Notice Type
Secondary Legislation
Notice Title

Aesthetic Values for Drinking Water Notice 2022

This notice issued pursuant to section 48(1) of the Water Services Act 2021 (“Act”) by the Chief Executive of Taumata Arowai–the Water Services Regulator (“Taumata Arowai”), acting under delegated authority, sets out aesthetic values that relate to drinking water.

This notice is secondary legislation as defined in the Legislation Act 2019.


1. Title

This notice is the Aesthetic Values for Drinking Water Notice 2022.

2. Interpretation

Within this notice:

determinand means a substance or characteristic that is determined or estimated in drinking water.

3. Commencement

This notice comes into force on 14 November 2022.

4. Purpose

Aesthetic values specify or provide minimum or maximum values for substances and other characteristics that relate to the acceptability of drinking water to consumers (such as appearance, taste, or odour). A drinking water supplier must take all reasonably practicable steps to supply drinking water that complies with aesthetic values issued by Taumata Arowai under the Water Services Act 2021.

These Aesthetic Values replace the guideline values for aesthetic determinands specified in the Drinking-water Standards for New Zealand 2005 (Revised 2018).

5. Aesthetic Values

The determinands and corresponding values listed in the Schedule are the aesthetic values that relate to drinking water.

Dated at Wellington this 14th day of June 2022.

RAYMOND McMILLAN, Chief Executive (Acting).


Aesthetic Values for Drinking Water

Determinand Value Unit Notes
Aluminium ≤ 0.1 mg/L Above this value, complaints of depositions or discoloration may arise
Ammonia ≤ 1.5 mg/L Odour threshold (alkaline conditions)
Calcium     See “Hardness”
Chloride ≤ 250 mg/L Taste threshold (counter ion dependent: sodium, calcium or potassium)
(contingent on the supply being chlorinated)
0.3 ─ 1.0 mg/L as Cl2 Free available chlorine
Taste and odour threshold (pH dependant)
Disinfection must not be compromised in trying to avoid taste and odour complaints
2-Chlorophenol ≤ 0.0001 mg/L Taste threshold
≤ 0.01 Odour threshold
Colour ≤ 15 TCU Appearance
Copper ≤ 1 mg/L Staining of laundry and sanitary ware
1,2-Dichlorobenzene ≤ 0.001 mg/L Taste threshold
≤ 0.002 Odour threshold
1,4-Dichlorobenzene ≤ 0.0003 mg/L Odour threshold
≤ 0.006 Taste threshold
2,4-Dichlorophenol ≤ 0.0003 mg/L Taste threshold
≤ 0.04 Odour threshold
Ethylbenzene ≤ 0.002 mg/L Odour threshold
≤ 0.08 Taste threshold
Hardness (total)
(Ca + Mg) as CaCO3
≤ 200 mg/L Scale deposition, scum formation (pH and alkalinity dependent)
Low hardness (<100) may be more corrosive
100–300 Taste threshold (Ca; counter ion dependent)
Hydrogen sulphide ≤ 0.05 mg/L Taste and odour threshold
Iron ≤ 0.3 mg/L Staining of laundry and sanitary ware
Magnesium     See “Hardness”
Manganese ≤ 0.04 mg/L Staining of laundry
≤ 0.10 Taste threshold
Monochlorobenzene ≤ 0.01 mg/L Taste and odour threshold
pH 7.0–8.5   Ideally 7.4 – 8.0. Most water with a low pH has a high plumbosolvency. Water with a high pH has a soapy taste and feel. A pH less than 8 is preferable for effective disinfection with chlorine
Sodium ≤ 200 mg/L Taste threshold (counter ion dependent)
Styrene ≤ 0.004 mg/L Odour threshold
Sulphate ≤ 250 mg/L Taste threshold
Taste and odour Acceptable to most consumers    
Temperature ≤ 15°C    
Toluene ≤ 0.03 mg/L Odour threshold
≤ 0.04 Taste threshold
Total dissolved solids ≤ 1000 mg/L Taste may become unacceptable from 600–1200 mg/L
Trichlorobenzenes (total) See below    
1,2,3-Trichlorobenzene ≤ 0.01 mg/L Odour threshold
1,2,4-Trichlorobenzene ≤ 0.005 mg/L Odour threshold
1,3,5-Trichlorobenzene ≤ 0.05 mg/L Odour threshold
2,4,6-Trichlorophenol ≤ 0.002 mg/L Taste threshold
≤ 0.3 mg/L Odour threshold
Turbidity ≤ 5 NTU Appearance
Xylene ≤ 0.02 mg/L Odour threshold
Zinc ≤ 1.5 mg/L Taste threshold