Subscribe to The Y'all -- a weekly dispatch about the people, places and policies defining Texas, produced by Texas Tribune journalists living in communities across the state.

McALLEN -- Laredo is entering its sixth day of a citywide water boil notice after traces of E. coli were discovered in its public water system.

Now officials in this South Texas city are scrambling to repair old water pipes that could have been at the center of the crisis.

While the underlying cause remains unclear, Mayor Victor Treviño said Tuesday an investigation done in coordination with the Texas Commission on Environmental Quality narrowed the potential source of the contamination to an area in central Laredo. Outdated infrastructure is a likely factor, he said.

"Unfortunately, the same investigation shows that the overall problem is multiple years in the making and we are now playing catch up to a problem that has grown to what it is today," Treviño said during a press conference Tuesday.

Laredo is the latest Texas city to grapple with outdated water infrastructure and it is one of the most populous cities to issue a boil-water notice since Houston did about two years ago. More than 256,000 people live in Laredo, a border town about 160 miles southwest of San Antonio.

Earlier this year, the West Texas city of Odessa had to shut its entire water system off to upgrade its water infrastructure. In 2023, state lawmakers and voters created a new pool of money to help the state repair some of its water pipes.

As of Tuesday afternoon, the entire city remained on a water boil notice issued by the city on Thursday after follow-up water tests on Sunday identified two positive E. Coli results in central Laredo. Another sample detected high bacteria levels on the city's north side.

Treviño said he would be meeting with TCEQ again and planned to call an emergency meeting of the City Council in the coming days to take emergency action.

The mayor wants the City Council to divert all available resources to deal with the water crisis, requesting that all non-essential projects be paused or eliminated so that funds could be diverted to replace outdated water pipes.

"About 40% of the pipes are over their shelf life so that is something to look into," Treviño said in an interview with the Texas Tribune.

He also plans to ask the council to issue discounts to residents on their water bills and for the appointment of an interim executive director to head the city's utilities department beginning Oct. 21. Laredo City Manager Joseph Neeb currently oversees the utilities department.

The interim executive director would also serve as a performance consultant, Neeb said, explaining the department has been shorthanded on engineers, relying on outside firms to help them.

Faced with the water crisis, Neeb said the city hoped to find a long-term solution, noting the city had budgeted more than $100 million for water and sewer repairs this year.

"We will be talking about adjusting our plans from what we thought they should be to what they really need to be," Neeb said during the press conference.

Meanwhile, the city will continue to hold water distribution sites while the notice remains in effect. Treviño hopes that by identifying the affected areas, the city can begin to rescind the notice for unaffected areas of the city.

Under the notice, residents are warned that tap water is not safe for drinking, cooking, or brushing their teeth. However, it can be used for other consumption if boiled for one minute.

No resident has tested positive for E. coli from drinking the city's water, officials said. However, they are investigating all reports of illness.