What does safe drinking water mean?
Safe drinking water is water that is free from microbiological and chemical contamination as outlined in the “Drinking Water Standards for New Zealand 2005”. This applies particularly if you live rurally and get your own water from either rain water, surface water or groundwater which is less than 30 metres deep. Each of these sources have their own issues:
Rain water: while this water is generally good quality, faecal matter from birds, possums etc in the gutters and roofs where the water is being collected can easily contaminate the water and the bacteria from the contamination then is throughout the water tank and plumbing system.
Surface water: this is collected from streams, lakes or rivers and has the same contamination issues as rain water, as well as silt contamination from surface run off.
Ground water: this is water collected underground via a well, bore or spring. Again, whilst it can be good quality it also is subject to faecal matter from animals, mineral and metals contamination such as iron, magnesium or calcium, nitrate contamination due to the use of fertilisers on the ground above or it can taste salty due to seawater intruding.