Officials in Tuvalu say they do not expect there to be any let-up in the dry conditions which led to an emergency declaration last month, when there was only a few days of drinking water left.
New Zealand and other countries have sent aid to help cope with the drought.
A desalination unit set up by the defence force on Monday has helped replenish water supplies for residents and hospitals, but households are limited to a ration of 40 litres a day, regardless of the number of inhabitants.
While the immediate relief has served as a buffer, the current commitment is due to finish in less than four weeks.
Tuvalu officials are hoping for further assistance as the weather is expected to remain dry until January.
