A report from Wellington Water - the authority which oversees the network for the entire region - has set the figure, to replace 60 percent of the 2000km pipe network.
How the money will be accrued is yet to be determined.
It comes after Porirua City Council received a similar report, which put their bill at $2b.
"We have a situation here where we have a trifecta of issues," said Hutt City Mayor Campbell Barry. Read More