Your city just issued a boil water advisory. Your first instinct might be to panic and buy out every bottle of water at the grocery store. Take a breath. You have time, and you have options. This guide walks you through exactly what to do in the next 30 minutes, what you can and cannot use tap water for during the advisory, and how to stay safe until it is lifted.
About 2,000 boil water advisories are issued across the United States every year. They are more common than most people think, and they are almost always precautionary. The water might be contaminated. The advisory exists to keep you safe while the utility confirms it is clean. Your job right now is simple: follow the steps below and go about your day.
Key Takeaways
- Stop using unboiled tap water for drinking, cooking, brushing teeth, and pet bowls immediately
- Bring water to a full rolling boil for 1 minute (3 minutes above 6,500 ft elevation), then let it cool
- You can still shower, wash hands with soap, and do laundry — just do not swallow the water
- Dump your ice maker bin and turn off the ice maker until the advisory is lifted
- After the advisory ends, flush all cold taps for 5 minutes and make fresh ice
- Having a portable water filter or purification tablets on hand eliminates the scramble next time
What Is a Boil Water Advisory?
A boil water advisory is an official notice from your water utility or local health department telling you that your tap water may be contaminated with bacteria, viruses, or parasites. Notice the word "may." Most advisories are precautionary. Something happened — a water main break, a drop in water pressure, a treatment plant issue, flooding — that created a possibility of contamination.
The utility issues the advisory while they test the water. Testing takes time, usually 24 to 48 hours. In the meantime, the advisory tells you to treat all tap water as if it were contaminated. Once tests come back clean, the advisory is lifted and life goes back to normal.
This is not a reason to panic. It is a reason to follow a simple process.
Immediate Steps: Your First 30 Minutes
You just found out about the advisory. Here is your action checklist, in order of priority.
Do These Right Now
- Stop using tap water for drinking and cooking. Turn off anything actively using tap water for consumption — coffee makers, cooking pots, baby formula preparation.
- Boil water for immediate needs. Fill your largest pot, bring to a rolling boil for 1 minute (3 minutes if you live above 6,500 ft), then let it cool in a clean, covered container.
- Dump your ice bin. All ice made since before the advisory is potentially contaminated. Empty the bin and turn off the ice maker.
- Disconnect your fridge water line or stop using the dispenser and in-door water until the advisory lifts.
- Switch to bottled water if you have it. This is the easiest short-term solution for drinking and brushing teeth.
- Fill containers with boiled water. Boil a large batch and store it in clean, covered pitchers or bottles so you are not re-boiling every time you need a glass.
- Tell everyone in your household. Make sure kids, roommates, and guests know not to drink from the tap.
Tip: Boil more than you think you need. A family of four goes through about a gallon of drinking water per person per day. Boil at least 2 gallons at a time and keep it in covered containers on the counter.
What You CAN and CAN'T Do With Tap Water
This is where most people get confused. Not everything is off-limits during a boil advisory. Here is the clear breakdown.
Safe to Do
- Wash hands with soap (20+ seconds)
- Shower or bathe (don't swallow)
- Do laundry as normal
- Flush toilets
- Run dishwasher on sanitize cycle (150°F+)
- Water non-edible plants
NOT Safe
- Drink unboiled tap water
- Cook with unboiled tap water
- Brush teeth with tap water
- Wash dishes by hand (without bleach rinse)
- Make baby formula with tap water
- Give tap water to pets
- Use tap water ice cubes
- Rinse fruits/vegetables
Warning — Babies and immunocompromised: For infants, use only boiled and cooled water or bottled water for formula, food prep, and bathing. People with weakened immune systems should use boiled or bottled water for everything, including handwashing. Do not take chances.
How to Boil Water Correctly (Step-by-Step)
This sounds simple, and it is. But the details matter, because half-boiled water does not eliminate pathogens.
Step 1: Fill a Clean Pot
Use the largest pot you have. If the water looks cloudy or has visible particles, filter it first through a clean cloth, coffee filter, or paper towel into the pot. This removes sediment but does not kill pathogens — that is what the boiling does.
Step 2: Bring to a Rolling Boil
A rolling boil means large bubbles continuously breaking the surface. Small bubbles clinging to the bottom of the pot do not count. You want a vigorous, churning boil. Once you reach that point, start your timer.
- Below 6,500 ft elevation: Boil for 1 full minute
- Above 6,500 ft elevation: Boil for 3 full minutes (water boils at a lower temperature at altitude, so you need more time)
Step 3: Let It Cool
Remove the pot from heat. Cover it with a clean lid and let it cool to room temperature. Do not add ice to speed up cooling — the ice is contaminated too. Patience. It takes about 30 to 45 minutes for a full pot to cool enough to drink.
Step 4: Store Properly
Pour cooled water into clean containers with lids. Glass pitchers, clean water bottles, or food-grade plastic containers all work. Keep them covered. Label them "boiled" so nobody confuses them with tap water. Boiled water stays safe at room temperature for 24 hours, or longer in the refrigerator.
