Shower water is engineered to clean the body, not to be ingested. While a accidental sip from the showerhead is usually harmless, deliberately drinking shower water is not recommended due to the specific chemistry and stagnation that occurs in a home’s plumbing system.
Why Shower Water Isn't Designed for Drinking
The primary purpose of water delivered to a shower is hygiene and temperature control, not consumption. Unlike water from a kitchen tap, which is often flushed through newer pipes and used frequently, shower water can sit stagnant in the showerhead and the upper reaches of the plumbing system for hours. This stagnation creates an environment where bacteria can grow and where chemical interactions with the pipe materials are more likely to occur.
The Issue of Stagnation
When water sits unused, it can develop a stale taste and potentially harbor higher levels of bacteria. This is common in guest bathrooms where the shower is not used daily. The water sitting in the pipes between the main supply and the showerhead is essentially dead water, lacking the flow and aeration that keeps drinking water fresh and clear.
Chemical Additives and Treatments
Municipal water supplies are treated with chlorine or chloramine to kill pathogens. These chemicals are safe to consume at the levels found in drinking water standards, but they are intended to be ingested in small, controlled doses via the main water line. In a shower, the water is often heated, which can cause these chemicals to vaporize. Inhaling this vapor during a hot shower is the primary exposure for most people, rather than ingestion.
Heavy Metals and Plumbing Materials
Older homes may have plumbing fixtures or pipes that contain lead, copper, or other metals. While the main drinking water tap is often flushed to clear this water, the showerhead can accumulate these metals over time. Hot water can also cause more metal to leach from the pipes and into the standing water in the shower system, making it potentially more hazardous than the water used for washing dishes.
Bacterial Concerns Showerheads are known to harbor biofilm—a collection of bacteria, mold, and other microorganisms that thrive in the warm, moist environment. While most of these bacteria are harmless to healthy individuals, they can pose a risk if ingested, particularly for people with compromised immune systems. The National Geographic has highlighted studies showing that showerheads can contain significant amounts of mycobacterium, which can cause lung infections if inhaled, though the risk of swallowing them is lower. When Is It Accidentally Considered?
Showerheads are known to harbor biofilm—a collection of bacteria, mold, and other microorganisms that thrive in the warm, moist environment. While most of these bacteria are harmless to healthy individuals, they can pose a risk if ingested, particularly for people with compromised immune systems. The National Geographic has highlighted studies showing that showerheads can contain significant amounts of mycobacterium, which can cause lung infections if inhaled, though the risk of swallowing them is lower.
Accidental ingestion can happen when brushing teeth or rinsing the mouth in the shower. If this occurs, the risk is generally low for a healthy person. The water has been heated and exposed to the air and piping, but a single small incident is unlikely to cause serious health issues. Simply rinsing the mouth with fresh tap water afterward is sufficient to mitigate any concern.
Recommendations and Best Practices
To ensure safety, it is best to use dedicated drinking water sources, such as filtered pitchers or bottled water, rather than relying on shower water. If a household chooses to use shower water for other purposes, letting the water run for a minute before filling a container can help flush out stagnant water and reduce the concentration of metals and bacteria.
