What are the major water quality concerns?
Chemical contamination of New Zealand supplies is always a risk, but usually it is a very small one. Most chemicals mentioned in the Drinking-Water Standards for New Zealand 2005 specify levels likely to cause adverse effects only after prolonged periods of exposure, so, with some exceptions, chemicals are not the main area of concern unless there is a major chemical spillage.
Throughout the world (and New Zealand is no exception) by far the most common problems arise from microbiological contamination of the source waters. Animal, bird and even human effluent, introduced in one way or another upstream from a water supply, can make that water unfit for consumption. Bacteria have always been of major concern, while protozoa such as Giardia and Cryptosporidium are increasingly being highlighted as causing ill health through drinking-water.
There are two ways of minimising the risk from these microbiological contaminants:
- Keep the source as clean as possible, by protecting the catchment and minimising the possibility of contamination.
- Treat the water to destroy any contaminants introduced.
- The most successful approach is to use both of these, and to regularly monitor the water quality to demonstrate that any risks are being controlled. Good systematic and ongoing risk management is important
Common Drinking Water issues
Water Quality which includes:
- Clarity (Dirty/Discoloured/Cloudy)
- Pressure or Flow (Low pressure/High Pressure)
- Continuity of Supply (No water)