Tip: Boiling will not remove chemical contaminants like lead or PFAS. If your advisory specifically mentions chemical contamination (rare), bottled water or a certified filter is the only option. Standard boil advisories are about biological contaminants — bacteria, viruses, and parasites — which boiling destroys completely.
Alternatives If You Cannot Boil
Power outage? Camping stove ran out of fuel? No way to boil water? You still have options. These are the three most reliable alternatives, ranked by effectiveness.
1. Water Purification Tablets
Chemical purification tablets are the simplest backup. Drop them in water, wait the specified time (usually 30 minutes to 4 hours depending on the product), and the water is safe to drink. They kill bacteria, viruses, and most parasites.
Water Purification Tablets
Chlorine dioxide tablets (like Potable Aqua or Aquatabs) treat water in 30 minutes to 4 hours. Lightweight, inexpensive, and effective against bacteria, viruses, and Giardia. A single bottle treats 25–30 gallons.
Pros
- No power or equipment needed
- Under $15 for 50 tablets
- 5-year shelf life unopened
- Fits in a drawer or go-bag
Cons
- Wait time (30 min to 4 hours)
- Slight chemical taste
- Less effective on Cryptosporidium
2. Portable Water Filters
Gravity filters, squeeze filters, and straw filters physically remove pathogens from water. Unlike tablets, they work instantly — no waiting. The Sawyer Squeeze is the gold standard: rated for 100,000 gallons, removes 99.99999% of bacteria and 99.9999% of protozoa, and costs about $35.
Portable Squeeze or Gravity Filter
Filters like the Sawyer Squeeze or a gravity-fed system remove bacteria and protozoa on contact. Fill, squeeze (or let gravity do the work), and drink. No boiling, no chemicals, no waiting.
Pros
- Instant clean water
- No power or fuel needed
- Filters 100,000+ gallons
- Removes bacteria and protozoa
Cons
- Does not remove viruses (rare in US water)
- Requires periodic backflushing
- Gravity models are slower
3. UV Water Purifiers
UV purifiers use ultraviolet light to destroy the DNA of bacteria, viruses, and protozoa. The SteriPEN Ultra treats 16 ounces of water in 90 seconds. It is the only portable method that reliably kills viruses, making it a strong complement to a filter.
SteriPEN Ultra UV Purifier
USB-rechargeable UV purifier that destroys 99.9% of bacteria, viruses, and protozoa in 90 seconds. Treats up to 8,000 liters on a single UV lamp. Compact enough for a kitchen drawer or go-bag.
Pros
- Kills viruses (filters cannot)
- 90 seconds per treatment
- USB rechargeable
- No chemical taste
Cons
- Requires battery/power
- Does not remove sediment
- Only treats clear water
- ~$80–100 price point
4. Water Purification Drops
Liquid purification drops like Aquamira Water Treatment Drops use chlorine dioxide in a two-part solution. Mix the drops, add to water, wait 15 to 30 minutes. They treat large quantities efficiently and have a 5-year shelf life. A single kit treats up to 60 gallons — enough to get a family through a week-long advisory.
Best practice: Keep at least two methods on hand. A squeeze filter for daily use, plus purification tablets or drops as a backup. Redundancy is the entire point of emergency preparedness.
After the Advisory Is Lifted
The advisory is over. The water utility has confirmed the water is safe. But you are not done yet. Contaminated water may still be sitting in your pipes, ice maker, and appliance lines. Here is how to flush it out.
Post-Advisory Checklist
- Flush all cold water faucets for at least 5 minutes each. Start with the faucet closest to where water enters your home and work outward. Let the water run until it is clear and cold.
- Flush your hot water system. Run hot water taps for 5 minutes. If you have a tankless heater, this is quick. If you have a tank heater, you may need to run it longer or drain the tank.
- Flush your refrigerator water line. Run the dispenser for 3 to 5 minutes. Discard the first batch of water. Replace the fridge water filter if it was used during the advisory.
- Dump all ice. Every cube made during or before the advisory goes in the trash. Turn the ice maker back on and discard the first batch of new ice too, just to be safe.
- Run your dishwasher empty on the hottest cycle to flush the internal lines.
- Clean and flush any water-using appliance: coffee maker (run a full water-only brew cycle), humidifier, CPAP machine, pet water fountain.
- If you have a water softener, run a manual regeneration cycle to flush the resin bed.
The entire flushing process takes about 20 to 30 minutes. It is worth doing properly. The advisory may be over, but old water is still sitting in your pipes from when it was not.
How to Be Ready Before the Next One
You just went through this. You know it is not fun scrambling to boil water while your kids are asking why they cannot have a glass from the tap. Here is how to eliminate the scramble entirely.
The 5-Minute Prep Kit
Everything below fits in a single kitchen drawer or cabinet shelf. Total investment: under $60. Total peace of mind: immeasurable.
