The Wellington Regional Council is investigating ways to strengthen eight wells following a report warning that the Waiwhetu aquifer may not be able to pump clean water in the event of a serious earthquake.
It supplies about 40 percent of the region's water at present.
A report by GNS Science says more liquefaction than previously thought could occur at the well field if a major earthquake happened, affecting the aquifer's performance.
The council's general manager of water supply, Chris Laidlow, says it is looking into ways to overcome the situation. He says it can afford to have two wells out of action if a quake occurred but not six or even eight wells being inoperable.
A report to the council on options to strengthen the wells will be provided in March or April, he says.
