The plumbing puzzle: Why shower water is different
Even if your city’s water is perfectly safe to drink from the kitchen tap, the water delivered to your shower has a different path and is exposed to different conditions. This is particularly true for hot water, which is stored in a water heater for extended periods. This prolonged storage in a warm environment creates an ideal breeding ground for harmful bacteria, which are not present in cold, fresh tap water.
The water heater hazard
Your water heater is a common culprit for contamination. Water sits in the tank for long periods, allowing sediment and scale to build up. This stagnant, warm water is an optimal environment for bacteria like Legionella, the cause of Legionnaires' disease, to multiply. While you are unlikely to swallow enough water to get sick from a single accidental gulp, regularly drinking this water significantly increases your risk of exposure. Additionally, heating water can increase the rate at which heavy metals, such as lead and copper, leach from older pipes and fixtures. Always use cold water from the tap for drinking and cooking to avoid these potential health issues.
The dirty showerhead dilemma
Another major source of contamination is the showerhead itself. A 2009 study by the University of Colorado Boulder and the CDC found that nearly a third of all tested showerheads contained significant levels of Mycobacterium avium, a bacterium that can cause lung disease in susceptible individuals. The moist, dark, and warm interior of a showerhead is a perfect habitat for these microbes to form biofilms, which are difficult to remove with standard cleaning. As water sprays through the showerhead, these bacteria can become aerosolized and inhaled, or even accidentally ingested. This is a risk that doesn't exist with drinking directly from the cold tap.
Aging pipes and fixtures
Many homes have older plumbing that can contain lead pipes or copper pipes with lead solder, particularly those built before 1986. While federal regulations have since banned lead in pipes, older homes may still pose a risk. Drinking hot water increases the likelihood of lead leaching from these old pipes. The water in your bathroom often travels through these less-used and potentially older lines, whereas the kitchen tap might be a more direct route to the main water supply, though this isn't always the case. Using a point-of-use filter at the kitchen sink is a common and effective solution for ensuring your drinking water is as pure as possible.
What about filtered shower water?
Some people use showerhead filters to remove chlorine and other irritants for skin and hair health. While these filters are beneficial for their intended purpose, they are not designed or certified to make water safe for drinking. They typically lack the necessary filtration stages to remove bacteria, heavy metals, and other contaminants that can accumulate within the plumbing system. Relying on a shower filter for drinking water safety is a dangerous and incorrect assumption.
Comparison: Kitchen tap vs. shower water
To better illustrate the differences, here is a comparison of water from your kitchen tap (intended for consumption) versus shower water.
| Feature | Kitchen Tap Water | Shower Water |
|---|---|---|
| Source | Usually comes directly from the main water line, or passes through a whole-house filter. | Travels through the home's internal plumbing, including potentially older pipes and the water heater. |
| Temperature | Typically accessed as cold water, reducing metal leaching and bacterial growth. | Often mixed with heated water, which can increase bacterial levels and leach heavy metals. |
| Storage | Does not sit stagnant in a warm tank, resulting in fresher, cleaner water. | Is stored in a warm water heater, a potential breeding ground for bacteria like Legionella. |
| Filtration | Can be filtered with point-of-use systems certified for drinking water safety. | May pass through a filter for skin health, but these are not certified for safe drinking water. |
| Contamination | Lower risk of bacteria from plumbing and fixtures due to higher usage and no storage in a warm tank. | Higher risk from bacterial biofilms in showerheads and contaminants leached from aging pipes. |
The bottom line for your health
Your body is a finely tuned machine, and a key part of keeping it running well is proper hydration with clean water. Drinking water with potential contaminants, even in small amounts over time, can have long-term negative effects. From gastrointestinal issues caused by bacteria to exposure to heavy metals, the risks far outweigh the convenience of an impromptu drink from the shower. The safest and most reliable source for potable water is always the cold tap in your kitchen. If you are concerned about your home’s water quality, consider getting a professional water test to identify any specific issues.
In conclusion, the practice of drinking water from your shower is not recommended. For your health and safety, stick to a trusted source for drinking water. The Centers for Disease Control and Prevention (CDC) offers further resources on maintaining safe and healthy drinking water in your home.
