Chlorination of Lower Hutt's water supply to continue

The recent chlorination of Lower Hutt’s water supply is to continue while investigations into the source of recent positive E.coli test results are underway.

A sample from a bore in the Waterloo wellfield returned a positive E.coli result on 12 April 2017. This was the third positive E.coli result in five months from water sourced from the Waiwhetu Aquifer. This, plus recent water quality testing across the aquifer showing an increasing amount of bacteria activity, has led to the decision to keep chlorinating the Lower Hutt water supply network while investigations are ongoing.

The public fountains at Buick Street (Petone) and Dowse Square (central Lower Hutt) have been closed as a precautionary measure because they can't be chlorinated.

Chris Laidlaw, Chair, Greater Wellington Regional Council said "The safety of our drinking water quality has not been compromised. We immediately chlorinated Lower Hutt's water supply in response to the recent positive E.coli test and we'll continue to chlorinate while we investigate the source of these positive results".

Dr Stephen Palmer, Medical Officer of Health at Regional Public Health said "In accordance with the Drinking Water Standards, Regional Public Health is notified of all events such as positive E. coli test results. We continue to work closely with Wellington Water and Hutt City Council to ensure the public health risk is properly managed".

Lower Hutt Mayor Ray Wallace said "There is no issue more important than the safety of our drinking water. We know many residents really value access to unchlorinated aquifer water but public safety will always be our number one priority and this means we will continue to chlorinate the water as a precautionary measure until we know more following the investigation".

Mark Kinvig, Acting Chief Executive, Wellington Water said "The cause of the positive E.coli result and increased bacterial activity isn't known at this stage and it may be related to the November 2016 earthquake. We're carrying out investigations into the source but this is expected to take many months to complete".

Additional information:

• Wellington Water delivers around 140 million litres of safe drinking water to the people of metropolitan Wellington every day
• A routine water quality test on water from a bore in the Waterloo wellfield (Lower Hutt) returned a positive E.coli result on Wednesday 12 April 2017. Other recent positive E.coli results were on 4 February 2017 and 2 December 2016.
• Chlorination of the water network in Lower Hutt was immediately initiated after each positive result
• About 70,000 customers in the Lower Hutt usually receive unchlorinated water supply. Residents of Wainuiomata, Stokes Valley and Manor Park already receive chlorinated water
• Wellington Water has a rigorous and thorough testing programme to ensure water is safe to drink
• Metropolitan Wellington's water comes from an aquifer, rivers, and, in times of shortage, storage lakes. Water from the rivers and lakes is chlorinated before delivery. Water from the aquifer usually isn't chlorinated
• The addition of chlorine to the water as a precaution against contamination means that the water doesn't need to be boiled before drinking

ENDS

For media comment:

Hutt City Council, 027 403 5348

More information - frequently asked questions on the chlorination of Lower Hutt’s water supply

1. If the recent water quality tests come back clear, why are you still chlorinating?

We are seeing a trend of increased bacteria activity in the aquifer which, together with the recent positive E.coli indicator test, we are treating as a signal for further investigation.

We're exercising a high level of precaution and are continuing to chlorinate the water we take from the aquifer while further evidence is gathered around why this is happening.

Public safety is our number one priority which means we have to chlorinate as a precaution.

2. What do the health authorities say?

Wellington Water is working closely with Regional Public Health. Regional Public Health is satisfied with the measures put in place to ensure the water is safe and advise that there is no need to boil it before drinking.

3. What is the history of positive E.coli test results in comparison to this year?

In the last five months, we've had three positive E.coli results in Lower Hutt. These are indicator tests and are a sign that further testing is needed. In all three cases, further tests came back negative.

However, most importantly, two of these recent positive results have come from the water source, not in the distribution network. Before December 2016, we hadn't ever had a positive E.coli result from the aquifer source. More specifically, there is also an increasing number of Total Coliforms (indicator bacteria) being found in the source water. This is an indication that something has changed within the aquifer and further investigation is needed.

Last five months:

• 12 April 2017 - positive E.coli test from Mahoe St bore. All further tests have been clear, chlorination remains in place. Bore taken out of service.
• 4 February 2017 - positive E.coli test from Naenae Reservoir. All further tests were clear, chlorination remained in place for three days of clear testing.
• 2 December 2016 - positive E.coli test from Colin St bore. All further tests were clear, chlorination remained in place for three days of clear testing. Bore remains out of service.

4. How long will the aquifer water be chlorinated for?

This depends on the results of Wellington Water's investigations. These investigations are expected to take a number of months to complete and the water sourced from the aquifer will remain chlorinated during this time.

5. Why did you close the public fountains at Buick Street (Petone) and Dowse Square (central Lower Hutt)? When will they be open again?

