Added to a lack of electricity - the national grid is off more than it is on - a crumbling mobile phone network, endless lines to get fuel and a daily dose of bombs and mortars, it has made it next to impossible to even think about the coming election.
"This is everyone's biggest problem," according to Alaa al-Din Saad, 32, a father of two who lives in the southwest district of Saidiya.
"We haven't had water for nearly a week. We used up all our reserves and now I haven't had a shower for three days."
Iraq's national election, just seven days away and expected to bring its own set of problems amid fears of a surge in violence, has taken a back seat to the need to find a water source in a country that is mostly desert but also has two of the world's major rivers.
There has been no explanation for the crisis, which has provoked such anger and frustration that one Iraqi called a news agency demanding that something be done.
Fighters are suspected of attacking water mains outside the city several days ago, cutting off supplies, but the US military had no immediate information on such an attack.
Iraq's national elections will take
place on 30 January
In the absence of hard information, rumour and speculation often run riot in Iraq.
Some Baghdad residents say the Iraqi government and US military have cut off the water on purpose to frustrate people and prompt them to vote in the 30 January election.
Others take the water shortage as yet another sign that the US invasion has brought them nothing but problems.
"Nothing works - there's no power, no water, no fuel, no phone service. It's a disaster," according to Namidh, a security guard who said his family had been without water for a week.
A spokesman for the public works ministry had no explanation for the crisis and referred callers to the mayor's office. No one was available at Baghdad city hall during the Muslim religious holiday of Eid al-Adha.
"We haven't had water for nearly a week. We used up all our reserves and now I haven't had a shower for three days"
Alaa al-Din Saad,
In some areas there is absolutely no water; in others, there is a trickle for a few hours a day.
The crisis has left many families unable to cook, wash clothes or bathe.
Some have taken to digging wells in the back garden in the hope of striking water. Those who get lucky are now supplying the neighbourhood. "People are lined up all day to get water from our well," Badia Yasin, a driver, said.
A police source said about 300 people were taken to the hospital in west Baghdad this week with stomach problems and similar ailments and complaining of having been poisoned.
But officials at al-Yarmuk hospital, one of Baghdad's main clinics, said they had had no major increase in patients suffering from water-borne diseases such as cholera. Other hospitals were not immediately contactable for comment.
A health ministry official played down fears of a cholera outbreak but said disease could rise if the water crisis is not resolved soon. "There will be health problems if we don't sort this out," he said.