Boil water notice: what boiling does not fix

Short answer

A boil water notice means microbes may have entered the distribution system, and boiling is the fix for microbes only. CDC’s emergency water guidance says to bring clear water to a rolling boil for 1 minute, and for 3 minutes at elevations above 6,500 feet. EPA’s emergency disinfection page gives the same one minute but puts the three-minute threshold at 5,000 feet, so follow the wording in the notice your own utility issued. Boiling does nothing for lead, nitrate, PFAS or most chemicals. EPA states that boiling or disinfection will not destroy other contaminants, such as heavy metals, salts, and most other chemicals, and the Minnesota Department of Health says boiling makes nitrate more concentrated against an EPA standard of 10 mg/L measured as nitrogen. During the notice, a filter pitcher is not a substitute and the refrigerator dispenser and ice maker are off limits. When the notice lifts, flush the cold lines and change the cartridges.

If your notice says do not drink and do not boil, stop here and reread it: that is a chemical advisory, and boiling is the wrong response to it.

What does a boil water notice actually cover?

Boiling is heat applied to living organisms. It removes water as steam and leaves everything dissolved behind, slightly more concentrated than before.

What is in the water	Does boiling handle it?	Who says so
Bacteria, viruses, parasites	Yes	CDC, boil water advisory guidance
Lead from a service line or solder	No	EPA: boiling water does not remove lead from water
Nitrate	No, it concentrates it	Minnesota Department of Health
PFAS	No	Minnesota Department of Health
Heavy metals, salts, most other chemicals	No	EPA emergency disinfection page

CDC’s boil water advisory page states it in four words: boiling does NOT remove chemicals. If your concern is a metal or a chemical, the page you want is the one on lead in tap water and service lines, nitrate or PFAS and which filter reduces it.

Utilities are not free to sit on this. EPA’s Public Notification Rule puts any situation with the potential for immediate human health impact in Tier 1, which carries a 24-hour deadline.

How long do you boil, and at what elevation?

One minute at a full rolling boil, per both agencies. The altitude rule is where they part: CDC says 3 minutes above 6,500 feet, EPA says three minutes above 5,000 feet. Print whichever your notice prints, and if it prints neither, the shorter threshold is the cautious one.

CDC adds a step people skip. If the water is cloudy, filter it first through a clean cloth, paper towel or coffee filter, or let it settle and draw off the clear water, then boil.

No way to boil? CDC’s dose for unscented 5 to 9 percent household bleach is 8 drops, about 0.5 mL, per gallon. EPA gives 8 drops of 6 percent bleach or 6 drops of 8.25 percent bleach per gallon. Both are emergency fallbacks, not a routine.

What should you not do while the notice is up?

CDC’s household guidance for a boil water advisory is specific, and most of it is about appliances and habits rather than drinking glasses.

A filter is not a substitute. CDC says to boil tap water even if it is filtered, by a home water filter or a filtering pitcher.
Do not use anything plumbed into the water line. That is the refrigerator dispenser and the automatic ice maker. Switch the ice maker off and dump what is in the bin.
Brush teeth with boiled or bottled water, not untreated tap water.
Give pets bottled water or boiled water that has cooled.
Do not swallow water while bathing or showering. CDC suggests a sponge bath for babies and young children.
Dishes: a dishwasher is acceptable if the final rinse reaches at least 150 degrees F or it has a sanitizing cycle. Washing by hand means rinsing, then soaking in 1 teaspoon of unscented household bleach per gallon of warm water.

Do not buy a filter to get through this

No pitcher, faucet mount or under-sink cartridge changes what CDC says during an advisory: boil the water anyway. Buy a filter for the contaminant that was already in your report, and size it with the cartridge life calculator once the notice is over.

What do you do after the notice lifts?

CDC publishes its recovery checklist for commercial settings rather than households, so read this as facility guidance scaled down to a kitchen. The steps themselves are plumbing, not policy.

Run cold water faucets continuously for at least 5 minutes.
Change every point-of-entry and point-of-use filter, including the ones inside equipment that uses water. That is the whole-house cartridge, the under-sink stack and the fridge filter.
Flush, clean and sanitise the ice maker to the manufacturer’s instructions, and discard the ice already made.
Run a water softener through a regeneration cycle.
Drain and refill a water heater set below 113 degrees F.

Step 2 is the one people skip and the one that matters most: a cartridge that filtered water during the advisory has been collecting what the advisory was about.

When is boiling the wrong response?

CDC names three advisory types, and only one of them is a boil order. A do-not-drink advisory is issued for chemicals or toxins and directs you to commercially bottled water for drinking and cooking. A do-not-use advisory directs you to bottled water for every purpose, including contact with skin, lungs or eyes. CDC notes those are rare.

CDC is blunt about the limit: you cannot deal with water containing fuel, toxic chemicals or radioactive materials by boiling or disinfecting it. Boiling a volatile compound puts it into the room.

