Plans by South West Water to invest 850 million pounds in infrastructure and services are going out to public consultation.
Residents are invited to give feedback to the proposals, detailed on the company's website, until September 14th.
Locally the plans include new flood defences to protect the plant at Tiverton, improved sewerage in Exmouth and Exeter, and an upgrade of the sewage treatment plant in the Exe estuary to reduce the pollution risk.
The programme of work is due to take place between 2015 and 2020 - during which time bills are expected to rise to five hundred and 88 pounds.
Operations director Stephen Bird says the actual increase will depend on the work that's carried out - and the public can have their say on that.
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