Picton and Waikawa residents are being asked to urgently conserve water - to avoid running out of it completely.
From Friday, a total hosing ban will be in in place - with no boat washing permitted at launching ramps in the town and no car washing allowed either.
The Marlborough District Council will also limit its irrigation of Endeavour Park and shut down the water fountain on the Picton Foreshore.
Council operations and maintenance engineer Stephen Rooney said the restrictions introduced on Tuesday that required residents to limit their sprinkler use to alternate days had made a small impact - but had not been as effective as hoped.
"We are now asking locals to do more to save water immediately. Don't use sprinklers or the garden hose, take a short shower, turn off the tap when you are brushing your teeth and don't wash your car.
"Every single action will help us avoid a loss of supply."
He said the largest water use in Picton and Waikawa is on gardens, at marinas and the irrigation of large open spaces. The Foreshore fountain also uses a significant amount of water each day.
Water recently stopped flowing over the Essons Valley dam due to low rainfall and high demand, with the township now reliant on the Speeds Road supply and the reservoirs at the Elevation and Victoria Domain.
"Speeds Road cannot keep up with Picton's water usage which means, without rain, we are slowly losing water from the reservoirs.
"This cannot continue as we need to keep adequate levels in the reservoirs to cater for short outages at Speeds Road and for firefighting purposes."
Rooney said if storage capacity was restored over the weekend, the restrictions may be eased.
The water restrictions have been discussed with cruise industry representatives to make them aware of the issues the town is currently facing.