The most recognizable sign of water damage is water. You might notice a puddle under the sink or around the toilet, or a dripping faucet. If you notice water in your home, it is important to trace its source and stop the leak, and then inspect the surrounding walls, ceilings and floors for possible damage.
Many building components, including drywall and wood flooring, readily absorb water. The water breaks down fibers, causing them to feel spongy and soft. Walk barefoot on your floors and run your hands along the walls, feeling for spots that are no longer firm. Some surfaces, such as drywall, develop a chalky texture. Peeling paint, drywall tape and wallpaper are also symptomatic of water damage.
Water and mold cause dark spots. Look for changes in the color of wall paint or carpeting. Even furniture may become discolored if the water has absorbed into the fabric. Stains may be obvious, or may appear only in cracks and crevices or inside corners.
Many types of mold cause allergies and respiratory illnesses. If you develop cold or flu symptoms that do not resolve, hidden mold might be to blame. Sneezing, coughing and watery eyes are among the most common symptoms. Some molds are more toxic than others, and can make you very sick.
The most common odor is a musty smell, but a variety of strange scents can be caused by water and mold. If you normally use air fresheners and scented cleaning products, try doing without for a full day. Sometimes you can "follow your nose" to the source of the problem.
Some leaks are imperceptible, but many are easy to detect in a quiet room. Turn off the television, radio and other noise, and listen intently. Water running through your home's walls or floors can create a dripping, scratching or even rushing sound.
Attune yourself to changes in the humidity inside your home. Difficulty maintaining a cool room temperature and trouble getting fully dry after a shower are common signs of extra humidity. Pay attention to surfaces as well. A damp countertop or wall might indicate a nearby leak.