Health experts warn against using showerhead water for oral hygiene

Medical experts are warning against the habit of using showerhead water for rinsing the mouth or brushing teeth, particularly in older showerheads that have not been frequently cleaned.

Lim Jae-joon, a respiratory specialist at Seoul National University Hospital, noted that bacteria can accumulate inside showerheads and be dispersed through the water. A specific concern is non-tuberculous mycobacteria (NTM), a group of bacteria commonly found in soil and water.

The Centers for Disease Control and Prevention (CDC) has indicated that these bacteria can exist in domestic water supplies and common fixtures. The risk is often linked to the formation of biofilms—microbial layers that cling to moist surfaces like the interior of pipes or showerheads. These films are often invisible to the naked eye, meaning a showerhead may appear clean externally while harboring microorganisms internally.