The other options are to either undertake minor or major rationalisation of the plants.

TasWater will hold information sessions and public consultation on the predicted $200 million sewerage improvement project from next week.

Asset management general manager Andrew Moir said yesterday, the project will focus on the planning of sewerage services for greater Launceston for the next 50 years.

``It is a service most people don't think about unless they haven't got it, but it's something which will shape the future of greater Launceston,'' Mr Moir said.

As it is, the system is outdated and `piecemeal', having been inherited over many years from smaller councils and most plants were more than 30 years old he said.

The plants were also not meeting environmental standards or a growing Launceston into the future he said.

Mr Moir said the project will be guided by community responses and form a business case to go to the board.

The plants located at Legana, Newnham, Riverside, Ti-Tree Bend, Hoblers Bridge, Norwood and Prospect Vale, treat more than 15,000 megalitres of sewage and wastewater for about 75,000 people annually.

Information sessions will be held at Legana, Mowbray, Kings Meadows, Riverside and Prospect Vale, from September 4.

For more information visit www.taswater.com.au, click on Community & Environment and then Water & Sewerage Improvement Projects.