Water companies have been questioned about their plans for tackling a possible water shortage this summer, after long periods of low rainfall.
Bosses of South East, Southern and Thames Water were asked by the head of the Environment Agency about plans to manage demand.
They discussed sharing water between regions and reducing the millions of litres that leak from their networks each day.
River and groundwater levels are below average in many areas because last year's heatwave was followed by a relatively dry winter across the region.
The dry summer now could lead to serious shortages.
Today (Tuesday) the EA questioned the region's water companies about current reserves and plans of action to deal with any threat of drought conditions.
South East Water told the EA it would continue to carefully monitor water resources into the summer months and advise customers about using water wisely.
The National Farmers Union is warning of a risk to crops.
Among those concerned about climate change and the prospect of a dry summer is organic farmer Martin Hole who says: "Obviously dealing with a surplus is a worry to us. But the corresponding other half of that is longer periods of dry. We need to store water better to get us through longer periods of dry, and maybe adapt our farming systems."
One of the biggest issues for today's Environment Agency summit was the continuing scale of leakage from water companies' supply networks.
Southern Water said it had reduced leakage from its pipes by 15 million litres a day since February.
But more than 90 million litres a day continue to leak from its network enough to supply 200,000 homes.
- Watch John Ryall's report below