The following table shows the mean values of chemical analysis of the water supply from the Waterloo Water Treatment Plant, from 1 July 2019 - 30 June 2020, compared with the maximum allowable value (MAV) or guideline value (GV) for each element as set out in the Drinking Water Standards New Zealand (DWSNZ).

Notes: (A) MAV denotes the maximum acceptable value to comply with the Drinking-water Standards. (B) GV denotes the maximum guideline value in the Drinking Water Standards

 

Parameter

DWSNZ MAV (A) / GV (B)

No of samples

Mean value

Max value

Alkalinity - total g CaCO3/m³

-

13

55.307

63

Aluminium - total g/m³

0.1 (B)

15

0.0437

0.055

Arsenic - total g/m³

0.01 (A)

2

<0.002

<0.002

Boron - total  g/m³

1.4 (A)

2

<0.05

<0.05

Cadmium - total g/m³

0.004 (A)

2

<0.001

<0.001

Calcium Hardness g CaCO3/m³

-

13

44.615

53

Chloride g/m³

250 (B)

2

15.15

15.3

Chromium - total g/m³

0.05 (A)

2

<0.001

<0.001

Conductivity at 25°C mS/m

-

2

18.35

18.6

Copper - total g/m³

2 (A)

13

0.022

0.022

Cyanide g/m³

0.6 (A)

2

<0.005

<0.005

Fluoride g/m³

-

-

-

-

Hydrogen sulphide g/m³

0.05 (B)

2

<0.05

<0.05

Iron - total g/m³

0.2 (B)

13

0.093

0.125

Lead - total g/m³

0.01 (A)

2

<0.001

<0.001

Manganese - total g/m³

0.04 (A)

13

<0.013

<0.013

Mercury - total g/m³

0.007 (A)

2

<0.001

<0.001

Nickel - total g/m³

0.08 (A)

2

<0.001

<0.001

Nitrate - nitrogen g/m³

50 (A)

2

0.63

0.63

pH

7.0-8.5 (B)

15

7.853

8.1

Selenium - total g/m³

0.01 (A)

2

<0.005

<0.005

Silica g/m³

-

2

15.900

15.900

Sulphate g/m³

250 (B)

2

6.395

6.63

Total dissolved solids g/m³

1000 (B)

2

90

91

Zinc - total g/m³

1.5 (B)

13

0.033

0.033