"Water is one of the most acute needs of children and adults in eastern Ukraine," Giovanna Barberis, UNICEF representative to Ukraine, said in a statement.
With little rain in recent weeks and soaring summer temperatures, conditions are becoming increasingly difficult for residents. In Mariupol, a city of 500,000 in the Donetsk region, they rely on water from a "rapidly depleting" reservoir, UNICEF said.
According to the agency, only 60% of the pre-conflict water supply capacities are still functioning, forcing many families to rely on water trucks or travel with buckets to neighboring villages that still have working wells.
To make matters worse, the risk of waterborne disease is likely to increase as people are unable to store or transport water safely.
"No children and families should have to risk their lives in order to access one of life's basic necessities for survival," Barberis said.
Since January, UNICEF has helped more than 550,000 people in eastern Ukraine access safe water. The agency said more humanitarian partners are still needed for the water and sanitation response.
Nearly 1.4 million people have been displaced within Ukraine since the conflict began in March 2014. More than five million people are in need of humanitarian assistance, including 1.7 million children, UNICEF said.
The agency said it has received only 19% of the $55.8 million it requested to meet urgent humanitarian needs of children and families in the region this year.
