For almost 30 years Perman Hardy obeyed a simple rule: When it rains, turn off the water. 

Ms. Hardy had a failing septic system, and precipitation meant wastewater flowing from her house wouldn’t be treated and released into the soil. More likely, it would flow back into her home. So until the last raindrop fell, she halted everything involving a sink, shower, toilet, or washing machine. 

Still, Ms. Hardy considers herself fortunate. For one, in her hometown in Lowndes County, Alabama – one of the state’s poorest and most rural – many people don’t have access to sewage treatment at all. For another, as of this summer, Ms. Hardy no longer has to follow her rule.