The prospect of low autumn rainfall has led to talks between four water firms and West Sussex County Council.
All residents are urged to continue saving water during the autumn
Drought has tightened its grip on the whole of the South - and particularly in Kent and Sussex - after 10 consecutive months of low rainfall.
The council said shortages may continue and has urged all residents to follow latest advice on conserving supplies.
Environment Agency officers, Thames, Southern, South East and Portsmouth Water were at the talks in Chichester.
West Sussex councillor Louise Goldsmith said: "If we have insufficient rain this autumn, the shortage will continue."
The environment spokesman said: "It is important to start thinking about the implications of such a scenario and how it will impact on our residents."
The county council has now put water supply at the top of its agenda for an environment committee meeting in October.
Committee chairman councillor Martin Daws-Chew said members would be discussing climate change and the challenges that water companies would face in the light of house-building plans across the South East.
Southern Water has banned the use of hosepipes and sprinklers in its Sussex and Kent supply areas. The Sussex areas affected are Crawley, Horsham, Chichester, the area north of the South Downs, and Sussex coastal areas - areas affected in Kent are Medway and Thanet.
A hosepipe ban brought in by South East Water covers customers in East and West Sussex and west Kent, affecting 268,000 households.
The local authority areas affected are Crawley, Mid Sussex, Wealden, Eastbourne, Rother, Lewes, Tonbridge and Malling, Tunbridge Wells and Sevenoaks.
A total hosepipe and sprinkler ban is in force for all Mid Kent Water customers.
A sprinkler and unattended hosepipe ban was brought in by Sutton and East Surrey Water in April.
There are currently no hosepipe bans in the Portsmouth Water and Thames Water areas.