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As part of its National Environmental Reporting Programme, the Ministry for the Environment regularly reports on water quality in groundwater aquifers. This information sheet presents the key findings from data collected from over 900 groundwater sites throughout New Zealand between 1995 and 2008.
As part of its National Environmental Reporting Programme, the Ministry for the Environment regularly reports on water quality in groundwater aquifers.
Data collected from over 900 groundwater sites throughout New Zealand between 1995 and 2008 was analysed for compliance with relevant guidelines and to identify national and regional trends.

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Map showing median nitrate for the period 1995 to 2008 for 914 groundwater sites in New Zealand. The majority (80%) of sites have median nitrate levels less than 5.65 mg/L. Forty four (5%) sites have median nitrate levels that exceed the drinking water guideline of 11.3 mg/L.

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| Region | % of sites with significant decreasing trend | % of sites with no significant trend | % of sites with significant increasing trend |
|---|---|---|---|
| New Zealand total | 11.85 | 68.17 | 19.98 |
| Auckland | 28.6 | 57.1 | 14.3 |
| Bay of Plenty | 7.5 | 86.8 | 5.7 |
| Canterbury | 5.9 | 64.3 | 29.8 |
| Hawke's Bay | 8.9 | 73.3 | 17.8 |
| Manawatu | 19.0 | 71.4 | 9.5 |
| Marlborough | 8.7 | 69.6 | 21.7 |
| Northland | 8.1 | 83.8 | 8.1 |
| Otago | 11.2 | 76.5 | 12.2 |
| Southland | 12.2 | 68.3 | 19.5 |
| Taranaki | 12.9 | 80.0 | 7.1 |
| Tasman | 18.8 | 56.3 | 25.0 |
| Waikato | 20.0 | 47.3 | 32.7 |
| Wellington | 19.7 | 74.6 | 5.6 |
| West Coast | 0.0 | 50.0 | 50.0 |
This information supports the Government’s New Start for Fresh Water work programme and other freshwater policy initiatives.
FOR MORE INFORMATION go to National Groundwater Quality Indicators Update: State and Trends 1995-2008








