Why a Brita Filter Is Not Enough
During a boil water advisory, your public water supply may be contaminated with disease-causing organisms such as bacteria, viruses, and parasites. Standard activated carbon filters, like those used in Brita pitchers and some refrigerator units, are not designed or certified to eliminate these microscopic pathogens. Instead, they focus on improving the water's taste and odor by trapping chemicals like chlorine.
The activated carbon trap
The primary issue with relying on a Brita filter during a boil water advisory is its filtration mechanism. The activated carbon effectively removes certain chemical contaminants and sediment, but its pores are too large to block tiny microorganisms. A study published by the National Institutes of Health even found that in some cases, filters could become a breeding ground for bacteria if not replaced, leading to higher bacterial counts in filtered water than in tap water. When contaminated water passes through the filter, the pathogens can collect and multiply, potentially making the situation worse.
Contamination risk to the filter itself
Using a Brita filter with contaminated water can also compromise the filter itself. If water containing harmful bacteria or viruses runs through the cartridge, the filter can become a source of contamination. After the advisory is lifted, any contaminated filter that was used must be discarded and replaced to prevent future illness.
Safe Alternatives During a Boil Water Advisory
When a boil water advisory is in effect, you should only use bottled water or properly disinfected tap water for drinking, cooking, brushing your teeth, and washing fruits and vegetables. The CDC and other health officials provide clear guidance on how to make your water safe.
Boiling water
This is the most reliable method for killing disease-causing microorganisms.
To boil water safely:
- If the water is cloudy, first filter it through a clean cloth, coffee filter, or paper towel to remove any sediment.
- Bring the water to a full, rolling boil.
- Maintain the rolling boil for at least one minute (or three minutes at elevations above 6,500 feet).
- Allow the water to cool naturally before use.
- Store the boiled water in a clean, sanitized container with a tight lid.
Using bottled water
Bottled water is a simple and immediate alternative to tap water during an advisory.
Using chemical disinfection
If boiling is not possible, you can disinfect water with unscented household bleach. This method is less reliable for some parasites like Cryptosporidium, but can be effective against bacteria and viruses.
To use bleach for disinfection:
- Use regular, unscented liquid bleach that contains 5–9% sodium hypochlorite and no added cleaners or fragrances.
- Add a specific amount of bleach per gallon of water (for example, 6 drops of 8.25% bleach).
- Stir and let it stand for at least 30 minutes before use.
Specialized emergency filters
Some high-end filtration systems, such as reverse osmosis (RO) or UV purification systems, are capable of removing or inactivating microbiological contaminants. However, these are not standard household pitcher filters and should only be relied upon if they are known to be certified for this purpose and are properly maintained. For more information, you can reference the U.S. Environmental Protection Agency's guidance on emergency disinfection of drinking water.
Comparison of Water Treatment Methods During an Advisory
| Method | Effectiveness Against Pathogens | Removes Chemicals | Cost | Time Required | Ease of Use |
|---|---|---|---|---|---|
| Brita Filter | Ineffective against bacteria, viruses, and parasites. | Effective against chlorine and some metals. | Low initial, plus filter replacements. | Fast filtration. | Very easy. |
| Boiling | Highly Effective against bacteria, viruses, and parasites. | Does not remove chemicals or heavy metals. | Low (energy cost). | 1+ minute boil, plus cooling time. | Easy, requires heat source. |
| Bottled Water | Highly Effective (pre-treated and sealed). | Depends on the bottled water source. | High (per gallon). | Instant access. | Very easy. |
| Chemical Disinfection | Effective against many pathogens, but less so for parasites. | Does not remove chemicals or heavy metals. | Low. | 30+ minute waiting period. | Moderately easy, requires caution. |
| Reverse Osmosis / UV | Highly Effective against pathogens, if properly maintained. | Varies by system; RO systems are very effective. | High (initial purchase and maintenance). | Continuous access, or short treatment time. | Varies by system, more complex. |
Actions to take after the advisory is lifted
Once health officials announce the advisory is over, it is important to take several steps to ensure your water system is completely safe for normal use.
Here's what you need to do:
- Flush the plumbing: Run cold water faucets for several minutes to flush out the pipes. For hot water, run faucets until the water turns cool to clear the tank.
- Discard and replace filters: Throw away any Brita or other water filters that were used during the advisory. Install a new, uncontaminated filter.
- Flush water-using appliances: Run your dishwasher and automatic ice maker through a full cycle. Discard all ice made during and immediately after the advisory period.
- Clean faucet aerators: Remove and clean faucet aerators with a bleach solution to remove any trapped bacteria.
Conclusion
In summary, a Brita filter is not sufficient for a boil water advisory and provides no protection against the microbial contaminants that necessitate such an alert. The safe and recommended practices are to either use bottled water or boil tap water for all consumption, food preparation, and hygiene purposes. For long-term emergency planning, consider storing bottled water or investing in certified purification methods like reverse osmosis or UV treatment. Prioritizing safety by following the guidance from public health officials will protect you and your family from waterborne illness.
