Taste and Odour issues FAQs

With the start of summer as river levels drop we often start getting complaints about the taste and odour of the drinking water and concerns that the water Council provides is unsafe.

Council would like to assure people that despite any taste or odour issues all Council supplied tap water is 100% safe and will not cause people to be ill.

Our rivers are living things and the taste and odour is affected by naturally occurring organic compounds such as algae and diatoms. These become more concentrated during periods of low water flow and warm weather. There is nothing Council can do to prevent these growths occurring nor would we want to as they are part of the natural ecology of the river.

Taumarunui has always experienced water taste and odour problems and we have been dosing the water with carbon which is helping improve the situation.

This is not a money issue as Council will continue to spend whatever we need to ensure that our communities continue to have clean, safe drinking water. Getting the balance right is an on-going process of trying things, sampling and testing that takes time.

Council and our water contractor Veolia welcome the feedback and encourage people to continue to advise us of any issues they are experiencing. It would be helpful if people experiencing taste and odour issues call Council and let us know to allow us to run tests on the reticulation line.


Q. Why are there taste and odour issues with the water?

Our rivers are living things and the taste and odour is affected by naturally occurring organic compounds such as algae and diatoms. These become more concentrated during periods of low water flow and warm weather. There is nothing Council can do to prevent these growths occurring nor would we want to as they are part of the natural ecology of the river.

Q. Can Council fix the taste and odour issues?

Not completely all of the time. As a natural ecological system our rivers are constantly changing and Council with our water contractor Veloia need to constantly work to keep things in balance. In extreme weather events (either low river flows or floods) this is more difficult to do.

In Taumarunui we carbon dose the water to help remove the taste and odour. The carbon works by bounding with the organic particles which is then filtered out. Ironically, when the water is running very clear after long still periods there is not much for the carbon to bound too which makes it less effective.

Sampling of both the raw water line and the treated water to try and determine how well the carbon is working has shown that adding extra carbon when the river is very low like it has been doesn't help the taste and odour issues much.

Also when we have been carbon dosing at full capacity like we have recently this has caused other operational issues as the carbon is blocking up the filters.

Everyone should also run their taps for a few minutes at the start of each day. This can help reduce any buildup of matter that can contribute to taste and odour issues.

Q. Are you trying anything new to help with taste and odour issues?

Yes.  Council's water contractor Veolia is involved in an on-going process of trying things (such as different carbon types), sampling and testing. Finding the correct balance with varying conditions is challenging. 

Q. Is the water safe to drink?

Absolutely. Despite any taste or odour issues all Council supplied tap water is 100% safe and will not cause people to be ill.

Council's water contractor Veolia Water takes water samples daily for testing from alternating points around the reticulated (pipe) water network as well as a weekly test for E.coli bacteria.

The daily water samples are tested for four key factors being; free available chlorine which is a measure of the chlorine left in the water after treatment, the pH level which is a measure of alkalinity and acidity, water temperature which affects the pH level and turbidity which is a measure of organic material in the water

Tests for E.coli bacteria are undertaken once a week and performed at an independent laboratory. Results show no E.coli are present in our water supply.

Q. Why are we spending money on district promotion or township revitalisation when we can't fix the water taste and odour?

This is not a case of either or. Council will spend what it needs to on ensuring our communities continue to have clean, safe drinking water.

We are doing all we can and have the resources we need, however, as a natural ecological system our rivers are constantly changing and we need to constantly work to keep things in balance. In extreme weather events (either low river flows or floods) this is more difficult to do.

This is an on-going scientific process of trying things, sampling and testing.

Q. When the water flow gets low why doesn't Council stop people taking water from the river?

Horizons Regional Council have jurisdiction over all water allocation. Ruapehu District Council needs a resource consent like anyone else that determines how much water we can take from any river.

The hydroelectricity sector is by far the largest user of water in Horizons' Region, with an estimated average use of 55 m3/s or 4,752,000 m3/day (SoE Report, Horizons 2005a). The combined maximum daily consented rate from groundwater and surface water for all other uses combined accounts for 1,647,665 m3/day or approximately 19 m3/s.

Q. What impacts river levels?

River levels are governed by atmospheric conditions (the weather) including rain and snow melt.

When it rains in town this does not impact on the town water supply.

Q. What about the water bottling plant?

The water bottling plant in National Park draws its water from a private bore. It does not affect the water flow for any town water supply.

Q. How are water quantities for usage and consumption decided?

Council has resource consent to take so much water per day from each river based on the population we serve e.g. We can take 7,000 cubic meters per day from the Whanganui River.

On average on adult is thought to use between 240-250 litres of water per day. This includes drinking water, personal hygiene, washing machine, washing dishes, etc.

Q. Why are water restrictions put in place?

Water restrictions come into force automatically when a minimum river flow rate is reached.

  • For the Whanganui River the minimum river flow rate is 29 cubic meters per second.
  • For the Makotuku River the minimum river flow rate is 0.115 cubic meters per second.

Water restrictions also impact on how much water we can take out of the river. Our resource consent require us to use our water wisely and we must demonstrate efficient and effective use. If we don't need the water it should stay in the river. Council takes best practical steps to comply with our resource consent without compromising public health.


​Our rivers are living things and the taste and odour of tap water is affected by naturally occurring organic compounds such as algae and diatoms that become more concentrated during periods of low water flow and warm weather.

Page reviewed: 12 Oct 2018 2:49pm