Inhale deeply when you explore the confines of the apartment. Particularly in bathrooms or around the kitchen sink. Mold has a pungent, unpleasant aroma.
Examine the areas around sinks, bathtubs and plumbing for signs of mold, which may include discoloration or spotting on the ceilings over the shower or in the corners of rooms where steam may collect.
Be wary of discolored swipes on drywall ceilings or walls, which may indicate that someone has swabbed the area with bleach to remove signs of mold.
Look behind loose wallpaper or carpets, as well as under sinks and behind toilets. Mold likes to collect in dark, wet places such as these.
Monitor your health after visiting a new apartment. A sudden allergic reaction may indicate the presence of mold.
Find the apartment's history by checking newspapers or asking neighbors. If an apartment was recently flooded, it may have mold in hidden places.