I installed a new kitchen sink faucet into a kitchen with over 60 year old plumbing. I tightened the connections at the point where the rigid piping meets the flexible risers, and there was some dripping, but only 10 to 20 drops per hour. I tightened them as much as I dared; any more and I fear I would have risked damaging something.
I put cups under both connections. The cold has stopped dripping (or maybe it now drips so infrequently that the water in the cup evaporates before I can look at it). The cup under the hot has only 1 or 2 teaspoons of water in it after 3 days.
Need I be worried? I live in an area with very hard water and I suppose lime deposits are flowing out and have blocked/will block the hole. The hot pipe in particular had streaks of lime all over the pipe threads; I tried to clean it but didn't get very far.
Best Answer
It is a problem, and you should fix it because small leaks tend to become bigger leaks. You can't rely on hard water deposits to seal things, and drips can cause corrosion and damage to your kitchen. Even if it stays a slow drip you'll always have it at the back of your mind. This is a case where it pays to do it right at the beginning.
It sounds like you have crud on the threads, or maybe the threads are worn. If you want to use the existing threads then clean them off thoroughly, you can use an old toothbrush to start, and a wire brush if that doesn't work. Then use teflon plumbers tape or thread sealant.
If the threads are worn or damaged you're better off cutting the pipe a bit and then either re-threading them or using a push-on or compression fitting.