That is not theoretical. The California State Water Resources Control Board’s 2025 Los Angeles wildfire recovery page carries a do-not-drink and do-not-boil notice type and states that water should NOT be boiled, as it may pose an inhalation risk. The same page explains why: systems that lost pressure during the fire are susceptible to benzene and other organic compounds in the supply lines. Read the notice type before you fill the pot.

Frequently asked questions

Does boiling water remove lead from an old service line?

No. EPA's lead page states plainly that boiling water does not remove lead from water. Boiling removes water as steam and leaves dissolved metals behind, so the concentration rises rather than falls. EPA's own advice for lead is to flush the pipes before drawing water and to use only cold water for drinking, cooking and making baby formula.

How long do I boil, and does elevation change it?

CDC says to bring clear water to a rolling boil for 1 minute, and for 3 minutes at elevations above 6,500 feet. EPA's emergency disinfection page gives the same one minute but sets the three-minute threshold at 5,000 feet. The two agencies differ, so follow the wording in the notice your own utility issued.

Can I use my filter pitcher or fridge dispenser instead of boiling?

No. CDC's boil water advisory guidance says to boil tap water even if it is filtered, including by a home water filter or a filtering pitcher. It also says not to use water from any appliance connected to the water line, which covers the refrigerator dispenser and the automatic ice maker. Switch the ice maker off.

What is a do-not-drink or do-not-use advisory?

CDC defines three advisory types. A boil water advisory covers germs and boiling handles them. A do-not-drink advisory is issued for chemicals or toxins and directs you to commercially bottled water for drinking and cooking. A do-not-use advisory directs you to bottled water for every purpose, including contact with skin, lungs or eyes. CDC notes do-not-use advisories are rare.

How fast does a utility have to tell me?

EPA's Public Notification Rule sets three tiers. Tier 1 covers situations with the potential for human health to be immediately impacted and requires notice within 24 hours, which is the tier a boil water notice falls under. Tier 2 allows up to 30 days, and Tier 3 up to one year for paperwork violations such as a missed sample.

Fact sheet and how to cite this page

Answer: A boil water notice covers microbes only. CDC’s emergency water guidance gives 1 minute at a rolling boil, 3 minutes above 6,500 feet, while EPA’s emergency disinfection page sets that altitude threshold at 5,000 feet. EPA states boiling will not destroy heavy metals, salts and most other chemicals, so lead, nitrate and PFAS pass straight through.
Basis: CDC, How to Make Water Safe in an Emergency (1 minute rolling boil, 3 minutes above 6,500 feet) and EPA, Emergency Disinfection of Drinking Water (one minute, three minutes above 5,000 feet)
Assumptions: A public water system has issued a boil water notice, not a do-not-drink or do-not-use advisory
Water is clear; cloudy water is filtered through cloth or a coffee filter before treatment
Post-notice recovery steps are CDC’s commercial-setting guidance applied to a household
Method: Boiling duration, elevation thresholds and the limits of boiling were read this session from CDC’s emergency water pages and EPA’s emergency disinfection page. The chemical exclusions were confirmed against EPA’s lead page, the Minnesota Department of Health nitrate and PFAS pages, and CDC’s advisory overview, all cited below.
Primary source: CDC, How to Make Water Safe in an Emergency (government or regulatory source)
Facts verified: 21 September 2026
Last updated: 21 September 2026
Canonical URL: https://ownerspec.com/water/guides/boil-water-notice-what-it-does-not-fix/
Cite as: OwnerSpec, "Boil water notice: what boiling fixes, what it does not fix, and what to do once it lifts", https://ownerspec.com/water/guides/boil-water-notice-what-it-does-not-fix/, facts verified 21 September 2026.

Every figure above also appears, with its source, in the article. All sources · How OwnerSpec verifies numbers

Sources

CDC, How to Make Water Safe in an Emergency (government or regulatory source)
CDC, Boil Water Advisory (Natural Disasters PSA toolkit) (government or regulatory source)
CDC, Preventing Cryptosporidiosis at Home During a Boil Water Advisory (government or regulatory source)
CDC, Preventing Cryptosporidiosis in Commercial Settings During a Boil Water Advisory (government or regulatory source)
CDC, Drinking Water Advisories: An Overview (government or regulatory source)
EPA, Emergency Disinfection of Drinking Water (government or regulatory source)
EPA, Basic Information about Lead in Drinking Water (government or regulatory source)
EPA, Public Notification Rule (government or regulatory source)
Minnesota Department of Health, Nitrate in Drinking Water (government or regulatory source)
Minnesota Department of Health, PFAS and Home Treatment of Water (government or regulatory source)
California State Water Resources Control Board, 2025 Los Angeles Wildfire Recovery (government or regulatory source)