Work from strongest to weakest

Do this when the house has been closed for a few hours, so odors have a chance to build.

  1. Walk the house with fresh senses

    Start from outdoors or a room you know is fine, then move through each level and note where the smell is strongest.

  2. Open closed spaces

    Sniff inside closets, sink cabinets, mechanical rooms, under-stair storage and built-in cabinets as you open them.

  3. Check the low points

    Basement corners, behind furniture on exterior walls and carpet edges near foundation walls are frequent sources.

  4. Follow the water

    Note every room with plumbing, appliances, windows or roof edges above it; overlap with odor is a strong lead.

  5. Write it down

    A quick floor sketch with odor notes is useful to the person doing a professional inspection.

Where the smell is, and the usual suspects

Strongest odor location
Closet on an exterior wall
Commonly found source
Condensation in the wall or a leak at a window above
Strongest odor location
Finished basement room
Commonly found source
Seepage at the foundation, wet carpet pad, plumbing in the slab or walls
Strongest odor location
Near a bathroom
Commonly found source
Leaking toilet seal, shower pan or supply line inside the wall
Strongest odor location
Mechanical room
Commonly found source
Condensate drain, water heater or humidifier leak
Strongest odor location
Whole house when the HVAC runs
Commonly found source
Growth in a coil, drain pan or duct, or a source near a return
Strongest odor location
Kitchen
Commonly found source
Dishwasher, refrigerator ice maker line or sink drain

What a professional inspection adds

Moisture meters can find wet drywall and wood without cutting anything. Thermal cameras show temperature differences that often line up with damp areas, though a thermal image is a clue rather than proof of moisture. Hygrometers measure humidity room by room. Together, these tools usually narrow a hidden source to a specific wall or ceiling section.

Sometimes a small inspection hole is needed to look inside a wall. That is reasonable once readings point to a location. Large exploratory openings without readings first are a warning sign, because they can spread contamination and increase repair costs without telling you much.

Common questions

Should I get air testing to find the source?
Air sampling can indicate whether spore levels inside differ from outdoors, but it rarely pinpoints a location. A moisture-focused inspection is usually the better first step.
Do air purifiers help in the meantime?
A portable HEPA purifier can reduce airborne particles, but it does nothing about the source. Treat it as a stopgap while the moisture problem is found.

General information for Cherry Hills Village, not a quote or professional advice. In an emergency, call 911.