Can You Use a Water Filter During a Boil Advisory?

Hopefully you pay attention to the news and have alerts set up on your emergency radio, because boil advisories are very common.

During a boil alert, the water may be unsafe to drink and must be treated.  Other methods of water treatment can be used during a boil alert, but filtering is not going to be effective.

Here’s why.

 

What Is a Boil Advisory?

boiling water during advisory

Also called a boil alert, a boil advisory is issued whenever there may be contaminants in the tap water.  These contaminants may include:

  • Bacteria
  • Protozoa
  • Viruses

Boiling water for at least 1 minute will kill all of these contaminants.

To properly boil water during an alert, you should heat the water until you see bubbles coming to the surface.  This is known as a “rolling boil.”  Start counting your 1 minute from when the water is at a rolling boil.

Note: If you live at an elevation of above 6,561 feet, then you’ll need to boil the water for at least 3 minutes.  This is because water boils at a lower temperature at high altitudes.

Why Are Boil Advisories Issued?

There are four main reasons that boil alerts are issued.  Depending on the reason for the boil alert, different contaminants might be present.

  • Water Main Breaks: When a water main breaks, contaminants from the soil around the pipe can enter the pipes.
  • Power Outages: During large-scale power outages, the water treatment plant may stop working. If your power goes out, don’t use any tap water until you’ve checked whether there is a boil alert in place!
  • Sewage Leaks: When sewage pipes leak and get into the water distribution system, there is a huge risk of viral, bacterial, and other pathogenic contaminants.
  • Pressure Loss: The loss of pressure in the water system can allow contaminants to enter the pipes.
  • Natural Disasters: Especially during flooding, the water treatment center is unable to handle all of the water. Untreated water gets into the distribution system.  Because sewage mains overflow or break during disasters (such as earthquakes), the water could be full of contaminants.

 

Why Water Filters Aren’t Adequate During Boil Advisories

A good water filter (I’m not talking about your standard kitchen filter) will have a micron rating of 0.2 or less.  These water filters are very effective at removing bacteria and protozoa.

Water filters will NOT remove viruses though!

During some boil alerts, such as those caused by water main breaks, there is little risk of viral contamination.  In theory, a good water filter could make the water safe to drink.  However, the water department rarely tells us why the boil alert was issued.   Always assume the worst and treat the water for viruses too.

Depending on where you live, there might actually be a big risk of viruses in your water.  One EPA study looked at drinking water from 14 communities which don’t treat the water with chlorine or UV light.   They found that 24% of water samples contained viruses!

Boil Alerts and Chemical Spills

One time you won’t hear a boil alert is after a chemical spill or other type of chemical contamination. Boiling will not remove chemicals from water.  In fact, boiling actually makes the threat worse because evaporation concentrates the chemicals.

If a chemical spill occurs, your city will tell residents to only drink bottled water. These alerts are usually called “Do Not Drink” or “Do Not Use” alerts. This actually happens quite frequently, such as the 2016 chemical spill in Corpus Christi and the 2017 chemical runoff in Airway Heights.

The takeaway point? Always have bottled water in addition to a way to boil water!

Recommended: The Ultimate Guide To Emergency Water

 

Water Safety during a Boil Advisory

Use Only Boiled Water for:

  • Drinking and cooking
  • Infant formula
  • Pets’ water
  • Brushing teeth
  • Washing produce
  • Making coffee (most coffee makers don’t get hot enough to purify the water)

Showering during a Boil Advisory: 

You can safely shower with tap water during a boil advisory.  However, young children should be carefully supervised to make sure they don’t swallow any water.  To reduce risk, give them sponge baths until the boil alert is lifted.

Washing Dishes during a Boil Advisory:

If your dishwasher has a “hot-Sani” setting, then it can be used for washing dishes during the boil alert.  Otherwise, you will need to sanitize your dishes after washing them with tap water.

To sanitize your dishes,

  • Mix 1oz (6 teaspoons) of unscented bleach with 3 gallons of lukewarm water.
  • Soak dishes in this solution for 1 minute.
  • Let air dry.

What If the Tap Water is Yellow or Cloudy?

So long as you’ve boiled the water, even yellow or cloud water will be safe to drink.

Note that the water can still have a nasty taste to it.  To get rid of the bad taste, add a pinch of salt and let it sit before drinking.   Or, add lemon juice or powdered drinks to mask the bad taste.

 

Alternatives to Boiling Water

If you are unable to boil water for treating it, there are some other options.

1. Bleach

Unscented bleach is very effective and perfectly safe for treating water.  It will kill bacteria, parasites, and viruses.   You can find detailed instructions on how to treat water with bleach here.

how to purify water with bleach

2. Water Purification Tablets or Drops

These are great to add to your disaster supplies.  They are small, last a long time, and very easy to use.   You can get them here.

3. UV Water Treatment

UV water treatment systems look like pens that you stick into the water.  They shoot out UV rays which scramble the DNA of bacteria, protozoa, and viruses.

They are highly effective, though there is some debate about how long the effect lasts for.  If you wait too long to consume the water, the DNA could “unscramble” and cause the pathogens to become activate again.

I’m not the biggest fan of UV water treatment systems for disaster prep because they rely on batteries to work and they are expensive.  You can have a look at one here on Amazon if you are interested.

4. Sawyer Point Zero Two Water Filter

As a general rule, no water filter will make water safe during a boil advisory.  Even the best camping water filters won’t remove viruses.  However, there is one exception.

The “Point Zero Two” water filter made by Sawyer filters down to 0.02 microns (hence the name).  This is small enough to filter out even viruses.

The water filter is fairly pricey but it comes with a faucet adapter and lasts a lifetime.


 

Key Disaster Preparedness Takeaways:

  • Have an emergency stove for boiling water (read about options here).
  • Keep unscented bleach in with your disaster supplies.
  • Stockpile bottled water (read how here).
  • Get an emergency radio so you can stay informed about boil alerts.

I’m Jacob Hunter, founder of Primal Survivor.
I believe in empowering people with the knowledge to prepare and survive in the modern world.

More about Jacob here.

Leave a comment

  1. Not true, “Purifiers” WILL purify contaminated water. Both virus, bacteria, and chemical contamination can be done.
    Whatever purifier you choose, you need to pre-filter to at least “clear water” (sediment, debris, etc) filter to prolong the use of your purifier.
    Start wit gathering water from clear, odor free as possible sources. Then it is recommended (CDC) if the water is of unknown quality that you add 8-10 drops plain bleach. Let stand at least one hour before running through your purifier.
    I use Berkey black filters in my stainless filter system. They are rated for 3000 gallons, depending on the level of contaminants. Pre-filtering with say… bio-sand units will clean the water up quite well.
    One other thing. Bleach can drop in effectiveness given time and evaporation. Storing liquid bleach in large quantities is not recommended. Given that the dry form of bleach used in pools is contaminated with other chemicals, as far as I’ve found, makes this too not recommended. There is hope though. MSR (Mountain Safety Research) has a devision devoted to water purification. They have developed a small, powerful (provides enough bleach generation) enough to provide sanitation for entire villages. The power source is 12 volts and can be supplied from a moped battery, common in many villages.
    Hope this helps…

    • Purifier is a pretty generic term which can be used with many different methods of removing contaminants from water. As far as filters go, most of these (aside from some newer, specialized filters like the Sawyer Point Zero Two mentioned) will not remove viruses. Activated carbon filters may get out chemicals, but they aren’t as effective on bacteria.

      The bottom line? No water purification method is perfect for all scenarios. You may need to combine purification methods to ensure water is safe to drink.

Leave a Comment