A chemical storage tank was found leaking into the Elk River, West Virginia, on January 9, 2014. The tank held ~10,000 gallons (38,000 L) of 4- methylcyclohexanemethanol (MCHM). The chemical spilled 2.4 km away from the West Virginia American Water’s (WVAW) Kanawha Valley Water Treatment Plant, traveling downstream and entering the treatment plant (50 MGD). West Virginia Poison Center started to get phone calls from the public, concerned about nausea, vomiting, diarrhea, rashes, and other symptoms. Simultaneously, the emergency departments observed an increase in the visit rates to emergency rooms, which were related to the above-mentioned symptoms. It was determined that the chemical spill ended up in the tap water and started affecting the people who used the tap water and inhaled the contaminated indoor air due to tap water use. This study employed available shower, tap water use at the sink, washing machine and dishwasher models and the reported tap water concentrations for the MCHM to determine the indoor air concentrations of MCHM. The results indicated that the exposure to hazardous levels of MCHM is most likely through showering and while during flushing out of the home plumbing. This study also considered natural and forced ventilation to provide guidance while flushing the home plumbing as it plays a critical role in indoor air concentrations of MCHM.