Frequently Asked Questions
Below you will find information that might help you understand how to find things or learn about information you might need to know about your city or town.
Iron & Manganese
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Iron & Manganese
Iron and manganese are metals that occur naturally in soils, rocks, and minerals. In the aquifer, when groundwater comes into contact with these solid materials it begins to dissolve them. This releases their constituents, including iron and manganese, into the water.
In California, the State Water Resources Control Board, Division of Drinking Water sets Secondary Maximum Contaminant Levels (MCLs), also known as "Consumer Acceptance Contaminant Levels" for those constituents in water that may adversely affect the aesthetic qualities of drinking water, such as taste and odor. The following table is excerpted from Division 4, Chapter 15, Article 16, Section 64449 of the California Code of Regulations, Title 22
Constituent Maximum Contaminant Level/Units Aluminum 0.2 milligrams per liter (mg/L) Color 15 Units Copper 1.0 mg/L Foaming Agents (MBAS) 0.5 mg/L Iron 0.3 mg/L Manganese 0.05 mg/L Methyl-tert-butyl ether (MTBE) 0.005 mg/L Odor-Threshold 3 Units Silver 0.1 mg/L Thiobencarb 0.001 mg/L Turbidity 5 Units Zinc 5.0 mg/L Iron and Manganese can be problematic at levels above Secondary MCLs because they both impart color to the water, which can in turn stain plumbing fixtures with rusty, reddish-brown deposits. In addition, Manganese at very high levels can pose a neurotoxic risk. Additional information about Manganese in drinking water can be found online.
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Iron & Manganese
Yes. The District operates nine treatment plants to reduce the amount of Iron and Manganese delivered to customers. The treatment plant technology is based on oxidation with sodium hypochlorite (chlorine bleach) followed by filtration through filter media containing anthracite and sand, pyrolusite, or greensand.
The District's Iron and Manganese treatment plants successfully achieve roughly 95 to 99% removal of the iron and manganese content of the raw groundwater. The color value of water entering the distribution system is considered Not Detectable (ND).