Iron bacteria can produce a slimy rust-colored mass on plumbing fixtures and any surface in contact with water containing these organisms. Iron bacteria give an unpleasant taste and odor to the water, discolor and spot fabrics and plumbing fixtures, reduce water flow through pipes, and clog pumps (Manual of Small Public Water Supply Systems; EPA570-9-91-003; May 1991). While the aesthetic problems caused by iron bacteria in drinking water may not directly represent a public health risk, the appearance of aesthetic problems may signal pipe deterioration or other issues that may represent, or lead to, a health concern (Health Risks from Microbial Growth and Biofilms in Drinking Water Distribution Systems, June 17, 2002). EPA has not set a standard for iron bacteria in drinking water.
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 .