Has your area ever gotten a boil water alert? If your water utility has issued one, your tap water may not be safe to drink until you boil it or switch to bottled water. Here’s what a boil water advisory actually means, exactly how long you need to boil water to make it safe, and what a whole-house system can do so you don’t have to think about it at all.

What Is a Boil Water Advisory?

A boil water advisory is a notice from your local water utility or health department warning that tap water may be contaminated with bacteria, viruses, or parasites. Utilities issue advisories after events like water main breaks, treatment plant failures, or pressure drops that let untreated groundwater into the distribution system. Sometimes contamination is confirmed. Often, it’s precautionary, issued because conditions made contamination possible, not because testing found it.

Either way, the instructions are the same until the advisory is lifted: treat your tap water as unsafe to drink.

How Long Do You Need to Boil Water?

Bring water to a rolling boil and keep it boiling for a full minute. In the western U.S., many municipalities are above 6,500 feet in elevation, and residents there should boil for three minutes instead, since water boils at a lower temperature the higher you go and needs more time to kill off pathogens. Let it cool before you drink it or use it for anything else.

Boiling kills bacteria, viruses, and parasites. It does not remove chemical contamination, so if your utility’s advisory specifically mentions a chemical issue rather than microbial contamination, boiling alone won’t fix it and you should follow your utility’s specific guidance.

No Way to Boil Water? Use Bottled Water or Disinfect It

If you can’t boil water, bottled water is the simplest fallback. If that’s not available either, you can disinfect tap water with unscented household bleach:

• If the water is clear: add 1/8 teaspoon of unscented bleach per gallon of water, mix, and let it sit for 30 minutes before use.
• If the water is cloudy: strain it through a clean cloth first, then add 1/4 teaspoon of unscented bleach per gallon, mix, and let it sit for 30 minutes.

Never use scented bleach, and don’t use this method for infants or during pregnancy without checking with a doctor first.

What to Avoid During a Boil Water Advisory

• Don’t drink tap water straight from the faucet, even briefly.
• Don’t use tap water to make ice, brush your teeth, or wash produce you’ll eat raw.
• Don’t run your dishwasher unless it has a sanitizing cycle that reaches at least 150°F.
• Don’t wash open wounds with tap water while showering or bathing.
• Throw out any ice, drinks, or food prepared with tap water since the advisory started.

Showering and bathing are generally fine for most healthy adults as long as you avoid swallowing the water. Give young children sponge baths instead, since they’re more likely to swallow bathwater.

Special Precautions for Infants, Pregnant Women, and Anyone Immunocompromised

Boil water advisories carry more risk for some people than others. Infants, pregnant women, older adults, and anyone with a compromised immune system should be extra cautious, since even low levels of contamination can cause more serious illness in these groups. Use only boiled or bottled water for formula, drinking, and food prep, and check with a doctor if you have specific health concerns during an advisory.

Pets are at risk too. Give them boiled or bottled water rather than letting them drink from the tap or an outdoor bowl filled before the advisory.

How Long Does a Boil Water Advisory Last?

There’s no fixed timeline. Advisories typically stay in effect until the water utility collects samples, confirms the water tests clean, and gets clearance from the health department, which can take anywhere from a day to over a week depending on the cause. If you’re told to flush your household plumbing once the advisory lifts, follow that guidance too. Standing water in your pipes during the advisory can still carry contamination even after the utility declares the main supply safe.

Can I Just Use a Filter?

Most water filters, whether they’re attached to your sink nozzle or built into your refrigerator, aren’t designed to filter out bacteria, viruses, or parasites. They’re built to improve taste and clarity, not to handle a contamination event. Relying on a standard at-home filter during a boil water advisory isn’t a safe substitute for boiling or bottled water.

A Drinking Water System That Handles It for You

If you have a filtration system designed specifically to neutralize bacteria and viruses, your water stays safe even during an advisory. Kinetico’s reverse osmosis systems are available with a bacteria and virus cartridge built in, so contamination events that would otherwise send your household straight to bottled water don’t affect you at all.

At Martin Water, we install and service Kinetico whole-house systems across Pennsylvania, Maryland, Delaware, and New York. If a boil water advisory has you rethinking your setup, get a free water analysis and we’ll help you figure out what protection makes sense for your home.