The sound of dripping water inside your home on a rainy evening is enough to make your heart sin, but a leaky roof doesn't always announce itself so clearly. Periodically checking for signs of moisture intrusion will let you identify a potential problem before it requires a costly repair.

Water stains are perhaps the most obvious sign that a leak has developed in your roof. The home sustainability resource Modernize.com says these will appear as brown, gray, or yellow marks on your ceiling or walls. These stains are a sign of advanced water damage, so if you spot them you should immediately start looking for the source of the problem. Smaller leaks won't produce water stains, but will still allow enough moisture into the home for mold to form.

Get into the habit of regularly inspecting your roof to see if there are any troublesome spots. If you're wary about climbing to the top of your home to scrutinize the shingles, use a pair of binoculars to safely get a closer look from the ground.

If the shingles have been damaged or compromised, they are much more likely to allow water in during a storm. The home improvement site HomeAdvisor says you should look for shingles that are missing, torn, or curled. Weakened shingles not only offer less water protection, but are also more likely to be torn off by strong winds.

Check for the formation of algae or mold, which can also weaken the shingles. SonShine Roofing, a company in Sarasota, Fla., says this problem is most likely to occur in warm, humid weather conditions.

Some of the granules on asphalt shingles will naturally be shed over time, but the majority should remain attached. If you start noticing a large number of granules in your gutters or see that the shingles are largely barren, they will probably need to be replaced.

Roofs will have openings for features such as vents, chimneys, and skylights, and water can make its way into the home if the opening is not properly sealed. During your inspection, look for flashing or caulk that is cracked, rusted, or warped. The magazine Family Handyman says you can also look for small openings, such as nail holes left behind from an antenna or satellite dish which was formerly on the roof.

If your home has an attic, you can get a close look at the underside of the roof, which may provide some additional warning signs. SonShine Roofing says water stains may be visible on the attic ceiling. Modernize.com says there may be a damp or moldy smell, although this could also be a result of insufficient ventilation.

For flat roofs, look for blisters or wrinkles in the membrane. These blemishes are a result of water making its way beneath the roof layer, then expanding as the roof heats up. Crown Industrial Roofing of Toronto, Canada, says you may also notice pooling water or exterior damage near the roof such as peeling paint.

If the roof seems to be in good condition, make sure the leak isn't coming from another source, such as a radiator pipe. Family Handyman says protruding nails in the attic are often the culprit when you notice a small leak. Condensation forming on these nails can freeze during cold weather, then drip away when thawed. Clipping these nails to be flush with the attic ceiling can resolve the issue.

Finding a leak in the roof can be tricky, since water entering in one location can often flow to another point before entering the home. Staining in the attic is the most obvious clue for a leak's location, but you may also need to carefully check the areas above where the water is entering.

Simulating a rainstorm can be particularly effective in finding a leak. Enlist a helper to direct water from the hose onto the roof, letting it run on a spot for a few minutes before moving on to another area. Once you notice water starting to drip into the home, shut off the water and make a note of the problem spot.

Determine what an appropriate repair for the leak should be. Some fixes can be fairly simple, such as replacing damaged flashing. If the problem is more widespread, such as a roof full of worn-out shingles, you may need to consider adding another layer to the roof or replacing it entirely.