The notice governs. This is what it does not say.
A boil water notice is issued by your utility or health department for a specific reason, and their instruction is the one to follow — they know why it was issued and when it lifts.
What follows is EPA’s general emergency guidance, and one thing the notice itself will almost never tell you.
What boiling reaches
EPA is precise about the scope:
Boiling is sufficient to kill pathogenic bacteria, viruses and protozoa.
Bring water to a rolling boil for at least one minute. At altitudes above 5,000 feet, boil for three minutes. Let it cool naturally and store it in clean containers with covers.
If the water is cloudy, let it settle and filter it through a clean cloth, paper towel or coffee filter first.
Use disinfected water for “drinking, cooking, making any prepared drink, washing dishes and for brushing teeth.”
One clarification worth having. Protozoa includes Cryptosporidium and Giardia. EPA’s surface water rules do not credit a chlorine residual with inactivating Cryptosporidium — the requirement there is removal — but boiling is thermal, and EPA states it is sufficient. So the organism a plant cannot chlorinate away, a kettle can.
→ Cryptosporidium and Giardia, and why EPA requires removal
What boiling does not reach, and what it makes worse
This is the part the notice does not cover, and it matters to a specific set of households.
EPA:
However, boiling or disinfection will not destroy other contaminants, such as heavy metals, salts, and most other chemicals.
And separately, on lead: “boiling water does not remove lead from water.”
Minnesota Department of Health goes further on nitrate: boiling “does not remove nitrate and makes it more concentrated.” The mechanism is the same for anything dissolved — water leaves as steam, the contaminant stays.
So a boil notice instructs you to do the one thing that concentrates lead and nitrate. For microbes that is exactly right. For a household with a lead service line or a nitrate result, boiled water is the wrong water for drinking and formula during the notice.
→ Lead: the action level, and what your utility owes you → Nitrate, and why boiling is the wrong instinct
Bottled water is the answer for those uses, and EPA puts it ahead of every alternative in an emergency regardless.
If you cannot boil
EPA’s household bleach method, for when boiling is not possible.
Use regular, unscented chlorine bleach whose label indicates it is suitable for disinfection and sanitisation, with 6 or 8.25 percent sodium hypochlorite, stored at room temperature for less than one year. Not scented, not colour-safe, not with added cleaners.
| Water volume | 6% bleach | 8.25% bleach |
|---|---|---|
| 1 quart or litre | 2 drops | 2 drops |
| 1 gallon | 8 drops | 6 drops |
| 2 gallons | 16 drops (¼ tsp) | 12 drops (⅛ tsp) |
| 4 gallons | ⅓ teaspoon | ¼ teaspoon |
| 8 gallons | ⅔ teaspoon | ½ teaspoon |
Double the dose if the water is cloudy, coloured or very cold. Stir and let stand 30 minutes. The water should have a slight chlorine odour — if it does not, repeat the dose and stand another 15 minutes before use.
This method is chemical disinfection and carries the same limit as boiling: it does not destroy heavy metals, salts or most chemicals.
The decision framework
1. Read the notice, not this page
It names the reason and the area, and only your utility knows when it lifts.
2. Decide whether boiling is right for your household
If the concern is microbial only, boiling is the correct response and EPA’s timings apply.
If you have a lead service line, or a nitrate result, boiled water is not suitable for drinking or formula. Use bottled for those uses and boiled water for dish-washing and tooth-brushing if the notice permits.
If an infant is bottle-fed, that combination is the sharpest case on this page: nitrate concentrates, and infants under six months are the group MDH identifies as most at risk.
3. Sort your water sources before you need them
EPA puts bottled first and lists melted ice cubes, a hot water tank or pipes as alternatives, with flowing water preferable to stagnant and nothing used that has floating material, dark colour or a questionable odour.
4. Do not assume a filter substitutes
A certified filter holds claims for named contaminants under normal supply conditions. A boil notice is not normal supply conditions, and the notice governs regardless of what is fitted.
