Bosses at Northumbrian Water are hoping to get the go ahead for £900m of investment between 2015 and 2020.
The company, which supplies drinking water and waste water treatment to 2.7m customers in the north east, has submitted plans to water regulator Ofwat after more than two years of planning, research and consultation with customers.
The plan includes further improvements to the water environment and substantial proposals to help protect homes from the risk of flooding from sewers.
And officials say the average household bill will not rise more than inflation between 2015 and 2020.
Heidi Mottram, chief executive, said: “While we appreciate that any increases in the household budget are unwelcomed we believe that our plan will deliver the improved services our customers are quite rightly looking for.
“Given the economic situation, we have worked very hard to minimise the costs of delivering our plan and keep bills as low as possible.
“We have listened to our customers and produced a plan which balances the needs of our current customers, our future customers and is sustainable in the long term in protecting the environment.”
The plan includes improvements to the sewer network, investment in water treatment works and improvements to river and bathing waters.
Details of the business plan are at www.nwplanningforthefuture.co.uk