Aid workers say around 1.5 million Mosul residents will be left without water, electricity, food and medicine as the offensive to retake the city intensifies.
The water supply across a large part of Mosul has been cut off as fighting intensifies between Iraqi forces and Daesh, making it even harder for families caught in the crossfire to find basic supplies.
More than 650,000 people who have been left without water after a pipeline was hit by shelling, "are facing a humanitarian catastrophe," according to Mosul's Nineveh provincial council member, Hussam al-Abar.
"About 1.5 million people were still inside Mosul and basic amenities such as water, electricity, medicine and food are hard to find or are very expensive."
According to aid workers, more and more civilians will suffer as the offensive to retake Mosul in its sixth week.
"Key informants are telling us that poor families are struggling to put sufficient food on their tables," UN Humanitarian Coordinator in Iraq, Lise Grande said.
The Mosul operation has been ongoing for six weeks after the Iraqi government resolved to regain its writ in the city which has been under Daesh control for two years.
Iraqi forces, Kurdish peshmerga fighters and Popular Mobilisation Forces backed by an international coalition are participating in the operation, which is facing serious resistance from Daesh.
Iraqi forces moving from the east have captured about a quarter of Mosul, trying to advance to the Tigris river that runs through its center.
"In a worst case, we envision that families who are already in trouble in Mosul will find themselves in even more acute need." Grande said.
"The longer it takes to liberate Mosul, the harder conditions become for families."
A spokesman of the coalition, US Airforce Col. John Dorrian, said there was "a sense of urgency" to capture the city, without giving a target time frame.
"The Iraqis will do it at a pace and a tempo that will enable them to protect civilians," he said.
At the same time, Daesh is cracking down on people who are colluding with Iraqi forces.
"Daesh is still there," said Ehab, a high school student, "They drive around in cars; the situation is very, very difficult there. I am glad I made it out alive."