The answer to 'how to unclog water line replacement' is to first identify and isolate the clogged section of the water line. This may involve turning off the main water supply and draining the line. Next, use a plumber's snake or auger to try to break up and remove the clog. If that doesn't work, you may need to replace the affected section of the water line.
Be sure to take safety precautions like shutting off the water supply, wearing gloves, and working slowly and carefully. Unclogging a water line can be a complex task, so consider calling a professional plumber if you're not comfortable doing it yourself.