Testing Procedures for Iron and Manganese
In this section we will answer the following question:
Read the online lesson.
A water analysis should be done to determine the source of the iron and manganese. Iron and manganese may be present in the water supply or be caused by corroding pipes (iron or steel). Iron from pipe corrosion indicates low pH that may need to be corrected. Generally, you should take the sample from the faucet closest to the pumps. Allow the water to run for 5-10 minutes before sampling to obtain fresh water that has not been exposed to air. Do not sample water that has gone through a water heater or a water treatment unit such as a softner. If the water is clear when first drawn, but red or black particles appear after the water settles, dissolved iron and manganese are present. If the water has a red tint but no particles settle out after a time, colloidal iron is the cause. Reddish brown or black brown slimy masses inside the toilet tank indicate iron or manganese bacteria. Laboratory tests are recommended in all cases to determine iron and manganese concentrations.
Testing Public Water Supplies
The quality of water supplied by Public Water Systems is regulated by the U.S. Environmental Protection Agency (EPA) under the Federal Safe Drinking Water Act. This includes any well with 15 or more service connections or that regularly serves 25 or more people.
Public drinking water standards established by EPA fall into two categories - Secondary Standards and Primary Standards.
Secondary Standards are based on aesthetic factors such as taste, odor, color, corrosivity, foaming, and staining properties of water that may affect the suitability of a water supply for drinking and other domestic uses.
Primary Standards are based on health considerations and are designed to protect human health. Iron and manganese are both classified for human health reasons under the Secondary Maximum Contaminant Level (SMCL) standards, indicating that they are not regulated by either the Federal or State Drinking Water Acts. If your water comes from a public water supply, contact the water utility office to inquire about the iron and manganese levels in your water.
Testing Private Water Supplies
Water quality in private wells is not currently regulated at the federal or state level. thus, the regular testing of a private water supply is not required under state or federal law. If consumers want to know the concentration of dissolved iron and/or manganese in a private water supply, they will need to have the water tested at their own expense. If foul odor (which is not a rotten egg smell) and a red or black slime layer is found in places like the toilet bowl or reservoir, then individuals should also request to have the water tested for iron and manganese bacteria. Tests to determine the presence of iron or manganese, and of iron and manganese bacteria in drinking water should be done by a laboratory utilizing approved EPA methods for the detection of iron and manganese.
Interpreting Test Results
Public Water Supply Test Results
The Secondary Maximum Contaminant Level (SMCL) for iron in drinking water is 0.3 mg/L, sometimes expressed as 0.3 ppm, and 0.05 mg/L (ppm) for manganese. Water with less than these concentrations should not have an unpleasant taste, odor, appearance or side effect.
Private Water Supply Test Results
Since EPA regulations do not apply to private drinking water wells, users of private drinking water typically evaluate iron and manganese based on the degree of nuisance of these dissolved metals. They may also consider the EPA guidelines of 0.3 ppm iron and 0.05 ppm manganese and the presence or absence of iron and/or manganese bacteria in assessing the degree of nuisance associated with their water supply.
Answer the questions in the Lesson 3 quiz . When you have gotten all the answers correct, print the page and either mail or fax it to the instructor. You may also take the quiz online and submit your grade directly into the database for grading purposes.