What’s That Smell? The Home Inspector’s Guide to Identifying Hidden Issues

When you step into a potential new home in Calgary, Airdrie, or Cochrane, your eyes are naturally drawn to the vaulted ceilings or the modern kitchen islands. However, your nose might be picking up on the most important details of all. In the 2026 real estate market, “scent masking”—using heavy candles or plug-ins—is a common tactic. Nevertheless, a professional home inspector knows that certain odors are impossible to hide forever.

At NexLevel Inspections, we don’t just look for problems; we smell them too. Therefore, understanding what these scents signify can help you avoid a “money pit” and ensure your family’s safety. Here is our expert guide to decoding the most common (and concerning) household odors.

1. The Musty, Earthy Scent: More Than Just “Old House” Smell

To begin with, a damp or musty odor is one of the most frequent “red flags” we encounter. While many buyers dismiss this as a lack of ventilation, it often points to a deeper moisture problem. Because Calgary’s climate involves heavy snowmelt and sudden chinooks, water can easily find its way into crawlspaces or behind basement insulation.

As a result, that musty smell is frequently the first sign of active mold growth or “attic rain” issues. In fact, mold can begin to grow within 24 to 48 hours of water exposure. Consequently, if we detect this scent during an inspection, we immediately deploy thermal imaging cameras and moisture meters to pinpoint the source of the leak before it becomes a structural catastrophe.

2. The “Rotten Egg” Odor: A Multi-Threat Warning

Moving forward, a sulfurous or “rotten egg” smell is something that should never be ignored. Typically, this odor suggests one of two serious issues. First, it may indicate a natural gas leak. Since natural gas is naturally odorless, utility companies add a chemical called mercaptan to make leaks detectable. If you smell this, you should leave the premises immediately and call for professional help.

Second, this scent can originate from a “dry P-trap” or a cracked sewer vent pipe. For instance, if a guest bathroom hasn’t been used in months, the water seal in the pipe may have evaporated, allowing sewer gases to back up into the living space. Ultimately, while a dry trap is an easy fix, a cracked vent pipe inside a wall can be a costly repair that requires opening up the drywall.

3. The “Fishy” or Burning Plastic Scent: An Electrical Emergency

Furthermore, one of the most dangerous smells an inspector can encounter is a fishy or acrid, chemical odor. Interestingly, many people don’t realize that overheating electrical components—such as outlets, circuit breakers, or wire insulation—often emit a smell remarkably similar to fish or burning plastic.

This occurs because the chemicals used in modern electrical shielding release specific gases when they begin to melt. Therefore, if you notice this scent near an outlet or the electrical panel, it is a sign of a potential fire hazard. Instead of ignoring it, you need a professional to check for loose connections or overloaded circuits immediately.

4. The Sweet, Cloying Smell: Hidden Pest Issues

Finally, some odors are surprisingly pleasant but signal unpleasant guests. For example, a heavy, sweet, or “musky-sweet” scent in an attic or basement can sometimes indicate a significant pest infestation, such as mice or even bats. Moreover, if the smell is concentrated near wood structures, it could point toward certain types of wood-destroying insects. By identifying these scents early, you can save yourself thousands in professional remediation and structural repairs.

Trust Your Senses and Your Inspector

In conclusion, your nose is a powerful diagnostic tool, but it requires a professional to confirm what those scents truly mean. Instead of letting a “freshly scented” home fool you, rely on the expert eyes—and noses—at NexLevel. NexLevel Inspections is available 24/7 to provide the thorough, sensory-focused audits you need to buy with absolute peace of mind.