Earthquake-damaged pipes in Wellington's central business district are leaking an estimated one million litres of water every day, and have been since November.

The lost water equates to almost half an Olympic swimming pool a day, and means average water usage in the central city has increased by roughly eight per cent, to hit about 16.5 million litres per day.

To help detect the leaks, Wellington Water has revealed plans to install 11 new bulk water flow meters across the CBD.

MONIQUE FORD/STUFF The large cavity, caused by a broken water pipe, was discovered under Featherston St in central Wellington in January.

But with deployment expected to take two years, it seems the water wastage will continue for some time yet.

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Keith Woolley, chief advisor for utilities company Wellington Water, said it was difficult to quantify and locate where drinking water was being lost in the capital city.

ROBERT KITCHIN/FAIRFAX NZ Chris Laidlaw, deputy chairman of Wellington Water governance committee, explains how freshwater is managed in Wellington.

"Leak detection is tricky at the best of times, but in the CBD where you have thick layers of concrete and constraints around working hours it's even more so," he said.

"The flow meters will also help identify problems such as low flow or valves that are closed or partially closed, and provide information to help with network planning for future growth."

A Wellington Water﻿ report has revealed that in the first two days after the 7.8 magnitude Kaikoura earthquake on November 14, which was felt strongly in Wellington, the leakage from busted pipes was seven-fold.

TALIA SHADWELL/FAIRFAX NZ A water main also burst in spectacular fashion near Wellington's Westpac Stadium on Boxing Day.

Seven million litres a day was being lost, mainly from broken pipes at the city's port.

This saw Wellington city's total water usage jump by 9 per cent.

A Wellington Water spokesman said it provided about 140 million litres a day to Wellington, Porirua, Upper Hutt and Lower Hutt, so "in the grand scheme" a leak of a million litres a day was not that much.

KEVIN STENT/FAIRFAX NZ Keith Woolley, from Wellington Water, said the rollout of 11 new flow meters would take two years.

"But it's not doing anyone any good if it's leaking, so we want to find and fix things," he said.

"Only the Wellington CBD showed that large a jump [in water use] after the quake, we think as a result of the movement in the foreshore area ... there were a few bursts in Hutt city that were fixed pretty quickly because they were much more visible."

On Boxing Day, a water main burst near Westpac Stadium, creating a fountain that was taller than the surrounding lamp posts.

In late January, Wellington came dangerously close to running out of water after a leak was found in the city's main supply pipe underneath Featherston St, near Wellington Railway Station.

The leaking water ate away at the ground underneath the road, creating a 10 to 15 cubic-metre hole - big enough to fit a people mover.

The first flow meter are expected to be installed in Wakefield St later this month. Meters are also planned for Market Lane, Arthur St and Abel Smith St before the end of June.

According to the water report, the Kingsley Pump Station also suffered damage in the November earthquake after three trees fall on it during a landslide. The station is now back in service following temporary repairs.

There was also some damage to both the Gear Island and Waterloo Water Treatment Plant equipment, which has been repaired with the exception of two bores.

During November, Wellington Water received nearly 1000 extra service requests - a 59 per cent increase.

AVERAGE DAILY WATER USAGE (past 30 days)

Wellington: 81.2 million litres

Lower Hutt: 38m litres

Porirua: 17.9m litres

Upper Hutt: 15.6m litres

Wellington region: 152.7m litres