Frequent Questions

What can cause tap water to appear red, brown, or orange?

Iron can cause water to appear reddish-orange.  Iron combines with oxygen to form reddish-brown particles in water that produce rusty brown stains on plumbing fixtures, fabrics, dishes, and utensils.  Large concentrations of iron can produce iron sediments or deposits in the water.  Iron also produces a noticeable bitter, metallic or astringent taste in water, food, and beverages such as coffee and tea coffee (Manual of Small Public Water Supply Systems; EPA570-9-91-003; May 1991).  The daily nutritional requirement for iron is 1-2 mg, however the average diet contains 16 mg.  The amount of iron causing discoloration of tap water is a small fraction of the normal daily intake and does not have toxicological significance.  EPA has set a non-enforceable secondary maximum contaminant level of 0.3 mg/L to prevent most aesthetic effects (National Secondary Drinking Water Regulations; EPA570-9-76-000; June 1984). 

To help determine the cause(s) of aesthetic or cosmetic effects from your drinking water, contact your local drinking water system.  Additional guidance for household well owners is available at http://water.epa.gov/drink/info/well/index.cfm.  General information on nuisance chemicals is available at http://water.epa.gov/drink/contaminants/secondarystandards.cfm .

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