Guilford County is asking certain homeowners for permission to test their well water for so-called forever chemicals, also known as PFAS. The county has contacted about 100 homeowners who live along Brush Creek and Horsepen Creek near the Piedmont Triad International Airport, asking them to participate in the sampling effort. Joe Johnson, with the county’s division of environmental health, says it’s too soon to say how officials will respond if high PFAS levels are found in homeowners' water.