→ What a certified claim covers, and when it stops
The decision path
| Your situation | What decides it | Where that lands you |
|---|---|---|
| Notice issued, no other concerns | Microbial risk | Boil one minute, three above 5,000 ft |
| Cloudy water | Clarity before disinfection | Settle and filter, then boil |
| Cannot boil | No heat available | EPA’s bleach method, 30 minutes |
| Lead service line | Boiling does not remove lead | Bottled for drinking and formula |
| Nitrate on the report | Boiling concentrates it | Bottled for drinking and formula |
| Bottle-fed infant | Both risks at once | Bottled water, without exception |
| Notice lifted | Only the utility knows | Follow their flushing instruction |
Choose boiling if
- The notice is microbial and you have no lead or nitrate concern.
- You can reach a rolling boil and hold it for the stated time.
Choose the bleach method if
- You cannot boil, and you have suitable unscented chlorine bleach less than a year old.
Choose bottled water if
- You have a lead service line or a nitrate result, for drinking and formula.
- An infant is bottle-fed. EPA puts bottled ahead of the alternatives in an emergency, and the concentration problem removes the alternative anyway.
Mistakes that cost the most money, or more
Assuming boiling handles everything. EPA names heavy metals, salts and most chemicals as outside what boiling or disinfection destroys.
Boiling with a lead service line. EPA states boiling does not remove lead, and the water lost as steam concentrates what remains.
Boiling with nitrate present. MDH states it makes nitrate more concentrated. With a bottle-fed infant this is the most consequential error on the page.
Using scented or colour-safe bleach. EPA excludes those, and bleaches with added cleaners.
Skipping the settle-and-filter step on cloudy water. EPA puts it before both boiling and chemical disinfection.
Treating a fitted filter as an exemption. The notice applies to the supply, not to your plumbing downstream of it.
Three situations, and what changes
A main break, notice issued, modern plumbing, clean report. The straightforward case. Boil for the stated time, use it for the named uses, and wait for the utility to lift the notice.
A notice in an older neighbourhood with lead service lines. Two hazards at once and they pull in opposite directions. Boil for dish-washing and tooth-brushing if the notice allows; use bottled for anything swallowed.
A notice where nitrate has previously been reported. Do not boil for drinking. MDH is explicit that boiling concentrates nitrate, and the notice was issued for a different problem entirely.
The objections worth answering
“Boiling is the standard advice, so it must be safe.” It is correct for the hazard the notice was issued for. EPA is equally clear that it does not destroy metals or most chemicals, and those are separate hazards that a notice does not consider.
“Surely concentrating is a small effect.” EPA and MDH make the qualitative point and neither quantifies it here, so this page does not either. What is established is the direction: boiling removes water, not the dissolved contaminant.
“My filter is certified, so I am covered.” The notice applies to the supply. Certified claims describe performance under normal conditions, and the utility’s instruction governs.
“Can I shower during a boil notice?” EPA’s list of uses requiring disinfected water names drinking, cooking, prepared drinks, dish-washing and tooth-brushing. It does not name bathing, and nothing sourced here settles it — which is a question for the notice itself.
Who this is for
Households under a boil water notice, and particularly anyone with a lead service line, a nitrate result or a bottle-fed infant, for whom the standard advice needs an exception.
The notice from your utility governs. This page exists because that notice will not mention lead or nitrate.
What to settle first
Does anyone in this house drink water that boiling would make worse?
If no, boil and follow the notice. If yes — lead service line, nitrate result, bottle-fed infant — bottled water for everything swallowed, and boiled water only for the uses that do not end up inside someone.
→ Testing city water, and what your utility already measured → City water treatment, and the three gaps a utility cannot close → Cryptosporidium and Giardia, and why EPA requires removal → Nitrate, which boiling concentrates rather than removes → Distillation, the one device MDH says you can drink through an advisory → Coliform and E. coli: which result triggers a notice → Ground water systems and the machinery upstream of a notice → Why a pressure event triggers a notice: backflow → Main breaks: the event behind many precautionary notices → Which tier your notice is, and the deadline behind it