Representatives of the Government, the water industry and agricultural groups met on Tuesday for new emergency talks to discuss the response to possible drought conditions across the country.
Most of England is now in a prolonged dry spell, after the driest July since records began.
Southern has asked customers to “gently remind” their neighbours, family or friends if they are seen ignoring the ban on using hoses or water features in Hampshire and the Isle of Wight.
He said he would initially speak to anyone reported at the company, but warned they could face a fine of up to £1,000. The company is understood to rely on reports from the public to enforce the rules.
South East Water was among the first to warn of shortages during last month’s heatwave, moving Kent into red state for water as warm temperatures contributed to the rise of the demand.
Thames and South West told The Telegraph they may have to introduce restrictions in the coming weeks. Others in the south, including Portsmouth and Wessex, said they were not currently considering any restrictions.