A boil-water notice in Houston made national news. In rural Texas, it’s a way of life.

On the same day that 2 million residents in the nation’s fourth-most-populous city faced a boil-water notice that garnered national attention, a water system near this tiny East Texas town issued similar warnings to customers, marking the 68th boil-water notice issued this calendar year.

And while Houstonians responded to the news by scrambling to stock up on bottled water, customers of the Consolidated Water Supply Corp. proceeded as usual.

“We’ve had problems with the water since we’ve been here,” said David Wilshusen, a 69-year-old retired construction worker who has lived in an...