A new £50 million water treatment plant could be built north of Plymouth as part of a flagship development by South West Water.
The state-of-the-art facility could be built at Roborough, sweeping away the plant at Crownhill, built in the 1950s.
The idea was in the firm's 25-year business plan published today, outlining investment that allows "gradual but not dramatic" price rises.
The Waterfuture: What's In the Pipeline document covers the 2015-2040 period and outlines how the water giant will tackle sewage infrastructure, floods and future investment.
Chief executive Chris Loughlin said the new multi-million-pound treatment works was one of a number of options on the table.
He said: "One of South West Water's priorities is to meet the water supply demands created by Plymouth's continuing expansion to the north. We are considering various long-term options, including a £50 million scheme to build a new state-of-the art treatment works in the Roborough area. "Potentially this could free up our current site at Crownhill for possible redevelopment."
While the document does not reveal how much the overall work will cost over the 25 years, customers are assured it will be spread over time.
The paper states: "Average bills are forecast to increase by around 0.5% per annum above inflation between 2015 and 2040 to pay for the investments that customers support and legislation requires.
"Changes in costs and the need for increased maintenance as assets age mean that in any five-year period customer bills could increase by more than this.
"We will target the timing of the investment programme over the next 25 years to allow gradual, rather than dramatic, changes to customer bills wherever possible.
"This will avoid placing a burden on a particular generation."
Company bosses said they want customers to comment on all aspects of the plan including future price limits.
They reminded customers that bills depend on a five-yearly price review with companies presenting their business plans to the industry's regulator Ofwat.
The next price review is in 2014 and will determine water bills for period from 2015 to 2020. South West Water supplies more than 700,000 households and 70,000 businesses across the region.
Some 415 million litres of water is distributed per day, with 480 million litres of waste water treated on a daily basis.
Mr Loughlin said first and foremost the company's strategy was designed to deliver the services customers depend on in the most cost-efficient and environmentally responsible way possible.
He said: "We've achieved a great deal over the last two decades. The challenge now is to build on that success.
"We must continue to meet the needs of a population that is set to grow significantly, while also ensuring that we can deal with the implications of extreme weather and increased legislation."
To view the document go to southwestwater.co.uk/waterfuture.