Billions of litres continue to be lost from leaky Christchurch water pipes

Monday, 25 October 2021

In 2020/21, Christchurch used 57.1 billion litres of water collectively – and 23 per cent is estimated to have been lost to leakage.

Picture your bathtub filled with water. Now picture it in the world’s largest warehouse next to another 82 million water-filled bathtubs.

That is how much water is estimated to have leaked out of Christchurch’s drinking water pipes in the last financial year.

In 2020-21 the city, excluding Banks Peninsula, collectively used 57.1 billion litres of water. From this, the council estimates about 13.1b, or 23 per cent, was lost to leakage.

It is the highest amount lost in the last four financial years.

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The year before, in the 2019-20 financial year, 56.6b litres of water were used citywide – and 11.6b litres, or 20.5 per cent, were lost to leaks.

The council has a target of trying limit leaks to 15 per cent of the citywide water usage.

The goal, set in 2016, was “initially optimistic”, the council said, and it now thinks it is “impossible” due to “funding limitations”.

Pipe renewals have been postponed in recent years due to post-quake work and wellhead repairs in a bid to remove chlorine, the council said.

The new water loss data comes as the Government tries to push on with controversial water infrastructure reforms – which, if they go ahead, would take control of the pipes, reservoirs and other infrastructure away from councils and give it to large independent regional entities.

The Government says these new entities would be able to borrow two to three times the amount councils can, allowing the entities to invest more into infrastructure upgrades. Councils, however, are fearful about losing influence.

Even with the looming reforms, Christchurch’s city council has committed to spending $837 million towards drinking water infrastructure over the next 10 years in this year’s long-term plan.

Cr Pauline Cotter, who chairs the council committee responsible for water, said getting leaks from the water network under control was on the council’s radar.

The council’s water boss, Helen Beaumont, said the council was hitting a point now where different pipe materials, installed at different times, were reaching the end of their usable life.

A significant number of pipes would require renewal over a short period, she said.

The council’s water network is made up of just over 3500 kilometres of pipes.

Over half of these, about 1900km, were estimated to be in excellent condition at the beginning of October.

Another 460km – or 13 per cent of the network – are thought to be in the worst possible condition with an estimated remaining lifespan of just six years.

Beaumont said renewing older and poorer condition pipes was the most effective way to reduce leakage.

“The rate of renewals work has been much less than ideal since the earthquakes due to other calls on council’s finances.”

Beaumont said the council was now in a position to prioritise and increase the rate of renewals.

Christchurch residents will have to be more careful about their water use from mid-2022, when the council begins charging for excess use.

Between 20,000 to 30,000 households will likely be affected – about 13 to 20 per cent of households to which the council supplies water.

The council claims the charge has the potential to save $46m in infrastructure spending, as it would ultimately curb water demand and reduce pressure on the network.