Workers With The Johnson City Water And Sewer Service Department Will Be Smoke Testing Sanitary Sewer Lines In The Knob Creek Wastewater Treatment Plant Collection System. Smoke Testing Helps The City Determine Points Where Extra Water Can Enter The System. If Smoke Enters Your Home During This Testing, There Are Deficiencies In Your Plumbing And You Should Call 423-461-1645. The Testing Is Expected To Last Through Mid-November.