When you walk into a home, your nose often picks up on what your eyes can’t see. During inspections, I’ve learned that certain odors can be early—and sometimes urgent—signals that something within the home needs attention. While it’s easy to dismiss a smell as “just musty” or “probably the pets,” odors can offer critical clues about hidden issues affecting indoor air quality and structural integrity.
Let’s break down some of the most common smells and what they might be trying to tell us.
1. Musty or Earthy Odors
This is one of the most common red flags. A damp, basement-like smell is often linked to mold or mildew. Mold thrives in moist, poorly ventilated areas—crawlspaces, behind walls, or under flooring. Even if mold isn’t visible, the presence of this odor means it’s time to investigate further. Moisture intrusion from a leak or inadequate ventilation could be creating ideal conditions for microbial growth.
2. Rotten Egg Smell
A sulfur-like or rotten egg odor is never something to ignore. It may indicate a natural gas leak, particularly if the smell is strong near appliances or in closed-off areas. Another potential source is sewer gas, which can enter the home through dry drain traps or faulty plumbing. Either scenario warrants immediate action—both for health and safety.
3. Pet or Ammonia-like Smells
Strong urine or ammonia odors, often attributed to pets, can sometimes indicate more serious problems. Prolonged moisture exposure in flooring (especially with past pet accidents) can lead to bacterial growth or even mold beneath carpeting or subfloors. It’s also worth checking for signs of rodent infestations, especially in attics or crawlspaces.
4. Smoke or Stale Cigarette Odors
Tobacco smoke residue is more than just a cosmetic concern. Third-hand smoke can cling to walls, ceilings, and HVAC systems, impacting indoor air quality long after the last cigarette. It may also mask other underlying odors or damage from previous fires.
5. Sweet or Chemical Odors
Unusual sweet or chemical smells can sometimes point to volatile organic compounds (VOCs) off-gassing from new materials like carpets, paint, or laminate flooring. While not always dangerous, poor ventilation can make these odors linger and may impact sensitive individuals.
Trust Your Nose—and the Inspection Process
If you walk into a house and something doesn’t smell right, there’s likely a reason. Smells offer more than discomfort—they’re often the home’s first warning sign. Paying attention to them during an inspection can lead to early detection of moisture problems, contamination, or environmental concerns that otherwise go unnoticed.
In short, when it comes to a home’s health, the nose really does know.