The United Nations is appealing for millions of dollars in aid for Sri Lanka to compensate those who have been affected by floods.
At least 32 people were killed in the floods and officials say about 200,000 people are still displaced, many living in makeshift camps which at the height of the crisis housed 340,000 people.
Flood waters are now receding in the worst-hit areas in eastern and central Sri Lanka.
UN official Mervyn Fletcher says making sure people have clean drinking water is a major problem.
He says at least 60,000 wells have been contaminated, and wells are a major source of water for the community.
Mr Fletcher told the BBC that he had visited properties where there had been at least two metres of water washing through them.