A Boil Water Advisory (BWA) is a public health notification advising residents that their tap water may be contaminated with disease-causing microorganisms, such as bacteria, viruses, or parasites. Advisories are typically issued following events like water main breaks, loss of system pressure, or natural disasters that compromise the water distribution system. Untreated tap water is unsafe for oral hygiene, meaning you cannot brush your teeth with it during an advisory.
Understanding the Risk of Unboiled Water
Using contaminated water for brushing presents a genuine risk of ingestion, even if you try to spit it all out. Pathogens like E. coli, Giardia, and Cryptosporidium can be present, and even tiny amounts accidentally swallowed can lead to gastrointestinal illness. Symptoms often include diarrhea, nausea, vomiting, and abdominal cramps.
The moist, thin, and sensitive tissues inside the mouth, including the gums, can also absorb these harmful microorganisms. This absorption offers a pathway for bacteria and viruses to enter the bloodstream, potentially leading to systemic health issues. Public health guidance recommends eliminating all risks of ingesting untreated water. This precaution is especially important for vulnerable populations, including the elderly, very young children, and those with weakened immune systems.
Safe Water Sources for Oral Care
Since tap water cannot be used directly, the two safe alternatives for oral care are commercially bottled water or properly boiled tap water. Using either of these sources ensures that your toothbrush is wetted and your mouth is rinsed with water free of harmful pathogens. The water must be safe for both rinsing and wetting your brush before applying toothpaste.
To prepare tap water safely, you must bring it to a full, rolling boil that produces large, rapid bubbles. Keep the water at a rolling boil for a minimum of one full minute to effectively kill protozoa, bacteria, and viruses. If you live at elevations above 6,500 feet, you must boil the water for three minutes due to the lower boiling point.
After boiling, the water must be allowed to cool completely before it is used for brushing, as hot water can cause oral burns or damage the toothbrush. Once cooled, store the safe water in a clean container with a cover to prevent recontamination. Even if you use a home water filter, such as a pitcher filter, you must still boil the tap water, as most household filters are not designed to remove micro-organisms like bacteria and viruses.
Beyond Brushing: Rinsing and Denture Care
The use of safe water extends beyond the brushing process to all other aspects of oral hygiene. When rinsing your mouth after brushing with safe water, take care not to swallow any of the water, minimizing any residual risk. Using a small amount of safe water is a good practice to ensure you do not accidentally ingest any.
For individuals who use dental appliances like dentures or retainers, cleaning and soaking must also be done with safe water. Brush appliances with boiled and cooled water or bottled water, and any soaking solution must be prepared using the same safe water source. Dentures should never be placed in hot or boiling water for cleaning, as the heat can cause the material to warp and change shape.
If you use dental floss, the act of flossing itself is safe since it does not require water. However, wash your hands with an alcohol-based hand rub or soap and safe water both before and after flossing. If you have already used untreated tap water to wet your toothbrush before the advisory, health experts suggest replacing the toothbrush head to eliminate potential contamination lingering in the bristles.