While the dog’s nose is the tool, the handler is the key to accuracy. A skilled handler not only keeps the dog trained but also reads the dog’s cues and interprets alerts in context. For example, a mold dog may alert on a baseboard where MVOCs are seeping through from a hidden wall cavity. It’s the handler’s job to identify whether the alert points to a real concern or might be due to trace mold scents carried on air currents from another part of the house.

Over time, dogs may learn to alert even when there’s no mold present, simply to receive praise or a treat. This is known as over-alerting. A good handler prevents this through regular retraining, staying objective, and never rewarding false alerts. They also know when to question an alert and when to trust their dog. The human-dog partnership is a dynamic and ongoing process built on trust, practice, and continual learning.

Handlers also act as educators, explaining to homeowners what the dog is reacting to, how the alert process works, and why a mold dog inspection is just one part of a comprehensive mold investigation. A strong handler will always recommend visual confirmation or follow-up by an Indoor Environmental Professional (IEP) for areas the dog alerts on.