The Tyngsboro Wellfield (TWF) was shut down yesterday (7/19) to allow the contractor to make a connection between the existing 12” and the new 16” water mains. The picture shows the cross section of the existing 12” water main. There is ~1” of buildup around the inlet of the pipe. The buildup is the minerals from the water. The TWF’s well water contains Iron and Manganese. The buildups will be disturbed and peel off when the flow changes direction (such as caused by shutdown, flushing hydrants or water breaks), thus causing the “brown water”. District staffs have been flushing the water mains at Tyngsboro area in order to improve the brown water from the water main yesterday (7/19) afternoon and evening. We will continue the flushing in the area this morning. However, it will take some time to allow the water to become clear. Please note the existing 12” water mains were installed in 1951. The District is trying to improve the system by replacing these old water mains. There will be temporary inconveniences (such as brown water) for some of the residents. However, the water quality will improve once the old water mains have been replaced.