An investigation by the Audit Office suggests one in four city and district councils are poorly placed to meet expected demand for drinking water.
The study measured how well eight councils are providing drinking water now, and how they plan to do so in future.
The Audit Office describes the results of the study as variable, with the Central Otago and South Taranaki District Councils receiving a poor grade.
It says the snapshot of eight councils is representative of national trends.
Councils control potable water infrastructure worth $11 billion.
