Wellington is losing up to 1.5 million litres of water a day because of earthquake damage to pipes.
The region's provider, Wellington Water, said that since November's big earthquake, the amount of water being taken daily has risen by nearly 10 percent.
The capital was shaken by a 7.8-magnitude earthquake on 14 November. Kaikoura, and the surrounding areas, was worst hit, but Wellington was also badly impacted, with damage to many buildings.
A chief adviser, Keith Woolley, said the city was definitely losing drinking water but it was difficult to know exactly where.
Leak detection was a difficult task, but even more so in the central business district because of thick layers of concrete and constraints on working hours
He said the company was going to install flow meters on mains pipes in the central city to make it easier to find the leaks.
The work will take two years.