JACKSON, Miss. — The drinking water system in Mississippi’s capital was nearing collapse on Tuesday, severing access to safe running water for more than 150,000 people as officials scrambled to confront what they described as the “massively complicated task” of distributing bottled water and devising a plan to restore service.

The water system in Jackson, the state’s largest city, has been in crisis for years, crippled by aging and inadequate infrastructure and the lack of resources to bolster it. Residents have long contended with disruptions in service and frequent boil-water notices, including one that had already been in effect for more than a month because of cloudiness found in water samples.

The situation worsened this week as officials said that the city’s largest water treatment plant was failing. Homes and businesses were left with little to no water pressure. And officials warned that whatever did flow from faucets was not safe to consume, as it was probably untreated water that was coming straight from the city’s reservoir.