A disaster management adviser says families in Tuvalu's capital, Funafuti, are being rationed to 40 litres of fresh water a day.
Tuvalu is entering its second week of a drought-induced state of emergency.
Desalination units from the New Zealand Red Cross are operating while work is continuing to fix some of the existing larger mobile units in the country.
Tuvalu relies almost exclusively on collected rainfall for drinking water, supplemented by a limited desalinated supply.
Noa Tokavou, who works for the Secretariat of the Pacific Community, says Tuvaluans are realising they must better prepare for similar types of disasters in the future.
Mr Tokavou says while practical steps, such as more effecient collection of rainfall is needed, there is also a need for better data on rainfall records and groundwater salinity.
According to the Secretariat ,the past 12 months are the second driest in the 78 years Funafuti has been keeping rainfall records.
They say without immediate rain, government and community water tanks on Funafuti could be emptied in less than two weeks.