Thames Water have warned that the hosepipe ban that starts today could last until next Autumn.
Richard Aylard told BBC Radio 4:
"Realistically I think it will be in place throughout the summer and into the autumn unless we have an unusually wet year."
"This situation has taken a couple of years to build up, it will take quite a long time to put right."
Millions of homeowners have been banned from using hosepipes from today as drought grips parts of the country.
Deep underground, the drying-up boreholes of East Sussex show the extent of the UK's drought problem.
20 million people across the south and east of England will be hit by hosepipe bans that have come into effect since midnight.