“Red” water is not always caused from iron in the source. Sometimes it is caused from excess corrosion occurring in the distribution system.   Testing for “red” discoloration at the source after final chlorination is the easiest way of determining whether the system is suffering from excess corrosion or from iron in the source.   Testing for iron chemically is only applicable if the samples are digested prior to running the iron test. In the event that there is no discoloration to the finished water then the system could be suffering from excess corrosion and a corrosion coupon test should be incorporated to determine the rate of corrosion.   Each aquifer  has certain chemical characteristics that tend to follow that aquifer throughout its length. Close values of alkalinity, iron, manganese, hardness and chloride can be indicative of a given aquifer. Consequently corrosion rates, scaling tendencies, and “red”/”black” water will also tend to follow that same water.   A sales representative should be able to provide the tests necessary to determine the cause of the “red” water.