UPDATE: The City of Grand Prairie says the line has been repaired Wednesday.
Because of a break in a supply line on Monday, Grand Prairie expected to run out of water Tuesday if water customers don't take immediate steps to conserve water, city officials say.
The city is asking residents to restrict water use to essential personal hygiene only through Thursday morning because of the critical situation. Water customers are ordered to turn off all outdoor irrigation systems, curtail manual outdoor watering and conserve water until the system is repaired and fully recovered.
The city originally predicted it would run out of water Tuesday but later credited conservation efforts for avoiding an outage.
City spokeswoman Amy Sprinkles said repairs to the damaged 60-inch main should be completed Wednesday. City crews will still need time to test the lines, disinfect the water and refill the water storage tanks once the repairs are finished.
"We have to fill up our storage tanks, so we have to move the water through the system to the storage tanks," said Ron McCullar, city director of public works. "If we have a lot of consumption going on, we can't get to the storage tanks; the water will be consumed before it gets there."
The damaged 60-inch line provides 28 million gallons of water daily to the city, according to McCullar. The city uses 40 million gallons of water on an average day. Another pipeline supplies the city about 17 million gallons, but won't be able to meet the full demands of the city.
"Once the water pressure goes below 20 psi, then a boil order is required," McCullar said.
The line broke after corrosion on the side of the pipeline broke through the concrete wall. Initially, crews thought heat may be responsible, but once they saw the line, they found corrosion on the pipe.
The pipeline had about three miles worth of water backed up that had to be emptied before repairs could begin.
NBC 5's Julie Fine contributed to this report.