TEST

TYPICAL RANGE

NZDWS 2005 Maximum Acceptable Value (MAV)

Significance

pH

5.5 - 7.5

7.0 - 8.5 (Guideline Value)

Groundwater that is low in pH can attack copper piping leading to high levels of dissolved copper.

Conductivity

NA

<1500us/cm

Important for ion balance check and other parameter estimation. Used to calculate TDS.

TDS

10-500mg/L

<1000 mg/L

Bores close to the ocean can have elevated levels. Water from limestone aquifers can also be high in TDS.

Alkalinity

NA

NA

Important for interpretation and other parameter estimation.

Calcium

NA

NA

Major ion, used to calculate hardness.

Magnesium

NA

NA

Major ion, used to calculate hardness.

Hardness

0.1 - 2 mg/L

<200 mg/L

High hardness may cause scale deposition and scum formation. Water with low hardness (<100) may be more corrosive.

Sodium

NA

<200 mg/L

Major ion, indicative of salt water intrusion, can cause taste problems.

Potassium

NA

NA

Major ion.

Nitrate

NA

<11.3 mg/L

Important nutrient indicative of fertiliser application and other anthropogenic inputs, health concern (can cause methaemoglobinaemia in bottle fed infants)

Chloride

NA

<250 mg/L

Major ion, indicative of salt-water intrusion, can cause taste and corrosion problems.

Sulphate

NA

<250 mg/L

Major ion, can cause taste problems.

Boron

NA

<1.4 mg/L

Has been detected in some bores from Geothermal sources.

Iron

0.1 - 2 mg/L

<0.2 mg/L

High iron is not a health issue, but can lead to staining of laundry and sanitary ware.

Manganese

<0.05 mg/L

<0.04 mg/L

<0.10 mg/L
<0.4 mg/L

Staining of laundry

Taste Threshold
Health MAV

Copper

NA

<2 mg/L

Can be leached from copper piping by acidic/corrosive water.

Zinc

NA

<1.5 mg/L

Can be present due to galvanised metal piping.

EColi

Not usually detected

<1 in 100mL of sample

Generally not an issue for groundwater but can be detected in shallow bores.