Tasmania's government says it can fix the state's ailing water infrastructure in five years but concedes it needs help from mainland workers to get there.

The government’s proposal to take over water and sewerage provider TasWater has been backed by a modelling report by Infrastructure Tasmania. It said the company’s 10-year plan to fix infrastructure could be completed in half the time, with $450 million of spending brought forward to 2022/23.  However the report, reviewed…