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Wellington Water’s changes to limit water waste this summer

Wellington Water’s changes to limit water waste this summer

Last year, Wellington’s water system was leaking like a sieve.
Photo: RNZ / Samuel Rillstone

This time last year, the Wellington region was in a very risky situation.

Wellington Water was warning the Hutt Valley, Porirua and the City of Wellington that there was a serious risk of water shortages.

This is not due to a particularly scorching summer or a major water pipe break that sent thousands of liters of water into the sea.

This was due to a water network that, after decades of underinvestment, had leaked like a sieve, meaning almost half of the region’s water was lost.

The risk of water shortages has prompted residents to cut back on consumption and rush to buy 200-litre tanks sold by councils – with demand causing a queue at the Wellington council tip shop.

At one point last year there was a 70 percent chance the region would be plunged into level three restrictions which would have banned all water use outside residences and asked households to reduce their indoor water consumption.

This year things are different and the chances of the measures being put in place are 1 percent.

But how did they do it?

Wellington Water’s director of regulatory services Charles Barker told RNZ the company started by repairing thousands of leaks throughout the year.

“By this summer, we envisage that all of our councils will have reached this sustainable level (of leaks), which is a phenomenal effort compared to where we were at this time last year.

“In fact, as far as we know, there will be more leaks on the private network, which is the home side of the network, than on the public side.”

The other major factor in the decrease in water pressure this summer was the upgrade of the Te Mārua water treatment plant, Barker said.

Upper Hutt supplies 45 per cent of the Wellington region’s water.

RNZ reported in March that an upgrade to the plant to increase the amount of water it can supply from 80 megalitres per day to 140 megalitres per day had cost more than $40 million.

Improvements to the Te Marua water treatment plant have helped ease pressure on the water supply.
Photo: Provided

The first stage of this project is now complete and can add a further 20 megalitres per day to the network.

That allowed the plant to draw more water from its supply lakes, Barker said.

“To put that in context, that’s about another 10 percent of our total processing capacity across the network, so that’s a substantial influence.”

The third element of Wellington Water’s summer recovery has been the watchful eye of Taumata Arowai.

In March, the water watchdog was not convinced the “acute risk of water shortage” would be avoided this summer – so it wrote a letter to Wellington Water asking it to develop a plan to avoid it.

The organizations have set a target of reducing overall water demand (this includes water loss and consumption) by 7.4 million liters per day by February next year, which Wellington Water s is set as a goal to achieve.

Taumata Arowai’s need to set goals was helpful, Barker said after reflection.

“Don’t just cut back, but set strict goals.”

He told RNZ they weren’t out of the woods yet when it came to summer water shortages.

To provide long-term certainty in the space they needed, they needed to focus on renewing pipes rather than repairing leaking pipes, he said.

“If you’re repairing a rusty panel on your car, you can often only cut a small piece off before it’s actually more efficient to replace the panel and that’s where we need to be.”

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