Seneca reaps benefits from a forever contract that guarantees the city free water from Lake Keowee. But it costs to turn raw water into a safe and reliable product for drinking, cooking, and bathing. Last night the city council gave its mayor and the city administrator the authority to sign a contract for $8 million worth of improvements at its treatment plant on Normandy Shores. The contract goes to the Harper Corporation of Greenville. The Seneca treatment plant is permitted to produce up to 20 million gallons of water a day.