Man Hours 3 Items to Check & Initial Completion: 1.___ Drain, clean, and flush drinking water system. 2.___ Disassemble filters, flush and drain. 3.___ Install new gravel, sand, and charcoal. Tools & Materials: 1. Standard Tool kit. Plus Pipe wrenches to 24" Tubing cutters Flaring tool Small acetylene outfit Packing tool kit and packing 3/4" socket set Crescent wrenches to 14" 2. Respirator. 3. Gravel, sand, and charcoal.