Thames Water has branded its proposed £1billion reservoir near Abingdon as essential.
Thames Water's chief executive David Owen said building the reservoir, on farmland between between Abingdon and Wantage was crucial but some residents whose homes are in the area are opposed to the plan and have campaigned against the development for years.
Nick Thompson, a spokesman for residents, said Thames Water had been able to spend millions of pounds alone researching plans for the reservoir.
Mr Owen said: "The reason why we are launching these plans is so everyone can have their say.
"Ultimately the comments people make will go into a report to the Secretary of State, and it will be his decision on whether the reservoir can go ahead."
Meetings with residents are expected to take place in the coming months in Abingdon, Grove and Wantage.
A statement on Thames Water's website www.thameswaterconsult.co.uk says the plan covers a 25-year period from 2010 to 2035.
It adds: "The draft Plan sets out how we plan to ensure there will be sufficient water available to meet our customers' needs over the next 25 years."
Customers can read the consultation document on the website, and give their comments. The consultation is open until to August 27.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article