Flexible Plumbing Supply Lines
Two basic types of flexible supply lines are available – tubing or braided hoses. Plain and corrugated copper tubing and plastic tubing require ferrules and nuts for connections to the stop valve.The fixture end differs for faucets or toilets. Braided flexible supply lines – either plastic or stainless steel – have attached nuts (different for faucets or toilets) at one end and nuts for stop valves at the other. Braided lines are the easiest to use. Make sure you buy lines of an appropriate length. Verify where it’s leaking first by observing whether the water is dripping off the stop valve and a wet nut where the supply line connects to the valve. That could be a loose connection.
Try this solution:
Tip #1 Tighten the Nut
Often the solution is as simple as tightening the nut at the point where you see a leak. Take care not to over-tighten – you can crack the nut or strip the threads. Use only adjustable wrenches, not pipe wrenches. If the leak persists, loosen the nuts and re-coat the threads or ferrules with plumber’s tape or pipe joint compound.
Tip #2 Shut Off the Water and Drain the Line
If you are working with a tubing-and-ferrule connection, remove the nut and pull the line out of the valve. Take care not to kink it. Wrap the ferrule with plumber’s joint tape or coat it with joint compound. Hook it back up, tighten, and test.
If these measures fail to solve your problem quickly, it could be the fault of the old line. Buy a new flexible line, apply joint tape or joint compound to the male threads, and screw it on. Tighten both ends and test.
I loved reading that your top solution for preventing a leak is to simply tighten the nut at the point where you see the leak appearing. I would imagine that a simple fix like that would be achievable by even the most inexperienced of homeowners. That being said, I am sure that finding a good plumbing supply store before trying to do any work would still be a good idea, in case something does go wrong along the way.