Hauntings by definition are a collection of unexplained paranormal activity clustered in one spot---e.g., your house. Investigate the possible source of any mysterious noises before calling in a medium. Settling floorboards are the usual culprits of "eerie footsteps," and old pipes can make quite a racket in the walls. Once you think you have a haunting, the power of suggestion can play tricks on your mind. If you've exhausted all logical solutions, though, consider the symptoms of what could be a legitimate haunting.

Ghosts

Though spotting a ghost is the most obvious sign of a haunted house, rationalize and think about what you've seen before jumping to that conclusion. Ghosts reportedly appear as solid people; only on TV and movies do ghosts appear as ethereal, transparent wisps. Similarly, the idea of ghosts turning up in period clothing seems to be a 20th century idea. People who claim to have spotted them have asserted that ghosts tend ignore their witnesses, but your "apparition" could also be a deaf, blind or just distracted person. The ability to perform the impossible---walking through walls, vanishing from sight---represents an obvious clues, but, again, make sure it you didn't see an optical illusion. If your ghost can hold up against several logical explanations, it might be legitimate.

Subtle Signs

Hauntings often take more subtle forms than ghosts. Listen for unusual sounds, such as whispering, laughter, screams and talking that you cannot explain. Some witnesses have reported strange or out-of-place odors, such as perfume or cigarette smoke. Watch for doors to open, furniture to move, and picture frames and other objects to fall off the wall and tables. Lights and televisions may also turn on unexpectedly. Search for unexplainable cold spots; people also report being touched by unseen fingers. Try capturing the unseen using an electronic voice phenomena, reportedly tunes into a special frequency to attempt to capture the voices of ghosts.

Reactions of Visitors

Notice the reaction of visitors to your home---especially small children and pets. Residents in a haunted home become immune to its effects over time, but first-time visitors will often feel the energy in the house. Listen to what children say or point to while in your house; they often exhibit more sensitivity to paranormal phenomena than adults. Dogs will bark or growl for no reason or stare at the air as if someone is standing there. Make a note of where in the house visitors and animals sense the phenomena. Multiple visitors independently confirmed it, you may have a haunting.

Source:

ASSAP: How Do You Know If You've Seen a Ghost

Ghost Haunts: How To Know When Your House is Haunted

ASSAP: Symptoms of a Typical Haunting