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:
| Contaminant | MCL (mg/L) | BAT |
| Total trihalomethanes | 0.080 | Enhanced coagulation or enhanced softening plus GAC10; or nanofiltration with a molecular weight of less than or equal to 1000 Daltons; or GAC20 |
| Haloacetic acids(five) | 0.060 | Enhanced coagulation or enhanced softening plus GAC10; or nanofiltration with a molecular weight of less than or equal to 1000 Daltons; 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:
| Contaminant | MCL(mg/L) | BAT |
| Total trihalomethanes | 0.080 | Systems serving greater than or equal to 10,000: Improved distribution system and storage tank management to reduce residence time, plus the use of chloramines for disinfectant residual maintenance. Systems serving less than 10,000: Improved distribution system and storage tank management to reduce residence time. |
| Haloacetic acids(five) | 0.060 | Systems serving greater than or equal to 10,000: Improved distribution system and storage tank management to reduce residence time, plus the use of chloramines for disinfectant residual maintenance. Systems serving less than 10,000: Improved distribution system and storage tank management 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 the contaminant's MCL.
| Contaminant | CAS number | MCL (mg/L) | BAT |
| Vinyl chloride | 75-01-4 | 0.002 | PTA |
| Benzene | 71-43-2 | 0.005 | GAC PTA |
| Carbon tetrachloride | 56-23-5 | 0.005 | GACPTA |
| p-Dichlorobenzene | 106-46-7 | 0.075 | GAC PTA |
| 1,2-Dichloroethane | 107-06-2 | 0.005 | GACPTA |
| 1,1-Dichloroethylene | 75-35-4 | 0.007 | GAC PTA |
| Trichloroethylene | 79-01-6 | 0.005 | GAC PTA |
| 1,1,1-Trichloroethane | 71-55-6 | 0.2 | GACPTA |
| o-Dichlorobenzene | 95-50-1 | 0.6 | GAC PTA |
| cis-1,2-Dichloroethylene | 156-59-2 | 0.07 | GACPTA |
| trans-1,2-Dichloroethylene | 156-60-5 | 0.1 | GACPTA |
| 1,2-Dichloropropane | 78-87-5 | 0.005 | GAC PTA |
| Dichloromethane | 75-09-2 | 0.005 | PTA |
| Ethylbenzene | 100-41-4 | 0.7 | GAC PTA |
| Monochlorobenzene | 108-90-7 | 0.1 | GACPTA |
| Styrene | 100-42-5 | 0.1 | GACPTA |
| Tetrachloroethylene | 127-18-4 | 0.005 | GAC PTA |
| Toluene | 108-88-3 | 1 | GACPTA |
| 1,2,4-Trichlorobenzene | 120-82-1 | 0.07 | GAC PTA |
| 1,1,2-Trichloroethane | 79-00-5 | 0.005 | GACPTA |
| Xylenes (total) | 1330-20-7 | 10 | GACPTA |
(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 the contaminant's MCL.
| Contaminant | CAS number | MCL (mg/L) | BAT |
| Alachlor | 15972-60-8 | 0.002 | GAC |
| Atrazine | 1912-24-9 | 0.003 | GAC |
| Benzo[a]pyrene | 50-32-8 | 0.0002 | GAC |
| Carbofuran | 1563-66-2 | 0.04 | GAC |
| Chlordane | 57-74-9 | 0.002 | GAC |
| 2,4-D | 94-75-7 | 0.07 | GAC |
| Dalapon | 75-99-0 | 0.2 | GAC |
| Dibromochloropropane (DBCP) | 96-12-8 | 0.0002 | GACPTA |
| Di(2-ethylhexyl)adipate | 103-23-1 | 0.4 | GAC |
| Di(2-ethylhexyl) phthalate | 117-81-7 | 0.006 | GAC |
| Dinoseb | 88-85-7 | 0.007 | GAC |
| Diquat | 85-00-7 | 0.02 | GAC |
| Endothall | 145-73-3 | 0.1 | GAC |
| Endrin | 72-20-8 | 0.002 | GAC |
| Ethylene dibromide (EDB) | 106-93-4 | 0.00005 | GACPTA |
| Glyphosate | 1071-53-6 | 0.7 | OX |
| Heptachlor | 76-44-8 | 0.0004 | GAC |
| Heptachlor epoxide | 1024-57-3 | 0.0002 | GAC |
| Hexachlorobenzene | 118-74-1 | 0.001 | GAC |
| Hexachlorocyclopentadiene | 77-47-4 | 0.05 | GACPTA |
| Lindane | 58-89-9 | 0.0002 | GAC |
| Methoxychlor | 72-43-5 | 0.04 | GAC |
| Oxamyl (Vydate) | 23135-22-0 | 0.2 | GAC |
| Picloram | 1918-02-1 | 0.5 | GAC |
| Polychlorinated biphenyls (PCBs) | 1336-36-3 | 0.0005 | GAC |
| Pentachlorophenol | 87-86-5 | 0.001 | GAC |
| Simazine | 122-34-9 | 0.004 | GAC |
| 2,3,7,8-TCDD (Dioxin) | 1745-01-6 | 3 x10-8 | GAC |
| Toxaphene | 8001-35-2 | 0.003 | GAC |
| 2,4,5-TP (Silvex) | 93-72-1 | 0.05 | GAC |
Last updated April 28, 2023 at 2:20 PM
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