Tasmanians face a price rise of 27 per cent over the next six years under a plan to improve water quality through upgraded plants.

TasWater will roll out a scheme of works to renew or refurbish water and sewerage infrastructure which aims to supply clean drinking water across the state, including to 24 towns which currently have to boil water before it is safe to drink.

TasWater chairman Miles Hampton confirmed that the works will come at a cost: a 15 per cent increase over three years, followed by a 12 per cent hike over the next next three years.