Iron
What you need to know.
Source
Start from square one.
In most cases, iron contamination originates at the water source, with iron naturally entering into the raw water supply from the surrounding soil and rock. In fewer instances, iron contamination can arise from the corrosion of cast iron or steel pipes and fixtures within the water distribution system, contaminating the water as it moves from source to tap.
Key indicators
Orange/brown staining.
The most obvious sign of iron contamination is orange/brown staining on bathroom appliances, water fittings and laundry. Occasionally, the staining may be accompanied by orange/brown deposits.
When the iron concentration is particularly high, the water itself may also have an orange/brown discolouration and the water can take on a metallic taste.
Outside the home, iron contamination can be observed around the surface of the water source. For example, orange/brown deposits may be observed on surrounding soil and vegetation. The surface of the water can also develop an iridescent layer - similar to that of an oil spill - or accumulate a coating of scum.
The oxidation of iron as it becomes exposed to oxygen can also act as an energy source for iron bacteria to grow. This bacteria forms a slimy residue throughout the water system that can range from yellow to orange or red in colour, and can give water a damp or stale smell and taste.
Regulatory limit
Maximum level = 200μg/l
The regulatory limit for iron in drinking water is 200 micrograms per litre (200μg/l).
The World Health Organisation (WHO) doesn’t offer a health-based guideline for iron in drinking water because the water would fail to meet aesthetic standards much before becoming a health concern. Aesthetic acceptability includes the taste, smell and general appearance of the water. Basically, the water would be clearly undrinkable at unhealthy levels.
Aesthetics aside, the regulatory limit ensures that the water remains clean enough for UV (ultra-violet) disinfection units and other water treatment devices to work effectively. In UV units, iron particulate can quickly coat and stain its internal components, negatively impacting the performance of microbiological disinfection. This can lead to illness due to micro-organisms (such as bacteria and viruses) making it through to your taps.
Testing
It’s important to get the full picture.
As iron contamination can result in the buildup of iron deposits inside tanks and pipework, it can provide an ideal environment for iron bacteria and other microorganisms to grow. So, in order to design a solution that is both effective and economical, it’s important to get the full picture of what you’re dealing with by testing the water.
In the case of iron, prolonged exposure to oxygen when sampling can affect lab results, so we would recommend a trained individual take the sample.
Regular water testing should be conducted to check for any natural fluctuations in iron concentrations at the source, ensuring the ongoing effectiveness of your water filtration equipment.
