What is Zinc?

Zinc is a naturally occurring metal in the earth’s crust and is well known to be an essential nutrient for human health.

However higher levels in drinking water can be a nuisance as they can affect taste and appearance of water.

NZ drinking water standards set a guideline value of 1.5mg/L for taste, with a note that it may affect appearance at 3.0mg/L.

How does zinc get into my water?

Zinc is commonly found in the ground, but is not very soluble so amounts from this are usually small.

Zinc is also a component is galvanised steel, which is is often used for bore casing. In bores with acidic water levels can sometimes rise to noticeable levels when new pipes is installed.

What does zinc do?

Zinc is not generally considered harmful, though high levels can lead to stomach cramps, nausea and vomiting.

Concerns with zinc in drinking water are generally that it can make water taste astringent and leave unsightly deposits.

How can remove zinc from my water?

If zinc is from new galvanised pipe, generally flushing is enough to reduce it to below nuisance levels.

Lower levels can be removed with activated carbon.

Higher levels in groundwater can be removed y cation exchange or coagulation.