§ What happened
A backflow preventer at a single Laredo home failed, permitting contaminated water to enter the distribution system.
City crews isolated the property, removed the meter, and began cleanup and sampling.
Officials collected 50 samples on two occasions over three days to confirm water safety.
The boil water notice remained in effect for four days until testing cleared the system.
Why it matters
Even a single failed residential backflow preventer can trigger a multi-day system-wide advisory, showing how quickly localized failures affect public water quality.
◇ Prevention lesson
Property owners must maintain backflow preventers on their side of the meter; the city can only protect the main distribution network.