Test results received last night conclude that Tokomaru Water Supply is compliant with New Zealand Water Standards and safe to drink.
Following expert advice from Taumata Arowai and Health NZ, Horowhenua District Council has lifted the Do Not Drink Water Notice effective immediately.
Results from 18 separate samples across the network show that earlier concerns relating to elevated levels of lead and non-compliance, were as a result of plumbosolvency caused by water reacting with older tapware. Consecutive results received from this enhanced testing regime conclusively show that testing to date has not found lead contamination in the source water or the reticulated water supply.
This is positive news for both the Tokomaru community and Horowhenua District Council to provide complete transparency, Council undertook two testing methodologies: testing the water before and after the tap was flushed. Tests came back clear at all locations across the network when we flushed the taps. When the tap was not flushed, and we took the first 150mls, we did have some samples that showed non-compliant lead levels – a reflection of the plumbosolvency which can occur when alloy reacts with water, particularly water that has been sitting for a long period of time in an alloy network.
Public Safety is our number one priority and while we may have caused our community concern and inconvenience, it was important that we had complete confidence that the water supply was and still is safe for drinking.
For some you may still have questions and concerns about the recent measures taken by Council. We encourage you to come to the Public Meeting at the Tokomaru Community Hall at 6pm on Monday 12 August, where we will have Council Staff, Elected Members and Health NZ Medical Officer of Health for MidCentral, Dr Rob Weir and Peter Wood from Taumata Arowai will be there to provide more information and answer any questions you may have. We will leave the water tanker in place over the weekend, until we have had the opportunity to meet with the community on Monday.
‘Hard’ versus ‘soft’ water
Water is considered hard or soft based on its amount of trace minerals. Tokomaru Water Supply (and many places in New Zealand) is classed as ‘soft’. This means for Tokomaru the water is more reactive to alloys (tap fittings). To mitigate this, further work will be ongoing to harden the water – in the case of Tokomaru, increase the ph level of the water, so that it is less reactive to tap alloys (tap fittings). This does not affect the safety of the drinking water.
Plumbosolvency
In many places in Aotearoa New Zealand, drinking water is plumbosolvent. This means the water can dissolve small amounts of metals it may encounter, such as lead and copper in your plumbing fittings (like pipes and taps).
Drinking water suppliers have a duty to ensure that the water they supply to you complies with the Drinking Water Standards, which sets maximum levels for metals in water. However, drinking water suppliers are only responsible for drinking water quality up to the point of supply, which is normally the toby outside of your property.
There may be metals in the plumbing within your property such as in the taps or other fixtures, which can have an impact after the water has been supplied. Taumata Arowai recommends:
- When you first turn on your tap in the morning, run your tap to fill a large cup of water.
- Tip the cup of water down the sink
- You should also do this at other times when your tap has not been used for a while, like when you come back from holiday.
This will help remove metals that might have been dissolved or absorbed from your plumbing fittings.
Flushing your drinking water taps is recommended for all households, whether on public or private water supplies.
Other places – including commercial businesses, community buildings, and schools – should also have systems in place to ensure that drinking water taps are regularly flushed, particularly after periods of not using them like after the weekend and school holidays.
What about other water supplies in the Horowhenua?
In light of the above, we want to provide additional certainty to our community. Routine samples taken on the 1 August from treated water at Levin, Shannon, Foxton and Foxton Beach Water Treatment Plants were all compliant with New Zealand Drinking Water Standards.
