HAYNEVILLE, Ala. — What babbles behind Marilyn Rudolph’s house in the rural countryside is no brook.

A stained PVC pipe juts out of the ground 30 feet behind her modest, well-maintained house, spewing raw wastewater whenever someone flushes the toilet or runs the washing machine. It is what is known as a “straight pipe” — a rudimentary, unsanitary and notorious homemade sewage system used by thousands of poor people in rural Alabama, most of them Black, who cannot afford a basic septic tank that will work in the region’s dense soil.

“I’ve never seen anything like it. It’s kind of like living with an outhouse, and I can never, ever get used to it,” said Ms. Rudolph’s boyfriend Lee Thomas, who moved in with her three years ago from Cleveland.

“I’ve lived with it all my life,” said Ms. Rudolph, 60.