Boil-Water Notices: Your Family Plan

The short answer: when your town issues a boil-water notice, follow the notice and boil your water. A filter alone is not the answer, because most portable filters do not remove viruses. And the easiest notice to live through is the one your family was already stocked for.

What do you do the day the notice arrives?

CDC's guidance is direct. If you know or suspect your water is unsafe, do not use it to:

• drink
• wash dishes
• brush your teeth
• wash or prepare food
• wash your hands
• make ice
• make baby formula

Use bottled, boiled or treated water instead, and follow your health department's instructions. (CDC: How to Make Water Safe in an Emergency)

How do you boil water correctly?

CDC calls boiling the best way to kill germs in water. The steps:

1. If the water is cloudy, filter it through a clean cloth, paper towel or coffee filter, or let it settle and draw off the clear water.
2. Bring the clear water to a rolling boil for 1 minute.
3. Let it cool.
4. Store it in clean, sanitized containers with tight covers.

At high elevation, boil longer. CDC says 3 minutes above 6,500 feet. EPA's emergency disinfection page says 3 minutes above 5,000 feet. If you live above 5,000 feet, boil for 3 minutes and you have met both.

Why isn't a filter enough?

This page used to tell you to filter first. That was the wrong order for a boil-water notice. CDC's filter instructions have two steps: run the water through the filter, then add a chemical disinfectant such as iodine, chlorine or chlorine dioxide, because the disinfectant is what kills viruses and bacteria. CDC also notes that disinfectants do not work as well as boiling against some parasites, including Cryptosporidium and Giardia.

So the order during a notice is:

• Boil, if you can.
• If you can only filter, filter and then disinfect, following the label on the tablets or drops.

A good filter still earns its place in your kit. It just is not a substitute for boiling when the notice says boil.

Two hard lines from CDC: if your water may contain fuel or toxic chemicals, use bottled water or a different source and call your health department. And never use water from radiators or boilers in your home heating system.

How much water should you store?

Ready.gov says to store at least one gallon per person per day for several days, for drinking and sanitation. The American Red Cross sets the target at a 3-day supply for evacuation and a 2-week supply at home.

For a family of four, that works out to 12 gallons for three days and 56 gallons for two weeks.

From Ready.gov's water guidance:

• Use food-grade storage containers.
• Replace water that was not commercially bottled every six months.
• Never ration drinking water unless authorities tell you to. Drink what you need today and look for more for tomorrow.

EPA adds two sources many families forget: melted ice cubes and the water in your hot water tank or pipes.

Our guide Emergency Water for Your Family: Store It, Make It Safe, Filter It covers containers, rotation and filters in more depth.

What about babies and formula?

CDC lists baby formula among the things never to make with unsafe water. Ready.gov's advice is to use ready-to-feed formula, and if you must mix formula, to use bottled water, or boiled water as a last resort. If you have an infant at home, keep ready-to-feed formula in your supplies before you ever need it.

What to do this week

• Do the math: people in your home times 14 equals gallons for two weeks.
• Buy or fill that much, and write the date on every container.
• Tape the four boil steps inside a kitchen cabinet door.
• Sign up for alerts from your local emergency management agency, so the notice reaches you the day it is issued.

For the rest of a starter plan, see Diesel, Food Prices, and Your Pantry and Drug Shortages: Build a Medication Buffer.

What's changed since April (updated October 2026)

This brief first ran on April 3, 2026, as "Midwest Water Advisory Reminds Us to Filter First, Trust Later." It reported boil-water notices in three Midwest towns in one week. The original did not name them and we could not re-verify them, so we removed that claim. The old headline put filtering first, and an earlier version said a $25 gravity filter removed that whole category of risk. Both were wrong for a boil-water notice, because most portable filters do not remove viruses. We corrected the advice in October 2026 and removed the paid filter callout. The page now follows CDC, EPA, Ready.gov and American Red Cross guidance.

Reviewed against CDC, EPA, Ready.gov and American Red Cross sources, October 2026.