[Code of Federal Regulations] [Title 40, Volume 20] [Revised as of July 1, 2003] From the U.S. Government Printing Office via GPO Access [CITE: 40CFR143.3] [Page 621] TITLE 40--PROTECTION OF ENVIRONMENT CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PART 143_NATIONAL SECONDARY DRINKING WATER REGULATIONS--Table of Contents Sec. 143.3 Secondary maximum contaminant levels. The secondary maximum contaminant levels for public water systems are as follows: ------------------------------------------------------------------------ Contaminant Level ------------------------------------------------------------------------ Aluminum.................................. 0.05 to 0.2 mg/l. Chloride.................................. 250 mg/l. Color..................................... 15 color units. Copper.................................... 1.0 mg/l. Corrosivity............................... Non-corrosive. Fluoride.................................. 2.0 mg/l. Foaming agents............................ 0.5 mg/l. Iron...................................... 0.3 mg/l. Manganese................................. 0.05 mg/l. Odor...................................... 3 threshold odor number. pH........................................ 6.5-8.5. Silver.................................... 0.1 mg/l. Sulfate................................... 250 mg/l. Total dissolved solids (TDS).............. 500 mg/l. Zinc...................................... 5 mg/l. ------------------------------------------------------------------------ These levels represent reasonable goals for drinking water quality. The States may establish higher or lower levels which may be appropriate dependent upon local conditions such as unavailability of alternate source waters or other compelling factors, provided that public health and welfare are not adversely affected. [44 FR 42198, July 19, 1979, as amended at 51 FR 11412, Apr. 2, 1986; 56 FR 3597, Jan. 30, 1991]