There are many ways buildings become home to a toxic mix of microbes, fragments of microbes, and harmful chemicals. Buildings can promote the growth of fungi, bacteria, mycobacteria and actinomycetes as a result of construction defects like poor ventilation and HVAC systems; faulty construction of crawl spaces or inadequate building design; using failed technologies like flat roofs or fake stucco cladding without adequate caulking; incomplete basements exposed to saturated ground water conditions; or not correcting water intrusion/leaks; or remediation that doesn't clean as its final requirement.

The Occupational Safety and Health Administration (OSHA) tells us that more than a quarter of U. S. buildings are water-damaged.

Simply stated, water drives the growth of mold and bacteria.