(CNN) — Asheville, North Carolina, residents could have a boil water notice lifted as soon as Tuesday, more than seven weeks after Tropical Storm Helene struck on September 27. Helene hit western North Carolina as a tropical storm, causing devastating flood damage and harm to its water system. The storm dumped so much water over the southern Appalachians in three days that it became a catastrophic, once-in-1,000-year rainfall event for the region, the National Weather Service said. Asheville Water Resources spokesperson Clay Chandler said Friday there’s a sampling process that must take place before the notice can be lifted. “Due to reduced turbidity levels in the North Fork Reservoir and our capacity to push treated water into the system, we’ve been able to feed a sufficient amount of filtered water into the distribution system without blending it with raw water,” Chandler said. Turbidity is a measure of the level of particles in a body of water, according to the National Oceanic and Atmospheric Administration. The turbidity level must be around 1.5-2 units to be safe for a standard treatment process at North Carolina’s North Fork Reservoir, the city previously said. The North Fork Reservoir provides water to most people in Asheville, according to the Asheville Citizen-Times. Its turbidity levels dropped below 15 units on Wednesday, according to recent information released by the city. Turbidity levels had been as high as 90 units in the immediate aftermath of Helene, CNN affiliate WLOS reported. “The use of treated water combined with customer usage has given us data that we feel is sufficient to reach the conclusion that the system has, for the most part, turned over. And the vast majority of raw water has been replaced with treated water,” Chandler said. The sampling process, which was developed in conjunction with guidance from the Environmental Protection Agency and The North Carolina Department of Environmental Quality will begin Saturday, Chandler said Friday. “By Tuesday afternoon, evening, next week, we should have a pretty good idea of the health of our distribution system and whether or not we will be able to lift the boil water notice,” Chandler said. “Lifting the boil water notice will allow residents to resume normal domestic water use and for business to operate, unrestricted.” Turbidity could still increase due to unforeseen events like line breaks, or “heaven forbid,” another natural disaster, Chandler said. One Asheville couple who has lived in the area for 15 years told CNN affiliate WLOS they are excited about the possible lifting of the boil water notice. “It’s very exciting,” Corrie Enright told WLOS. “We had heard mid-December. We had been planning for another month at least.” In Buncombe County, where Asheville is located, at least 42 people died due to Helene. The Asheville City Schools district reopened last month, CNN previously reported.