Bottled Water During a Boil Water Advisory: How Much to Buy and How to Use It

The first hour of a boil water advisory is measured in store shelves. Bottled water disappears fast, and the people who arrive late end up buying sparkling mineral water at three times the price or driving to the next town.

Buying bottled water is not complicated, but doing it well means knowing how much you actually need, which type to choose for which purpose, and what bottled water can and cannot do. It is not sterile, it is not unlimited, and it is not free — but during an advisory it is the simplest safe option available.

How much to buy

The CDC’s baseline is one gallon per person per day for three days. For a family of four, that is 12 gallons.

Adjust upward for:

• Pets: about one gallon per medium dog per day; less for cats.
• Infants: formula preparation, bottle rinsing and sterilization add roughly half a gallon per day.
• Cooking: if you cook at home for every meal, add a gallon per day for the household.
• Heat: in summer, people drink considerably more than a gallon.
• Illness: diarrhea and vomiting increase fluid needs.

A practical shopping list for a three-day advisory, family of four: two cases of 24 half-liter bottles (about 6.3 gallons), two 1-gallon jugs for cooking, and one gallon of distilled water for medical devices or a CPAP.

That covers drinking and cooking. Add a few extra gallons if you plan to sponge-bathe children or wash dishes by hand.

Which type of bottled water

Bottled water labels are regulated, but the categories are easy to confuse.

Spring water comes from an underground source and must be collected at the spring or from a borehole. Good general-purpose drinking water.

Purified water has been treated — usually by reverse osmosis, distillation or deionization — and then minerals may be added back. It is consistent and low in contaminants, which makes it a good choice for formula and for people with compromised immunity.

Distilled water has been boiled into steam and condensed, leaving minerals behind. Best for CPAP machines, humidifiers, irons and vehicle cooling systems. It tastes flat and lacks minerals, so it is not ideal as everyday drinking water.

Mineral water contains dissolved minerals, sometimes at high levels. Fine to drink, but not the best choice for infant formula because of the mineral load.

Alkaline or structured water is a marketing category, not a safety category. It offers no advantage during an advisory.

For an advisory, the practical hierarchy is: purified or spring for drinking and cooking, distilled for devices, and skip anything flavored, sparkling or sweetened for emergency use.

How to use bottled water during an advisory

• Drinking: straight from the bottle, or poured into a clean glass.
• Cooking: use it for pasta, rice, soup, coffee and tea. Do not top up with tap water.
• Ice: freeze bottled water, or make ice in trays filled from bottles.
• Brushing teeth: keep a bottle at the bathroom sink. This is the habit most likely to fail.
• Formula: use ready-to-feed if possible. If you must use powder, mix with bottled water — and for newborns under 2 months, use water heated to about 158 °F (70 °C) per CDC guidance to kill *Cronobacter*.
• Pets: pour into a clean bowl; do not let them drink from the bottle.

Important: bottled water is not sterile. It is safe for drinking but not guaranteed free of all microorganisms. For a newborn, a premature baby or an immunocompromised person, ready-to-feed formula or boiled water remains the safer route. Our guide to formula during a boil water advisory covers the details.

Storage and rotation

• Keep bottles out of direct sunlight and away from solvents, gasoline and paint.
• Do not store bottled water in a hot car for long periods; heat degrades the plastic.
• Respect the printed date, and rotate older bottles into everyday use.
• Do not open bottles you are saving for an emergency “just to check.”
• Keep a case in the car and one at work if you commute.

Reusing bottles

A single-use bottle is not designed for repeated refills. The plastic scratches, and scratches harbor bacteria. If you refill, use it for a day or two and then recycle it.

For planned storage, use food-grade containers rather than single-use bottles. Our guide to emergency water storage covers containers and rotation.

Cost and alternatives

Bottled water is expensive per gallon compared with tap water, and during an advisory prices at some stores spike. Options that cost less:

• Bulk jugs (2.5 or 5 gallons) with a dispenser tap.
• Refill stations at grocery stores, if they use treated water — ask the store.
• Utility water stations. During prolonged outages, some utilities set up bulk water distribution points. Bring your own containers.
• Neighbors outside the advisory area. Filling containers at a friend’s tap is free and safe if their water is not affected.

Buying before an emergency is the cheapest strategy of all: a case of water bought in April costs less than a case bought in the first hour of a July advisory.

What bottled water does not solve

• Laundry and showers. Bottled water is for drinking and cooking; you will still need a plan for hygiene. See laundry during a boil water advisory.
• Chemical contamination. Bottled water solves the drinking problem, but not the bathing or cleaning problem in a “do not use” order.
• Long outages. A three-day supply does not cover a two-week outage. Plan for two weeks if you can.

Frequently asked questions

Is bottled water safer than boiled tap water? Both are safe when done correctly. Boiled tap water is cheaper; bottled water is more convenient.

How long can I keep bottled water? Follow the printed date. Unopened bottles stored cool and dark are generally fine for a year or more.

Can I use bottled water for baby formula without boiling? Yes for most babies. For newborns under 2 months, premature babies or immunocompromised infants, use ready-to-feed or water heated to about 158 °F (70 °C) before mixing powder.

Does bottled water need to be boiled during an advisory? No. It is sealed at the source and not connected to the affected system.

What if the store is sold out? Fill clean food-grade containers at a friend’s house outside the advisory area, or check whether your utility has set up a bulk water station.

How much water children actually need

Children drink less than adults in total volume but dehydrate faster, because their body surface area is large relative to their weight. During an advisory, plan for roughly half a gallon of bottled water per child per day for drinking alone, plus what goes into meals.

Three practical points for parents:

• Send a labeled bottle to school or daycare; shared fountains will be off.
• Keep a bottle beside the bed for night-time thirst; children wake up dry-mouthed and reach for whatever is nearest.
• Watch for the signs of dehydration rather than counting ounces: dark urine, headache, irritability and few trips to the bathroom.

Teenagers and athletes need considerably more, especially in summer. If a young athlete is training during an advisory, treat their water needs like an adult’s and add a bottle for post-practice.

Bottom line

Buy 12 gallons for a family of four for a three-day advisory, add for pets and infants, and choose purified or spring water for drinking and cooking with distilled for devices. Store it cool and dark, rotate it, and remember that bottled water is safe but not sterile — newborns need ready-to-feed or properly heated water.

For the full household plan, see what to do during a boil water advisory and emergency water storage.

Sources

• CDC, *How to Create and Store an Emergency Water Supply*: https://www.cdc.gov/water-emergency/about/how-to-create-and-store-an-emergency-water-supply.html
• FDA, *Bottled Water: Questions and Answers*: https://www.fda.gov/food/buy-store-serve-safe-food/bottled-water-questions-and-answers
• CDC, *Infant Formula Preparation and Storage*: https://www.cdc.gov/infant-toddler-nutrition/formula-feeding/preparation-and-storage.html