Statutes, codes, and regulations
Idaho Administrative Code
Title IDAPA 58 - Environmental Quality, Department of
Rule 58.01.11 - GROUND WATER QUALITY RULE
Section 58.01.11.200 - GROUND WATER QUALITY STANDARDS

Idaho Admin. Code r. 58.01.11.200

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Current through September 2, 2024
Section 58.01.11.200 - GROUND WATER QUALITY STANDARDS

The following numerical and narrative standards apply to all ground water of the state and shall not be exceeded unless otherwise allowed in this rule.

01.Numerical Ground Water Quality Standards.
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

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

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

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 colony forming unit/100 ml using any EPA approved method

Fecal coliform

Less than 1 viable colony or colony forming unit/100 ml using any EPA approved method

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 coliform or E. coli is a violation of these rules.

b. The Secondary Constituent Standards are generally based on aesthetic qualities and are identified in Table III.

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 Number

PH

6.5 to 8.5 (no units apply)

Silver

0.1

Sulfate

250

Total Dissolved Solids

500

Zinc

5

c. Sample preservation and analytical procedures to determine compliance with the standards identified in Subsection 200.01 shall be in accordance with the following, except that cyanide shall be analyzed as weak acid dissociable cyanide using a method approved by the Department:
i. Environmental Protection Agency, Code of Federal Regulations, Title 40, Parts 141 and 143, revised as of July 2001; or
ii. Another method approved by the Department.
02.Narrative Ground Water Quality Standards. Contaminant concentrations, alone or in combination with other contaminants or properties, shall not cause the ground water to be hazardous, deleterious, carcinogenic, mutagenic, teratogenic, or toxic. Determinations of specific numerical levels when applying this standard shall be based on:
a. Best scientific information currently available on adverse effects of the contaminant(s);
b. Protection of a beneficial use; or
c. Practical quantitation levels for the contaminant(s), if they exceed the levels identified in Subsection 200.02.a. or 200.02.b.
03.Natural Background Level. If the natural background level of a constituent exceeds the standard in this section, the natural background level shall be used as the standard.

Idaho Admin. Code r. 58.01.11.200

Effective March 24, 2022