When something goes wrong with the water, the instinct is to boil it. That reflex has been passed down for generations, and it earned its place: boiling works against the threats that historically made water dangerous.
Those threats were bacteria, viruses, and parasites. They're not what most Connecticut households are up against today. The problems here now are chemical: lead, PFAS, nitrates, arsenic, disinfection byproducts. Boiling does not help with any of them. For some, it actively makes things worse.
What Boiling Actually Does
Boiling water to a rolling boil for one minute kills:
- Bacteria, including E. coli, Salmonella, and Campylobacter
- Viruses, including norovirus and hepatitis A
- Parasites, including Giardia and Cryptosporidium
That matters. When a Connecticut town issues a boil water notice, usually after a main break, a treatment failure, or flooding that may have let biological contamination in, boiling is exactly the right response to that specific risk. The CDC recommends a rolling boil for one minute as the standard protocol.
What Doesn't Boiling Remove from Water?
Boiling does not remove:
- Lead: Lead is a dissolved metal. It doesn't evaporate when water boils, so it stays put. Worse, as water leaves as steam, what's left gets more concentrated. The same amount of lead in less water means a higher lead concentration.
- PFAS: PFAS compounds don't evaporate at boiling temperatures. They stay in the water, and as the volume drops, their concentration rises.
- Nitrates: Nitrates are dissolved salts. They don't evaporate. Boiling concentrates them.
- Arsenic: Same story as lead. A dissolved metal that gets more concentrated as water boils away.
- Chlorine byproducts: Trihalomethanes (THMs) do partially evaporate during boiling. Haloacetic acids (HAAs) do not, and may concentrate.
A Yale School of the Environment study published in February 2026 said it plainly. Boiling is the recommended response to biological contamination, but "boiling does not remove metals, and can sometimes concentrate them."
The Connecticut Context
Connecticut's most common water quality concerns are chemical, not biological. Lead in service lines and old solder. PFAS in groundwater-dependent supplies. Nitrates in agricultural well water. Arsenic in granite bedrock geology.
For every one of these, boiling isn't merely useless. It can backfire. A homeowner worried about lead who responds by boiling the water is concentrating the exact thing they're trying to avoid.
Chemical contamination calls for filtration. For lead, an NSF/ANSI 53 certified filter. For PFAS, an NSF/ANSI 58 certified reverse osmosis system or an NSF P473 certified filter. For nitrates, reverse osmosis. For arsenic, reverse osmosis or activated alumina. If you want a closer look at what reverse osmosis actually removes, see our complete breakdown of RO filtration.
Boil water notices exist for biological contamination. They aren't a general-purpose water quality fix. So if you're boiling because you're uneasy about your water, and you haven't identified which contaminant you're worried about, the first step is to test. Your annual water quality report is a decent starting point, and here's how to actually read it.
Want ZIP-level context before deciding whether to test? Enter your ZIP code at CheckYourTap.com to see available public-system or regional monitoring records associated with the ZIP. This is not a test of a tap, well, or property. Free, in 30 seconds.
Keep Reading
- Reverse Osmosis Removes Almost Everything. Here's What Connecticut Homeowners Need to Know Before Buying One.
- Your Water Quality Report Arrived. Here's How to Actually Read It.
- A Practical Guide to Water Quality in Connecticut's Major Towns: What's Actually in the Water Where You Live
Sources: Yale School of the Environment / Water journal, February 2026; EPA Boil Water Notice Guidance; CDC Safe Water Guidance; NSF International Filter Certification Standards; EPA Drinking Water Contaminant List.
