As rainfall percolates through the soil, iron in the earth’s surface dissolves into ferrous iron and rain transports it to our natural water supply. And yes, that means our private drinking water, too. Luckily, iron isn’t known to have any adverse health effects. It is, after all, an essential player in the production of red blood cells.
When an excess concentration of iron is reached, iron-fixing bacteria is known to thrive. They attain their energy from the oxidation of ferrous iron into its insoluble ferric form. Since only a small amount of energy is produced in this reaction, the bacteria needs to oxidize huge amounts of this free iron to proliferate. This produces iron precipitates and bacteria that emit a slime that can stain and clog your plumbing. These bacteria can also cause turbidity, odor and staining of water.
So, how do you know if this red stuff really is iron-fixing bacteria? Just take an empty water bottle and fill it with a sample, then wait 24 hours. If the bacteria are present, you’ll see suspended clumps of iron-colored substances!
Next time you come across this, don’t worry! It’s probably just iron bacteria.