Public safety is our number one priority. We are seeing a trend of increasing bacteria activity across the aquifer which, together with the recent positive E.coli indicator test, we are treating as a signal for further investigation. We're exercising a high level of precaution and have closed the public fountains as they can't be chlorinated. They will remain closed while Wellington Water investigates, this is likely to take a number of months to complete.

6. Why didn't you shut the public fountains the first two times E.coli was found?

Only recently has the number of Total Coliforms found in the aquifer water been increasing. This, plus the third positive E.coli result in five months, led to the decision to keep chlorinating the Lower Hutt water supply network and to close the public fountains.

7. I haven't been feeling well for the past few days, could this positive E.coli result be the reason?

No. Your tap water has been and remains safe to drink. If you have any health concerns please see your doctor or contact Healthline (0800 611 116).

8. Is the water safe to drink for children and the elderly?

Yes, the tap water has been and remains safe to drink. If you have any health concerns please see your doctor or contact Healthline (0800 611 116).

9. Why can't the public fountains be reopened with a warning that this water should be boiled before drinking?

Public safety is our number one priority. As a precaution, the public fountains were closed as they can't be chlorinated. As part of their investigations, Wellington Water will be looking at non-chemical treatment options that will allow the public fountains to be reopened.

10. What are the investigations that Wellington Water is carrying out?

The investigations will be looking at a number of different aspects of the aquifer and the wellfield system.

11. When will the results of these investigations be known?

It may take a number of months before the results of these investigations become known. Updates will be available on Wellington Water's and Hutt City Council's websites.

12. How likely is it that the aquifer water will be permanently chlorinated?

A decision on the permanent chlorination of Lower Hutt's aquifer water has yet to be made. This decision depends on the result of Wellington Water's investigations and further discussions between Regional Public Health, Greater Wellington Regional Council, Hutt City Council and Wellington Water.

13. The earthquake was in November 2016, why have you waited until now (five months later) to decide the aquifer needs to be investigated?

Wellington Water has been carrying investigations into the aquifer since the earthquake. These investigations will take a number of months to complete.

14. How will you keep us updated on the situation?

Wellington Water and Hutt City Council will be updating their websites and Facebook pages on a regular basis.

15. Is this related to the November 2016 earthquake?

It may be as the recent positive E.coli results and the increasing bacterial activity in the aquifer water started after the earthquake. Wellington Water will be looking into this as part of their investigations.

16. Is this related to farming?

No, the aquifer is located below an urban area.

17. Is there any place in Lower Hutt to get access to unchlorinated water now?

No. If your water has a chlorine taste, try putting the water in a container or jug in the fridge (this helps the chlorine dissipate from the water). Boiling the water also helps take the chlorine taste out of the water.

18. Can people still drink water taken from the public artesian wells before it was closed?

Yes. Other water quality tests taken at the same time and since the positive E.coli test result have been negative. The public fountains have been closed as a precaution as they can't be chlorinated.

19. What if I have drunk water from the fountain recently?

Water quality tests at other locations taken at the same time as the positive E.coli test (and since) have been negative. The public fountains have been closed as a precaution as they can't be chlorinated. If you have any health concerns please see your doctor or contact Healthline (0800 611 116).

20. What role will central Government have in this?

Wellington Water is working closely with Regional Public Health. Regional Public Health is satisfied with the measures put in place to ensure the water is safe and advise that there is no need to boil it before drinking.

21. Is this issue similar to the water quality incident in Havelock North last year?

No. Havelock North had a number of unwell residents (that was traced to the water supply) while we have none. The elevated bacterial level in our aquifer water is an indicator that we need to investigate and we are taking a precautionary approach by chlorinating the water supply.

22. Now that chlorine has been added to our water supply, will fluoride be added to the water supplied to Petone and Korokoro?

Our focus is on investigating the positive E.coli test results and the increased bacterial activity in the source water. There are no plans to change the current fluoride status in Petone and Korokoro.

23. Who is responsible for the water network?

Each city council owns their respective reticulation network (i.e. Hutt City Council owns the reticulation network in Lower Hutt). Greater Wellington Regional Council owns the bulk water network and is responsible for the consents to take water from the Waiwhetu Aquifer. Wellington Water manages the entire water network on behalf of its five council owners (Greater Wellington Regional Council, Hutt City Council, Wellington City Council, Porirua City Council and Upper Hutt City Council).

24. Is this just a ploy to permanently chlorinate the water because it's easier to do?

No. A decision on the permanent chlorination of Lower Hutt's aquifer water has yet to be made. This decision depends on the result of Wellington Water's investigations and further discussions between Regional Public Health, Greater Wellington Regional Council, Hutt City Council and Wellington Water.