A Boil Water Advisory (BWA) is a public health notification issued by local authorities when the drinking water supply is, or could be, contaminated with disease-causing microorganisms. This warning instructs residents to take immediate precautions to ensure the safety of water used for consumption and hygiene. The advisory is a temporary safeguard against potential illness until the water system is confirmed safe.
Understanding Why Advisories Are Issued
Boil Water Advisories are typically issued due to an event that compromises the integrity of the water distribution system. A common cause is a loss of pressure in the water mains, which can occur during a main break, a power outage, or fire-fighting operations. When pressure drops significantly, it creates a vacuum that allows potentially contaminated groundwater or soil to be drawn into the pipes.
Advisories are also mandated when water sample tests detect microbial contamination, such as E. coli bacteria or other harmful pathogens. Infrastructure failures, like a broken water line or a problem at the water treatment plant, can also lead to an advisory being issued as a precaution. These microorganisms, including viruses and parasites like Giardia and Cryptosporidium, can cause gastrointestinal symptoms if consumed.
Detailed Steps for Safe Water Boiling
To effectively kill harmful bacteria, viruses, and protozoa, bring the water to a full, rolling boil. A rolling boil is a vigorous, bubbling boil that does not stop when stirred. Once the water reaches this point, maintain the boil for a specific duration to ensure disinfection.
The standard recommendation is to boil the water for one minute at sea level. This duration is sufficient because the temperature of boiling water (212°F or 100°C) rapidly destroys the pathogens that cause waterborne illnesses. However, at higher elevations, lower atmospheric pressure causes water to boil at a cooler temperature.
For locations above 6,500 feet (about 2,000 meters), the Centers for Disease Control and Prevention advises boiling the water for three minutes. This extended time compensates for the lower boiling temperature, ensuring the water is held at a sufficiently high temperature for purification. If the tap water is cloudy, filter it through a clean cloth or coffee filter to remove sediment before boiling. After boiling, allow the water to cool naturally, and store it in a clean, covered container.
Using Water Safely During the Advisory
Even for non-drinking uses, untreated tap water carries risks during an advisory. Do not use tap water for brushing your teeth; instead, use water that has been boiled and cooled or commercially bottled water. When washing hands, you can use tap water and soap, but follow up with an alcohol-based hand sanitizer containing at least 60% alcohol.
When preparing food, use boiled or bottled water for washing fruits and vegetables, and for any cooking that requires adding water. For infants, use ready-to-use formula if possible, or prepare powdered or concentrated formula using boiled and cooled water. Pets should also be given boiled and cooled water or bottled water.
For dishes, household dishwashers are safe if they have a hot cycle that reaches at least 150°F or a sanitizing rinse. If handwashing, dishes should be washed in hot, soapy water and then rinsed for several minutes in boiled water, or soaked in a sanitizing solution of one teaspoon of unscented household bleach per gallon of water. Showering is safe for adults and older children, provided care is taken to avoid swallowing the water. Infants and toddlers should be given a sponge bath to prevent accidental ingestion.
What to Do When the Advisory Is Lifted
Once local officials issue the “all clear,” flush the plumbing system and appliances of any remaining untreated water. The first step is to run all cold water faucets for at least five minutes to purge the service lines. This clears the pipes of potentially contaminated water and replaces it with confirmed safe water.
Next, flush all water-using appliances. Empty and discard all ice made during the advisory, then run the automatic ice maker through three full cycles, discarding the ice each time. Run the dishwasher empty through a hot cycle, and flush refrigerator water dispensers by running at least one quart of water through them. Finally, remove and replace any disposable water filters, such as those in refrigerators or pitcher filters, as they may have trapped contaminants.