Police and municipality chiefs are investigating the cause of a major water contamination in a cluster of towers in Ajman.
Scores of people were taken to hospital at the weekend after using the supply in Horizon Towers in the emirate.
Men, women and children reported feeling unwell after using tap water for washing, cooking and cleaning.
Many then developed high temperatures, started vomiting and suffered intestinal complications.
A figure for how many fell sick has not been confirmed but it is thought to be more than a 100. Most have now been released but seven remain in hospital where it is believed they are in a stable condition.
Some residents have now even been forced to stay in hotels or with friends until the issue is resolved.
Municipality chiefs said the water tank supplying the building had been contaminated and an investigation was underway into the cause of the problem. Tankers could be seen at the site on Sunday.
"Samples were taken and sent to laboratories to determine the cause of pollution in coordination with the tower management," Ajman Police said.
"All the ground and upper tanks have been emptied, cleaned and sterilised. The final results will appear during the week," it said.
It is believed the tanks will be refilled once the all-clear has been given.
Signs posted by the building's management on Sunday also instructed residents not to use the water because of an "emergency".
Residents had earlier complained of a bad smell in their apartments.
