The Pacific Islands Applied Geoscience Commission, or SOPAC, is calling for action to address the water shortage of many urban Marshall Islanders.
The government's water company is pumping rain- and ground water to urban homes twice a week and households must collect rainwater in private tanks.
But the preliminary finding of a study looking at water access in the capital Majuro shows about a quarter of those surveyed don't have access to water in their homes.
SOPAC's water adviser, Marc Overmars, says a number of areas need to be improved.
"On Majuro, there's a dilapidated system in place of the water supply that needs to be upgraded. It's expected that the losses through the system are increasing fifty percent, which is something that urgently needs to be addressed. In compensation, people are now increasing their personal rainwater harvest storage and that needs to be increased."
Marc Overmars says increasing access to piped water is also crucial.