table Footnotes *1 No Chemical Abstract Service Number exists for this constituent. 2 An exceedance of the primary ground water quality standard for total coliform is not a violation of these rules. If the primary ground water quality standard for total coliform is exceeded, additional analysis for fecal coliform or E. coli will be conducted. An exceedance of the primary ground water quality standards for either fecal coli- form or E. coli is a violation of these rules. IDAHO ADMINISTRATIVE CODE IDAPA 58.01.11 Department of Environmental Quality Groundwater Quality Rule Section 200.01 Page 7 57-12-5 Cyanide 0.2 16984-48-8 Fluoride 4 7439-92-1 Lead 0.015 7439-97-6 Mercury 0.002 *1 Nitrate (as N) 10 *1 Nitrite (as N) 1 *1 Nitrate and Nitrite (both as N) 10 7782-49-2 Selenium 0.05 7440-28-0 Thallium 0.002 15972-60-8 Alachlor 0.002 1912-24-9 Atrazine 0.003 71-43-2 Benzene 0.005 50-32-8 Benzo(a)pyrene (PAH) 0.0002 75-27-4 Bromodichloromethane (THM) 0.1 75-25-2 Bromoform (THM) 0.1 1563-66-2 Carbofuran 0.04 56-23-5 Carbon Tetrachloride 0.005 57-74-9 Chlordane 0.002 124-48-1 Chlorodibromomethane (THM) 0.1 67-66-3 Chloroform(THM) 0.002 94-75-7 2,4-D 0.07 75-99-0 Dalapon 0.2 103-23-1 Di(2-ethylhexyl) adipate 0.4 96-12-8 Dibromochloropropane 0.0002 541-73-1 Dichlorobenzene m- 0.6 95-50-1 Dichlorobenzene o- 0.6 106-46-7 1,4(para)-Dichlorobenzene or Dichlorobenzene p- 0.075 Table II - Primary Constituent Standards Chemical Abstract Service Number Constituent Standard (mg/l unless otherwise specified) Table Footnotes *1 No Chemical Abstract Service Number exists for this constituent. 2 An exceedance of the primary ground water quality standard for total coliform is not a violation of these rules. If the primary ground water quality standard for total coliform is exceeded, additional analysis for fecal coliform or E. coli will be conducted. An exceedance of the primary ground water quality standards for either fecal coli- form or E. coli is a violation of these rules. IDAHO ADMINISTRATIVE CODE IDAPA 58.01.11 Department of Environmental Quality Groundwater Quality Rule Section 200.01 Page 8 107-06-2 1,2-Dichloroethane 0.005 75-35-4 1,1-Dichloroethylene 0.007 156-59-2 cis-1, 2-Dichloroethylene 0.07 156-60-5 trans-1, 2-Dichloroethylene 0.1 75-09-2 Dichloromethane 0.005 78-87-5 1,2-Dichloropropane 0.005 117-81-7 Di(2-ethylhexyl)phthalate 0.006 88-85-7 Dinoseb 0.007 85-00-7 Diquat 0.02 145-73-3 Endothall 0.1 72-20-8 Endrin 0.002 100-41-4 Ethylbenzene 0.7 106-93-4 Ethylene dibromide 0.00005 1071-83-6 Glyphosate 0.7 76-44-8 Heptachlor 0.0004 1024-57-3 Heptachlor epoxide 0.0002 118-74-1 Hexachlorobenzene 0.001 77-47-4 Hexachlorocyclopentadiene 0.05 58-89-9 Lindane 0.0002 72-43-5 Methoxychlor 0.04 108-90-7 Monochlorobenzene 0.1 23135-22-0 Oxamyl (Vydate) 0.2 87-86-5 Pentachlorophenol 0.001 1918-02-1 Picloram 0.5 1336-36-3 Polychlorinated biphenyls (PCBs) 0.0005 122-34-9 Simazine 0.004 100-42-5 Styrene 0.1 Table II - Primary Constituent Standards Chemical Abstract Service Number Constituent Standard (mg/l unless otherwise specified) Table Footnotes *1 No Chemical Abstract Service Number exists for this constituent. 2 An exceedance of the primary ground water quality standard for total coliform is not a violation of these rules. If the primary ground water quality standard for total coliform is exceeded, additional analysis for fecal coliform or E. coli will be conducted. An exceedance of the primary ground water quality standards for either fecal coli- form or E. coli is a violation of these rules. IDAHO ADMINISTRATIVE CODE IDAPA 58.01.11 Department of Environmental Quality Groundwater Quality Rule Section 200.01 Page 9 (3-24-22) 1746-01-6 2,3,7,8-TCDD (Dioxin) 3.0 x 10-8 127-18-4 Tetrachloroethylene 0.005 