Paul Naragliano, 74, said Monday he and other patients were transported to another area of the ER at Surrey Memorial Hospital when water started spilling in.
"But the water, after one hour or so, was coming there too. So the nurses were all running around with rags and tried to stop the water and they asked us to go one floor up and we went up."
Naragliano said he saw about 10 centimetres of water on the floor when patients were being transported out.
"I can walk, and I know what's going on, but some patients needed help," said Naragliano, who was wearing an oxygen mask as he was hurried out of the ER.
Tasleem Juma of the Fraser Health Authority said a construction accident caused the water main to break, creating significant damage to the ER.
Juma said 25 patients were in the ER at the time of the incident, just before 9 a.m., and they have been relocated to other areas in the hospital.
"My understanding is that at the peak of the water coming in, we were looking at about ankle-height water."
She said the diagnostic imaging area is also damaged from the water, which was originally considered contaminated but by later in the day, was concluded to simply be dirty.
The ER will remain closed for "at least several days," as officials develop a restoration plan, announced the health authority in a statement Monday evening.
All new emergency patients will be sent to an outpatient clinic and surgery area.
The health authority said while one operating room is now functioning for emergency surgeries, a total of 108 elective, non-urgent surgeries have been postponed.
Patients requiring dialysis will be directed to other facilities Tuesday because the hospital's renal unit will remain closed for outpatient services.
Motorists are being told to stay away from the area because several blocks around the hospital are closed.
The health authority said it does not yet know how much the incident will cost.