- One case of bottled water (24-pack) — rotated every 6 months, used for drinking and brushing teeth
- Water purification tablets — 50 tablets, treats 25+ gallons, $10–15
- Aquamira water treatment drops — backup to tablets, treats 60 gallons, ~$15
- Portable squeeze filter — Sawyer Squeeze or similar, $30–35
- Two clean 1-gallon containers with lids — for storing boiled water
- A printed copy of this checklist on the inside of your cabinet door
That is it. Six items. Under $60. When the next advisory hits, you open the drawer, grab what you need, and skip the panic entirely.
For a More Complete Setup
If you want to go beyond the basics — and you should, because advisories are just one of many reasons you might lose access to clean water — check out these resources:
- Emergency Water Storage Guide — how much to store, which containers to use, and treatment methods
- Emergency Water Purification Methods at Home — 7 proven methods beyond boiling
- Best Water Filters for Emergencies — tested and ranked for reliability
- Best Gravity Water Filters (Berkey Alternatives) — whole-family filtration without power
The bigger picture: A boil water advisory is a wake-up call. It is your water system telling you that things can go wrong, even briefly. The people who handle it calmly are the ones who spent 10 minutes preparing before it happened. Be that person.
What Causes Boil Water Advisories?
Understanding why these happen helps you take them seriously without overreacting.
Water Main Breaks
The most common cause. When a pipe breaks, the pressure drop can allow soil, groundwater, or sewage to seep into the water supply. Repairs fix the pipe, but the water needs to be tested before the advisory lifts. This typically takes 24 to 48 hours.
Treatment Plant Issues
Equipment failure, power outages at the plant, or a chemical dosing error can temporarily reduce water treatment effectiveness. These are usually resolved quickly, but the testing protocol still takes 1 to 2 days.
Flooding and Natural Disasters
Heavy rain, hurricanes, and floods can overwhelm water systems. Floodwater carries bacteria, sewage, and chemicals. These advisories tend to last longer — sometimes a week or more — because the contamination source is external and widespread.
Positive Bacteria Tests
Water utilities regularly test for coliform bacteria. A positive test triggers an automatic advisory while they investigate. In many cases, the contamination is localized or the test result is a false positive. But they issue the advisory anyway, because the cost of caution is low and the cost of being wrong is high.
Special Situations
Baby Formula
Use only boiled and cooled water or bottled water labeled "purified" or "distilled" for mixing formula. Do not use water from a filter alone — most portable filters do not remove viruses, and infants are especially vulnerable to waterborne illness. Boiling is the safest option.
Pets
Treat your pets the same as yourself. Boiled and cooled water or bottled water in their bowl. Dogs, cats, birds, and reptiles are all susceptible to the same pathogens. Fill a large bowl once per day so you are not constantly reboiling.
Medical Equipment
CPAP machines, humidifiers, nebulizers, and any device that uses water should only use boiled, distilled, or bottled water during the advisory. After the advisory lifts, clean and disinfect these devices before returning to tap water.
Restaurants and Food Businesses
If you run a food business, stop all food prep with tap water immediately. Switch to bottled water for cooking and dishwashing. Notify your local health department. Most jurisdictions require you to post a notice for customers. Document everything — your compliance matters if questions come later.
Build Your Water Safety Kit Today
Do not wait for the next advisory. A basic kit costs under $60 and eliminates the scramble. Filter, tablets, storage — done.
Browse Water Filters →Read: Best Water Purification Tablets
Frequently Asked Questions
Most advisories last 24 to 48 hours. Minor issues like a localized pipe break can resolve in a few hours. Larger events, especially flooding or widespread infrastructure failures, can keep advisories in place for a week or more. Check your local water utility's website or social media for real-time updates specific to your area.
Yes, adults and older children can shower as normal. Keep your mouth closed and avoid swallowing water. For infants or people with compromised immune systems, a sponge bath with boiled and cooled water is the safer choice. If you have open wounds or recent surgical sites, use boiled or bottled water to clean those areas.
A dishwasher with a sanitize cycle that reaches at least 150°F (65°C) is safe to use. Hand-washing dishes with tap water alone is not recommended. Either wash with boiled water, add 1 tablespoon of unscented bleach per gallon of water for a sanitizing rinse, or switch to disposable plates and utensils until the advisory lifts.
No. Pets are susceptible to the same waterborne pathogens that affect humans, including E. coli and Giardia. Give your pets boiled and cooled water or bottled water. Fill a large bowl once per day so you do not have to reboil every time they are thirsty.
Flush all cold water taps for at least 5 minutes each. Run your fridge water dispenser for 3 to 5 minutes and discard the first batch. Dump all ice and make fresh. Run your dishwasher empty on a hot cycle. Clean any appliance that uses water: coffee maker, humidifier, CPAP. If you have a water softener, run a manual regeneration cycle.