From Texas Water Utilities:
Myth: A boil water notice means your water is contaminated
Fact: A boil water notice is issued as a precaution anytime the water may have been contaminated.
● Boil water notices are typically issued when an unexpected event has caused a potential for contamination of water in a public water system but DOES NOT indicate that the water is already contaminated.
● Common reasons for a boil water notice include loss of pressure in the distribution system, loss of disinfection, and other unexpected water quality problems.
○ These often result from other events such as water line breaks, treatment disruptions, power outages and floods.
Myth: A boil water notice will always last several days
Fact: It depends on the conditions that caused the need to boil, how quickly the conditions are corrected, and how long it takes for laboratory results to confirm that your water is safe to drink.
● Typically, a boil water event lasts for 24 to 48 hours, but this can be longer and the need to boil water may last for several days or more.
Myth: When a boil water notice is in effect, you cannot use tap water for anything
Fact: You can still use tap water for washing clothes, bathing (not including pets or babies) and watering plants.
● Be careful not to swallow any water when bathing or showering. Use caution when bathing babies and young children. Consider giving them a sponge bath to reduce the chance of them swallowing water.
● Use bottled or boiled water for drinking, brushing teeth, and to prepare and cook food.
● If bottled water is not available, bring water to a full rolling boil for 2 minutes. After boiling, allow the water to cool before use.
Myth: Pets can drink water from natural sources outside, so they don’t need to follow boil water guidelines.
Fact: Pets can get sick from some of the same germs as people or spread germs to people.
● Give pets bottled water or boiled water that has cooled. If bottled water is not available, bring water to a full rolling boil for 2 minutes. After boiling, allow the water to cool before use. Boil tap water even if it is filtered (for example, by a home water filter or a pitcher that filters water). Do not use water from any appliance connected to your water line, such as ice and water from a refrigerator.
Myth: During a boil water notice, you must only wash dishes and glasses by hand in boiled water.
Fact: Household dishwashers are generally safe to use if the water reaches a final rinse temperature of at least 150 degrees Fahrenheit (66°Celsius) or the dishwater has a sanitizing cycle.
● If you are unsure if your dishwasher is safe to use, check with the manufacturer.
Myth: As soon as the boil water notice is lifted, you can safely drink from the tap.
Fact: Following a boil water notice, you will need to flush plumbing, water filters and ice makers to ensure any potential contaminants are cleared.
● To flush your plumbing, run all cold water faucets for at least 5 minutes. Turn the knob as far as you can to ensure the water valve is open all the way.
● Dump existing ice and flush your refrigerator water line by making and discarding three batches of ice cubes.
● To clear hot-water pipes and water heaters, flush the hot water line for a minimum of 15 minutes for a typical household 40-gallon hot-water tank, and 30 minutes for an 80-gallon hot water tank or larger.