How do I find a water leak in my house?

Start with the water meter. The EPA says to check it before and after a two-hour period when no water is being used. If the meter moves at all, you probably have a leak somewhere in the house.

Then narrow it down by checking the common leak spots: toilets, dripping faucets, and pipe fittings. A few drops of food coloring in the toilet tank is a simple test; color in the bowl after about 10 minutes means the flapper is leaking. The EPA also notes that a family of four using more than about 12,000 gallons in a colder month can be a sign of a serious leak.

If you find a steady drip or wet joint, fix that first. Faucet washers, gaskets, and toilet flappers are the usual small parts that fail, and they are often cheaper to replace than the whole fixture.