California Code of Regulations
Title 22 - Social Security
Division 4 - Environmental Health
Chapter 15 - Domestic Water Quality and Monitoring Regulations
Article 4 - Primary Standards-Inorganic Chemicals
Section 64431 - Maximum Contaminant Levels-Inorganic Chemicals
Public water systems shall comply with the primary MCLs in Table 64431-A as specified in this article.
Table 64431-A
Maximum Contaminant Levels Inorganic Chemicals
| Chemical | Maximum Contaminant Level, mg/L | |
| Aluminum | 1. | |
| Antimony | 0.006 | |
| Arsenic | 0.010 | |
| Asbestos | 7 MFL* | |
| Barium | 1. | |
| Beryllium | 0.004 | |
| Cadmium | 0.005 | |
| Chromium (hexavalent) | 0.010 | |
| Chromium (total) | 0.05 | |
| Cyanide | 0.15 | |
| Fluoride | 2.0 | |
| Mercury | 0.002 | |
| Nickel | 0.1 | |
| Nitrate (as nitrogen) | 10. | |
| Nitrate+Nitrite (sum as nitrogen) | 10. | |
| Nitrite (as nitrogen) | 1. | |
| Perchlorate | 0.006 | |
| Selenium | 0.05 | |
| Thallium | 0.002 |
* MFL=million fibers per liter; MCL for fibers exceeding 10 µm in length.
Note: Authority cited: Sections 116270, 116271, 116293(b), 116350, 116365, 116365.5 and 116375, Health and Safety Code. Reference: Sections 116365, 116365.5 and 116470, Health and Safety Code.
Note: Authority cited: Sections 116271, 116293(b), 116350, 116365, 116365.5 and 116375, Health and Safety Code. Reference: Sections 116365, 116365.5 and 116470, Health and Safety Code.
