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This website publishes administrative rules on their effective dates, as designated by the adopting state agencies, colleges, and universities.

Rule 3745-81-12 | Maximum contaminant levels and best available technologies for organic contaminants.

 

(A) The director may determine that a public water system shall apply the following best available technology (BAT), for achieving compliance with the maximum contaminant levels (MCLs) for organic disinfection byproducts identified in this table:

ContaminantMCL (mg/L)BAT
Total trihalomethanes 0.080Enhanced coagulation or enhanced softening plus GAC10; ornanofiltration with a molecular weight of less than or equal to 1000 Daltons;or GAC20
Haloacetic acids(five)0.060Enhanced coagulation or enhanced softening plusGAC10; or nanofiltration with a molecular weight of less than or equal to 1000Daltons; or GAC20

(B) The director may determine that a public water system shall apply the following best technology, treatment techniques or other means available for achieving compliance with the MCLs for TTHM and HAA5 identified in this rule for consecutive systems and applies only to the disinfected water that consecutive systems buy or otherwise receive:

ContaminantMCL(mg/L)BAT
Total trihalomethanes0.080Systems servinggreater than or equal to 10,000: Improved distribution system and storage tankmanagement to reduce residence time, plus the use of chloramines fordisinfectant residual maintenance. Systems serving less than 10,000: Improveddistribution system and storage tank management to reduce residencetime.
Haloacetic acids(five)0.060Systems serving greater than or equal to 10,000:Improved distribution system and storage tank management to reduce residencetime, plus the use of chloramines for disinfectant residual maintenance.Systems serving less than 10,000: Improved distribution system and storage tankmanagement to reduce residence time.

(C) The following maximum contaminant levels (MCLs) apply to community public water systems and nontransient noncommunity public water systems. The associated BATs, designated as GAC for granular activated carbon and PTA for packed-tower aeration, identify the best technology, treatment techniques or other means available for achieving compliance with the stated MCLs. The director may determine that a public water system shall apply best available technology in order to reduce the level of a contaminant to below its MCL.

ContaminantCASnumberMCL (mg/L) BAT
Vinyl chloride75-01-40.002PTA
Benzene71-43-20.005 GAC PTA
Carbon tetrachloride 56-23-5 0.005GACPTA
p-Dichlorobenzene106-46-7 0.075 GAC PTA
1,2-Dichloroethane 107-06-20.005GACPTA
1,1-Dichloroethylene75-35-4 0.007GAC PTA
Trichloroethylene79-01-60.005GAC PTA
1,1,1-Trichloroethane 71-55-6 0.2 GACPTA
o-Dichlorobenzene95-50-10.6GAC PTA
cis-1,2-Dichloroethylene 156-59-20.07GACPTA
trans-1,2-Dichloroethylene156-60-50.1 GACPTA
1,2-Dichloropropane78-87-5 0.005GAC PTA
Dichloromethane 75-09-20.005PTA
Ethylbenzene 100-41-40.7GAC PTA
Monochlorobenzene 108-90-70.1GACPTA
Styrene100-42-50.1GACPTA
Tetrachloroethylene127-18-40.005GAC PTA
Toluene108-88-31GACPTA
1,2,4-Trichlorobenzene120-82-10.07GAC PTA
1,1,2-Trichloroethane 79-00-50.005 GACPTA
Xylenes(total)1330-20-710GACPTA

(D) The following maximum contaminant levels apply to community public water systems and nontransient noncommunity water systems. The associated BATs, designated as GAC for granular activated carbon, PTA for packed-tower aeration, and OX for oxidation with chlorine or ozone, identify the best technology, treatment technique or other means available for achieving compliance with the stated MCLs. The director may determine that a public water system shall apply BAT in order to reduce the level of a contaminant to below its MCL.

Contaminant CASnumberMCL (mg/L)BAT
Alachlor 15972-60-80.002GAC
Atrazine 1912-24-90.003GAC
Benzo[a]pyrene 50-32-80.0002GAC
Carbofuran 1563-66-20.04GAC
Chlordane 57-74-90.002GAC
2,4-D94-75-70.07GAC
Dalapon75-99-00.2GAC
Dibromochloropropane (DBCP) 96-12-80.0002GACPTA
Di(2-ethylhexyl)adipate 103-23-10.4 GAC
Di(2-ethylhexyl) phthalate 117-81-70.006GAC
Dinoseb88-85-70.007GAC
Diquat85-00-70.02GAC
Endothall 145-73-30.1GAC
Endrin72-20-80.002GAC
Ethylene dibromide (EDB)106-93-40.00005GACPTA
Glyphosate1071-53-60.7 OX
Heptachlor 76-44-80.0004 GAC
Heptachlor epoxide1024-57-30.0002GAC
Hexachlorobenzene 118-74-10.001GAC
Hexachlorocyclopentadiene 77-47-4 0.05GACPTA
Lindane58-89-90.0002 GAC
Methoxychlor 72-43-50.04GAC
Oxamyl(Vydate) 23135-22-00.2GAC
Picloram 1918-02-10.5GAC
Polychlorinated biphenyls (PCBs) 1336-36-30.0005GAC
Pentachlorophenol 87-86-50.001GAC
Simazine 122-34-90.004GAC
2,3,7,8-TCDD (Dioxin) 1745-01-63 x10-8GAC
Toxaphene8001-35-20.003GAC
2,4,5-TP (Silvex) 93-72-10.05GAC

Last updated October 26, 2022 at 2:00 PM

Supplemental Information

Authorized By: 6109.04
Amplifies: 6109.03, 6109.04
Five Year Review Date: 3/27/2022
Prior Effective Dates: 12/27/1978, 8/24/1981, 5/22/1989, 9/13/1993, 1/1/2002, 1/1/2010