Hosepipe bans could be slapped on at least 17 million Britons who would risk £1,000 fines if they were caught flouting the restriction.
Almost a million people across Hampshire and the Isle of Wight who are supplied by Southern Water are subject to the ban, which will come into effect on Friday, after severely below average rainfall over the last eight months in what has so far been one of the driest years on record.
The dry weather is causing other companies such as Thames Water, South East Water and Welsh Water to also consider bans and they are calling on their combined 17.3 million customers to cut back on how much they use.