Leak Under Sink

"Hey, there is water leaking under here!" That's what my wife said yesterday as she was cleaning under the sink. Oh, how I don't like plumbing problems! But where exactly is the leak coming from? That's always the first thing you need to look for is the origination of the leak. I emptied the under-sink cabinet, turned on the flashlight and went on a leak hunt. At first glance I noticed that the black drain pipe was dripping. Thinking that there was a leak in the drain I filled up the sink then let it drain, sure enough there was water dripping off the drain pipe that connects the two sink drains. Great! I think, "I'm going to have to take this whole pipe off and repair it somehow." I was not looking forward to that. Here is the under-sink view:

But notice the two white water supply tubes zip-tied to the black drain pipe. I thought, "Hmm what if one of the water supply tubes is leaking - they are touching each other." So, I plugged up the sink because if there is no flow through the drain pipe a leak would not show up until I pulled the plug. Sure enough, even though I had the sink plugged the pipe appeared to be leaking. Therefore it was not the drain pipes. Indeed! The culprit is here:
As it turns out the water supply tube was leaking where it screws into the faucet nipple. All I had to do to fix the problem was to re-tighten the nut (hand tight). I am assuming that after two years of the near earthquake conditions of travel this fitting jiggled loose. (Is jiggled a word?) So, for my fellow travelers, it may be a good idea to check the "tightness" of your water supply fittings every year or so just to be sure no leaks develop. Jim