Plans to build a massive reservoir in Oxfordshire are being debated by residents on Wednesday night.
Locals are meeting to discuss the implications of a plan by Thames Water to build the reservoir on land between Wantage and Abingdon.
The proposed site, close to Steventon, could be as large as 10 sq km (3.9 sq miles) and cost an estimated £900m.
The company is currently carrying out environmental studies before deciding whether to seek planning permission.
A company spokesman said: "Thames Water's current provisional preference is for a reservoir, south west of Abingdon.
"Population growth in London and the south east, growing demand for water, and climate change mean that we expect a new major source of water to be needed by around 2020.
"Our key focus remains reducing leakage, but even the major improvements envisaged in our latest plans will not alone be sufficient to meet the growing demand for water in our region."
People living around Steventon are concerned about the impact of such a massive building project and are asking the company to give them more information about its plans.