Somewhat like Brigadoon, the village of Broadway musical fame that reemerges for a short time every century or so, you have to drive down a misty road off the main highway to reach the once-idyllic town of Saint Joseph.

Isolated along the Mississippi River in northeast Louisiana, quaint antebellum homes line a market green that was built in 1843. Before last month’s discovery that nearly a quarter of the town had tap water laced with unsafe levels of lead, the last time St. Joseph was noticed was when Ulysses S. Grant crossed the river on his way to capturing Vicksburg.

This reemergence, however, brings an ominous warning of yet another long-ignored expense for Louisiana taxpayers.

St. Joseph’s water has run brownish out of the tap for years, as it has in as many as 400 Louisiana towns, raising all sorts of safety concerns. All these towns are small, impoverished, predominantly minority, and can’t afford to maintain the infrastructure needed to deliver water, safe and pure.

The only difference with these other towns is that St. Joseph has attracted more attention, the former four-term mayor, Edward Brown, said on his last day in office.

Since the December tests discovered lead, state taxpayers are giving every person in St. Joseph three liters of water per day and an $8 million makeover for the 90-year-old water system.

Cecile Evans recalls that a generation ago her hometown was where farmers came on Saturday do some shopping and catch a movie. Nowadays, the theater is gone and much of the main street is pock-marked with boarded-up shops.

The standard of living took a nose dive when farming became corporate and mechanized. St. Joseph’s median household income in 2015 was $16,923 as compared to $54,774 in Baton Rouge and $51,939 nationwide, according to the Census Bureau.

Without a tax base, towns like St. Joseph routinely delay spending on maintenance, a practice that is now coming back to haunt them, says Lady Carlson, a Together Louisiana advocate who helped bring St. Joseph’s plight to the Legislature’s attention and now is focusing on the water problems in the other forgotten communities.

“We have trouble getting people from Baton Rouge and New Orleans to go to places like Lake Providence. It’s too far away. It’s in the hinterlands. So they just get ignored,” Carlson said. Together Louisiana, a coalition of clergy and community groups, entered the fray last year at the request of the Episcopal Church.

Archdeacon Bette J. Kauffman, of the Episcopal Diocese of Western Louisiana, had been driving down from Monroe over the years to officiate at the 160-year-old church, which now only attracts 20 or so parishioners each Sunday. She started sending young volunteers to work in the town.

And that’s where the matter would have stayed if one of Kaufman’s volunteers hadn’t lost his temper a year ago this week. Wanting a morning shower, a bleary-eyed Garrett Boyte turned the tap on in the 175-year-old rectory and only a rusty mud came out.

Boyte was told the water was safe — manganese and iron caused the discoloration. “You see what it does to the bathtub and you know you don’t want to put that in your body,” he said.

An Oak Grove native who is studying for the priesthood at the University of the South in Sewanee, Tenn., Boyte posted a video of muddy-water that got picked up by the “NowThis” social media news platform.

This all happened as the Flint water crisis came to a head. In Michigan, the jugs of discolored water from aging pipes evolved into lead readings and an emergency declaration by President Barack Obama in January 2016. Boyte’s images went viral.

But St. Joseph’s problem is not isolated. Doing the math on his fingers, Boyte last calculated that repairing the infrastructure will cost taxpayers about $2.4 billion if one accepts that 300 other Louisiana towns — the low end of the estimate — need similar repairs.

“People are not going to send their hard-earned money to some Podunk town they’ve never heard of before,” Boyte said. “That worries me.”

Jan Moller, head of the Louisiana Budget Project, sees little choice.

Years and years of “deferred maintenance” have left Louisiana public colleges needing $1.6 billion in repairs, while highways and bridges need another $12.7 billion to catch up.

But this problem trumps them all.

“It’s one thing if it’s a library needing a coat of paint. It’s quite another if the water is not safe,” Moller said. “There’s probably no greater obligation of government than to make to make sure children are not poisoned by drinking the water.”

Follow Mark Ballard on Twitter, @MarkBallardCnb.