Water Quality
Water supply gradings
The Ministry of Health produces the Register of Community Drinking-Water Supplies in New Zealand, which uses two gradings.
Source and treatment grading
Based on source and treatment factors |
Distribution zone grading
Based on reticulation condition, management, and actual water quality |
| A1 |
Completely satisfactory, negligible level of risk, demonstrably high quality |
|
|
| A |
Completely satisfactory, very low level of risk |
A |
Completely satisfactory, negligible level of risk, demonstrably high quality |
| B |
Satisfactory, low level of risk |
B |
Satisfactory, low level of risk |
| C |
Marginal, moderate level of risk, may be acceptable in some smaller communities |
C
|
Marginal, moderate level of risk, may be acceptable in some small communities |
| D |
Unsatisfactory, high level of risk |
D |
Unsatisfactory, high level of risk |
| E |
Completely unsatisfactory, very high level of risk |
E |
Completely unsatisfactory, very high level of risk |
| U |
Ungraded |
U |
Ungraded |
Rotorua’s water supplies gradings (2008):
| Central Urban |
Ee |
| Eastern Area |
Ed |
| Hamurana |
Ee |
| Kaharoa |
Ee |
| Mamaku |
Da |
| Mihi |
Db |
| Ngongotaha |
Da |
| Okareka |
Da |
| Reporoa |
Ee |
| Rotoiti |
Da |
| Rotoma |
Da |
Complying with standards
Council works to ensure that all supplies comply with the Drinking Water Standards of New Zealand (DWSNZ 2005) revised (2008).
Disinfection
In the Rotorua District our water is extremely clean and requires little treatment. Water Supplies are disinfected using chlorine treatment.
Council adds a small amount of chlorine (0.4mg/l) to all supplies except Eastern. UV treatment plants are being installed on all supplies except Mamaku to comply with the DWSBZ 2005 (Revised 2008).
Fluoridation
We do not fluoridate any of the Rotorua District’s water supplies.
Water issues
Problem: Yellow to rusty brown water, stains on washing Small particles in the water or stale taste
Cause: Rusting iron pipes at home or sediment in the water supply
Turn a tap on full for a couple of minutes. If the water turns clear, the brown colour is probably due to rusting iron pipes at home. The pipes may need to be replaced with plastic or copper pipes.
If the water does not clear or still tastes stale after turning the tap on full, the problem is not in your pipes. Small particles settle at some places in the water system. Dirty water results if this sediment is disturbed in some way. Contact Council and we will arrange to have the supply mains cleaned and flushed.
Problem: Metallic taste or smell
Cause: Corroding pipes or fitting (plumbosolvency)
Plumbosolvency is when minute traces of the metals in your pipework and fittings leach into the water when it is not being used. Turn a tap on full for a couple of minutes.
Problem: Green or blue water, green stains on plumbing
Cause: Corroding copper pipes at home
Problem: White, cloudy or milky water
Cause: Air in the water
If you hold up a glass up to the light, there will be tiny bubbles moving up from the bottom of the glass. This is not harmful. Council can flush the mains to get rid of the air if the problem continues. Calcium has been leached from cement-lined pipes. This often improves with time.
Problem: Slight smell of chlorine
Cause: Chlorine in the water
Council adds chlorine to disinfect the water. This is not harmful and the smell will not continue for long.