108-88-3 Toluene 1 *1 Total Trihalomethanes [the sum of the concentrations of bromodichloromethane, dibromochloromethane, tribromomethane (bromoform), and trichloromethane (chloroform)] 0.1 8001-35-2 Toxaphene 0.003 93-72-1 2,4,5-TP (Silvex) 0.05 120-82-1 1,2,4-Trichlorobenzene 0.07 71-55-6 1,1,1-Trichloroethane 0.2 79-00-5 1,1,2-Trichloroethane 0.005 79-01-6 Trichloroethylene 0.005 75-01-4 Vinyl Chloride 0.002 1330-20-7 Xylenes (total) 10 *1 Gross alpha particle activity (including radium -226, but excluding radon and uranium) 15 pCi/l *1 Combined beta/photon emitters 4 millirems/year effective dose equivalent *1 Combined Radium - 226 and radium 228 5 pCi/l *1 Strontium 90 8 pCi/l *1 Tritium 20,000 pCi/l *1 Total Coliform2 1 colony forming unit/100 ml Escherichia coliform (E. coli) Less than 1 viable colony or col- ony forming unit/100 ml using any EPA approved method Fecal coliform Less than 1 viable colony or col- ony forming unit/100 ml using any EPA approved method Table II - Primary Constituent Standards Chemical Abstract Service Number Constituent Standard (mg/l unless otherwise specified) Table Footnotes *1 No Chemical Abstract Service Number exists for this constituent. 2 An exceedance of the primary ground water quality standard for total coliform is not a violation of these rules. If the primary ground water quality standard for total coliform is exceeded, additional analysis for fecal coliform or E. coli will be conducted. An exceedance of the primary ground water quality standards for either fecal coli- form or E. coli is a violation of these rules. IDAHO ADMINISTRATIVE CODE IDAPA 58.01.11 Department of Environmental Quality Groundwater Quality Rule Section 200.01 Page 10 b. The Secondary Constituent Standards are generally based on aesthetic qualities and are identified in Table III. (7-1-26) c. Sample preservation and analytical procedures to determine compliance with the standards identified in Subsection 200.01 must be in accordance with Subsections 200.01.c.i. and ii., except that cyanide must be analyzed as weak acid dissociable cyanide, as defined in IDAPA 58.01.13, “Rules for Ore Processing by Cyanidation,” or other methods approved by the Department: (7-1-26) i. 40 CFR Part 141, National Primary Drinking Water Regulations, Subpart C, Monitoring and Analytical Requirements, provided in IDAPA 58.01.08, “Idaho Rules for Public Drinking Water Systems”; or (7-1-26) ii. Another method approved by the Department. (3-24-22) 02. Narrative Groundwater Quality Standards. Contaminant concentrations, alone or in combination with other contaminants or properties, may not cause the groundwater to be hazardous, deleterious, carcinogenic, mutagenic, teratogenic, or toxic. Determinations of specific numerical levels when applying this standard must be based on: (7-1-26) a. Best scientific information currently available on adverse effects of the contaminant(s); (3-24-22) b. Protection of a beneficial use; or (3-24-22) c. Practical quantitation levels for the contaminant(s), if they exceed the levels identified in Subsection 200.02.a. or 200.02.b. (3-24-22) Table III. Secondary Constituent Standards Constituent Standard (mg/l unless otherwise specified) Aluminum 0.2 Chloride 250 Color 15 Color Units Foaming Agents 0.5 Iron 0.3 Manganese 0.05 Odor 3.0 Threshold Odor Num- ber pH 6.5 to 8.5 (no units apply) Silver 0.1 Sulfate 250 Total Dissolved Solids 500 Zinc 5 IDAHO ADMINISTRATIVE CODE IDAPA 58.01.11 Department of Environmental Quality Groundwater Quality Rule Section 300 Page 11 03. Natural Background Level. If the natural background level of a constituent exceeds the standard in this section, the natural background level will be used as the standard. (7-1-26) 201. -- 299. (RESERVED)