Boil Water Advisory: What It Actually Means and What to Do

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A boil water advisory means your utility has found, or suspects, contamination in the water supply — often tied to a water main break, a treatment plant issue, or a loss of pressure that can happen during a power outage. The rules are specific and easy to get wrong under stress, so here’s exactly what the advisory means and what to actually do while it’s in effect.

Why Advisories Happen During Power Outages

Water treatment and pumping systems depend on electricity. When a plant loses power or a pressure drop occurs anywhere in the distribution system, there’s a real risk that contaminants can enter the water through cracks, joints, or backflow while pressure is low — which is exactly why boil water advisories are common companions to extended outages, even if your own tap water looks and smells completely normal. Our emergency water purification guide covers additional methods beyond boiling if you need options. The advisory is precautionary as much as it is reactive; utilities issue it because the risk exists, not necessarily because contamination has been confirmed.

How to Actually Boil Water Correctly

Bring water to a full rolling boil — not a simmer, not scattered small bubbles, but large, continuously breaking bubbles across the surface — and hold it there for at least one full minute. Let it cool before drinking or using it. This single-minute rolling boil is the standard most public health guidance points to for eliminating the pathogens of concern in a typical municipal water contamination event. Boiling for less time, or only heating water to a light simmer, doesn’t reliably meet that standard.

What You Should Not Do With Tap Water During an Advisory

Don’t drink it, even briefly or “just to rinse your mouth.” Don’t brush your teeth with it. Don’t wash fruits or vegetables you plan to eat raw. Don’t wash dishes with it unless you’re using the bleach method below. Don’t use it to make ice. Don’t give it to pets as drinking water. Don’t use it to prepare infant formula. These restrictions exist because the same contamination risk that applies to drinking water applies to anything that enters your body or an infant’s system, even indirectly.

What’s Actually Safe to Do

Showering and bathing are generally fine for most healthy adults, though it’s worth being cautious about swallowing water and using extra care with young children, elderly household members, and anyone with a compromised immune system or open wounds. Shaving with tap water is fine. Laundry is fine — the advisory doesn’t extend to washing clothes. Watering outdoor plants and lawns is fine. The advisory is specifically about anything that could be ingested or that contacts food, not about general household water use.

Washing Dishes Without Boiling Every Batch

If you don’t want to boil water for every round of dishes, there’s a bleach-based alternative: wash and rinse dishes as normal, then prepare a sanitizing solution of about 1 teaspoon of unscented household bleach per gallon of warm water, and soak the rinsed dishes in that solution for at least one minute before air drying. Use only plain, unscented bleach — scented bleach or bleach with added cleaning agents can leave residue you don’t want on dishware. A dishwasher with a “sanitize” cycle and hot-water wash is also typically considered safe during an advisory, since it reaches the temperatures needed to address the same risk.

What to Do With Ice You Already Made

Discard any ice made during the advisory period, and don’t use your ice maker until the advisory is lifted and you’ve flushed your water lines. If you’re relying on a freezer during a power outage anyway, this is a good moment to just keep that ice separate from anything you’d consume, and start over once both the outage and the advisory have resolved.

What to Do When the Advisory Is Lifted

Don’t assume your tap water is immediately back to normal the moment the utility announces the advisory is over. Flush your home’s plumbing system by running all cold-water taps for about 15 minutes, working from the lowest floor of the home to the highest, to clear out any water that sat in the pipes during the advisory. Discard any ice made during the advisory, plus run through and discard the next two to three batches your ice maker produces after that, since residual water can linger in the line. Run your water filter’s flush cycle if you have a built-in filtration system, and consider replacing filter cartridges if the advisory involved confirmed contamination rather than a precautionary pressure-loss issue.

Stocking Water Ahead of a Known Risk

If your area is prone to advisories during storms or outages, filling clean containers or a bathtub with tap water before an anticipated outage gives you a supply for flushing toilets and other non-drinking uses without drawing down bottled water you’re saving to actually drink — our water storage and purification guide covers how much to actually keep on hand, and our water-per-person guide breaks that down by household size. This is a five-minute step worth doing any time a storm forecast or planned utility maintenance gives you advance warning.

Key takeaways

• Boil water advisories are common during power outages because treatment and pumping systems depend on electricity, and pressure loss can let contaminants in.
• Boiling means a full rolling boil held for at least one minute — not a simmer, and not a shorter boil time.
• Don’t drink, brush teeth with, wash produce with, or make ice with tap water during an advisory; showering, laundry, and watering plants are generally fine.
• A bleach solution (1 tsp unscented bleach per gallon of warm water, 1-minute soak) can sanitize rinsed dishes as an alternative to boiling water for every load.
• When the advisory lifts, flush your plumbing by running all cold taps for about 15 minutes, and discard ice made during the advisory plus the next few batches after.

FAQ

Can I use a water filter pitcher instead of boiling during an advisory? Most standard consumer pitcher filters aren’t certified to remove the biological contaminants a boil water advisory is concerned with, so don’t rely on one as a substitute for boiling unless it’s specifically certified for that purpose. Our emergency water filter guide covers which models are actually rated for this. Check the filter’s certification before trusting it during an advisory.

Is bottled water automatically safe during a boil water advisory? Yes, commercially bottled water is unaffected by a municipal boil water advisory since it isn’t drawn from the same distribution system — it’s a reliable option if you’d rather not boil water for every use during the advisory period.

How long do boil water advisories typically last? It varies widely depending on the cause — a pressure-loss advisory tied to a short outage might lift within a day once testing confirms the water is safe, while contamination tied to a treatment plant issue can take several days. Your utility will announce when it’s lifted; don’t assume it’s over just because your power or water pressure has returned to normal.