The Marshall Islands Environment Protection Authority is advising residents to boil their water or purify their own watertanks.
The Authority says the public water system has signs of contamination from a lack of water pressure as rationing of water tightens due to a long dry season.
The manager of EPA's Water Quality Management, Abraham Hicking, says as a result, they found traces of e-coli in the water, but they are working to fix the problem.
"We advise continually to boil water. And if they cleanup their rain water tank with it, they add chlorine to it . We advise them to add one cup of bleach to one thousand gallons of water. Let it sit overnight before the next day to drink."
Majuro Water and Sewer Company reduced city water hours from three to two days a week last month.
Mr Hicking says this could be reduced even further due to the ongoing water shortage caused by insufficient rain.