Discoloured water

Sometimes you might see discoloured water coming from your taps. If you notice this, the first thing you should do is run your outside tap for 20 minutes to see if the water runs clear.

If it doesn’t, call us on 06 356 8199 and we can flush the pipes around your property.

The discoloured water may stain clothes. We recommend you postpone doing the laundry until the water runs clear again.

If you notice a cloudy or white appearance in your tap water, don't be alarmed. This is common in many water supply networks and caused by tiny air bubbles in the water.

These bubbles form due to fluctuating pressures and flow rates in the pipes below the ground. When water is under high pressure in these pipes, air dissolves into it. Once you open the tap, the pressure drops, and the air comes out by appearing as tiny bubbles. Within a minute or two, these bubbles are released and your water clears up.

The cloudy appearance is not due to any additional chemicals in the water supply.

We only add chlorine and fluoride as required by national regulations and the Ministry of Health. We constantly monitor these levels to ensure the best possible safe drinking water for our everyone in our community.

Water supply routes and flow rates change constantly due to varying demands for water in different areas.

Additionally, routine and reactive maintenance, such as shutting valves or pipelines, can alter the flow of water through the pipes, leading to temporary changes in water appearance. That’s why your water may appear clear most of the time and only occasionally appear cloudy.

Smelly water

We add chlorine to our drinking water to kill harmful bugs and ensure it’s safe to drink.

This disinfection process is required by government regulations. Councils must maintain a minimum chlorine level of 0.2 mg/L in the water supply network, which is known as residual chlorine.

Sometimes, when chlorine levels are close to this minimum level, the smell or taste of chlorine may still be noticeable. While this can be unpleasant for some, the water remains completely safe to drink. People’s sensitivity to taste and smell varies, so some may notice chlorine more than others.

We’re aware that some parts of our network occasionally experience stronger chlorine odours. To address this, we regularly clean our pipes and are identifying long-term projects to further improve water quality.

If you’d like to reduce the taste or smell of chlorine:

  • Boil the water for 15 minutes.
  • Leave the water uncovered for 24 hours.
  • Consider installing a water filter for drinking water or your entire household supply.

Discolouration is caused by low levels of iron and manganese

These minerals occur naturally in the groundwater sources that supply parts of our network. When they contact chlorine (mandated by the government to disinfect drinking water) they can make the water appear yellow, orange, or brown.

Pipes that carry the water to your property develop a small layer of biofilm over time. The biofilm can trap some of the iron and manganese. This is occasionally released, causing discolouration.

The water is still safe to drink. However, we understand your concern and the inconvenience that discolouration causes.  We assure you that your health and safety remains our top priority.

Find out more about our drinking water supply and how we treat it before it gets to you to ensure it's safe to drink.

We flush the main city water pipes every year to ensure our water stays safe and pristine

Each year we clean the two main water supply pipes that get water from Turitea Dam to Palmy homes and businesses. This process is called swabbing and usually happens in August because we need to do it when the Manawatū River is in high flow.

We do this because the water from the dam has relatively high levels of dissolved iron and manganese. We remove most of this during the treatment process but over time the minimal remaining amounts can build up in the pipes. This doesn’t affect the safety of the drinking water. But it can cause it to become discoloured when it reacts with chlorine or due to changing pressures or flows within the pipes. Cleaning the pipes ensures this isn’t a problem.

The cleaning is done late at night when less water is being used.

All water mains within the city are flushed on a rotating yearly schedule. The two water mains supplying the city are flushed in alternating years.

We're also replacing old concrete pipes in the water main network with plastic ones.

Can I still use water while the pipes are being cleaned?

Yes, the water remains safe to drink, so you can still use water while we clean the pipes. We do this work at night so fewer people are using water. Try not to do your washing overnight though, as your clothes may be stained if the water is discoloured.

Some residents in Turitea won’t be able to use water, but those homes will receive a letter from Council.

How do you clean the pipes?

We start by shutting off certain valves (or taps) to the main pipe. This causes the water to be stuck behind these taps. We insert a giant sponge into the pipe. Then we open those doors and the pressure of the water pushes the sponge through the pipes. As it moves through the pipes it cleans them. Near the river, we remove the sponge so it doesn’t end up in our precious awa. The water and any sediment or biofilm is then flushed into the Manawatū River. Our consent conditions have very strict rules about when we can do this work to ensure the effects on our river are as minimal as possible.

Why does our water have manganese in it?

The water that goes through these pipes comes from our Turitea Dam, or from various bores across the city. Manganese is a mineral that naturally occurs in rocks and soil. We remove almost all of it during the treatment process, but tiny amounts are dissolved and still get through. Over time that can build up in the pipes. We remove it to ensure the city’s water supply isn’t discoloured.

The Ministry of Health has a health guide of manganese of less than 0.4mg/L. Palmerston North’s is typically 0.01mg/L, and we test it frequently.

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