How-to site wikiHow has a great tip for locating a water leak in your home before calling in the plumber: Use a screwdriver as a crude stethoscope to locate your leak.
Photo by a.drian.
If you suspect something's amiss in your plumbing, you'll need to locate a hose-bib. In case you don't know, a hose-bibs are the pipes that you hook your hoses to. WikiHow explains that:
Once you have located [a hose-bib] , take a screwdriver, preferably one long enough to give yourself room to work, and put the metal tip of the screwdriver directly on the metal part of the hose-bib. Put your thumb knuckle on the top of the screwdriver, and then place your knuckle on the side of your head, immediately in front of your ear. The sound will travel directly to your ear drum. The idea, here, is for the solid screwdriver to work like a stethoscope. This works for most metal valves, as well.
Clever! Once you find your leak, there's still the matter of fixing it, but the screwdriver-as-stethoscope idea is one you may be able to put to use in a pinch. And while we're on the subject of leak-hunting, don't forget how effective food colouring is in diagnosing a leak.